Trimble Outdoors GPS Receiver SPSX51 User Manual

user guide  
®
Trimble SPSx51  
Modular GPS Receivers  
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USER GUIDE  
®
Trimble SPSx51 Modular GPS Receivers  
Version 3.60  
Revision A  
January 2008  
F
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Corporate Office  
Europe  
Trimble Navigation Limited  
935 Stewart Drive  
This product (the SPSx51 Modular GPS receiver) is  
intended to be used in all EU member countries, Norway,  
and Switzerland.  
This product has been tested and found to comply with the  
requirements for a Class B device pursuant to European Council  
Directive 89/336/EEC on EMC, thereby satisfying the requirements  
for CE Marking and sale within the European Economic Area (EEA).  
Contains Bluetooth radio module PBA 31308. These requirements  
are designed to provide reasonable protection against harmful  
interference when the equipment is operated in a residential or  
commercial environment. The 450 MHZ (PMR) bands and 2.4 GHz  
are non-harmonized throughout Europe.  
www.trimble.com  
Construction Business Area  
Trimble Navigation Limited  
Construction Business Area  
5475 Kellenburger Road  
Dayton, Ohio 45424-1099  
USA  
800-538-7800 (toll free in USA)  
+1-937-245-5600 Phone  
+1-937-233-9004 Fax  
Australia and New Zealand  
This product conforms with the regulatory requirements of  
the Australian Communications Authority (ACA) EMC  
framework, thus satisfying the requirements for C-Tick  
Marking and sale within Australia and New Zealand.  
Legal Notices  
© 2006–2007, Trimble Navigation Limited. All rights reserved.  
Trimble, and the Globe & Triangle logo are trademarks of Trimble  
Navigation Limited, registered in the United States Patent and  
Trademark Office and in other countries. AutoBase, CMR, CMR+,  
HYDROpro, Maxwell, Micro-Centered, TGO, SiteNet, TRIMMARK,  
TRIMTALK, TSC2, TSCe, VRS, Zephyr, and Zephyr Geodetic are  
trademarks of Trimble Navigation Limited.  
The Bluetooth word mark and logos are owned by the Bluetooth  
SIG, Inc. and any use of such marks by Trimble Navigation Limited  
is under license.  
Taiwan – Battery Recycling Requirements  
The product contains a removable Lithium-ion battery.  
Taiwanese regulations require that waste batteries are  
recycled.  
廢電池請回收  
Notice to Our European Union Customers  
Directive 1999/5/EC  
Hereby, Trimble Navigation, declares that the SPSx50 and SPSx51  
GPS receivers are in compliance with the essential requirements  
and other relevant provisions of Directive 1999/5/EC.  
Microsoft, Windows, and Windows NT are either registered  
trademarks or trademarks of Microsoft Corporation in the United  
States and/or other countries.  
Restriction of Use of Certain Hazardous Substances  
in Electrical and Electronic Equipment (RoHS)  
The following statement only applies to the SPSx51 Modular GPS  
receiver (no internal radio model and 450 MHz internal radio  
models only)  
This Trimble product complies in all material respects with  
DIRECTIVE 2002/95/EC OF THE EUROPEAN PARLIAMENT AND  
OF THE COUNCIL of 27 January 2003 on the restriction of the use of  
certain hazardous substances in electrical and electronic  
equipment (RoHS Directive) and Amendment 2005/618/EC filed  
under C(2005) 3143, with exemptions for lead in solder pursuant to  
Paragraph 7 of the Annex to the RoHS Directive applied.  
All other trademarks are the property of their respective owners.  
Release Notice  
This is the January 2008 release (Revision A) of the SPSx51 Modular  
GPS Receivers User Guide. It applies to version 3.60 of the receiver  
firmware.  
Product Limited Warranty Information  
For applicable product Limited Warranty information, please refer  
to the Limited Warranty Card included with this Trimble product,  
or consult your local Trimble authorized dealer.  
Notices  
Class B Statement – Notice to Users. This equipment has been  
tested and found to comply with the limits for a Class B digital  
device, pursuant to Part 15 of the FCC rules and Part 90. These  
limits are designed to provide reasonable protection against  
harmful interference in a residential installation. This equipment  
generates, uses, and can radiate radio frequency energy and, if not  
installed and used in accordance with the instructions, may cause  
harmful interference to radio communication. However, there is no  
guarantee that interference will not occur in a particular  
installation. If this equipment does cause harmful interference to  
radio or television reception, which can be determined by turning  
the equipment off and on, the user is encouraged to try to correct  
the interference by one or more of the following measures:  
– Reorient or relocate the receiving antenna.  
Waste Electrical and Electronic Equipment (WEEE)  
to www.trimble.com/ev.shtml.  
Recycling in Europe: To recycle Trimble WEEE (Waste  
Electrical and Electronic Equipment, products that run on  
electrical power.), Call +31 497 53 24 30, and ask for the  
"WEEE Associate". Or, mail a request for recycling  
instructions to:  
Trimble Europe BV  
c/o Menlo Worldwide Logistics  
Meerheide 45  
5521 DZ Eersel, NL  
– Increase the separation between the equipment and the receiver.  
– Connect the equipment into an outlet on a circuit different from  
that to which the receiver is connected.  
Declaration of Conformity  
We, Trimble Navigation Limited,  
– Consult the dealer or an experienced radio/TV technician for  
help.  
935 Stewart Drive  
PO Box 3642  
Changes and modifications not expressly approved by the  
manufacturer or registrant of this equipment can void your  
authority to operate this equipment under Federal  
Sunnyvale, CA 94088-3642  
United States  
Communications Commission rules.  
+1-408-481-8000  
Canada  
This Class B digital apparatus complies with Canadian ICES-003.  
Cet appareil numérique de la classe B est conforme à la norme  
NMB-003 du Canada.  
declare under sole responsibility that the products:  
SPSx51 Modular GPS receiver  
comply with Part 15 of FCC Rules.  
This apparatus complies with Canadian RSS-GEN, RSS-310,  
RSS-210, and RSS-119.  
Cet appareil est conforme à la norme CNR-GEN, CNR-310,  
CNR-210, et CNR-119 du Canada.  
Operation is subject to the following two conditions:  
(1) this device may not cause harmful interference, and  
(2) this device must accept any interference received, including  
interference that may cause undesired operation.  
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Safety Information  
Before you use your Trimble® SPS GPS receiver, make sure that you have read and  
understood all safety requirements.  
Regulations and safety  
The receivers contain an internal radio-modem and can send signals through  
Bluetooth® wireless technology or through an external data communications radio.  
Regulations regarding the use of the 450 MHz radio-modems vary greatly from country  
to country. In some countries, the unit can be used without obtaining an end-user  
license. Other countries require end-user licensing. For licensing information, consult  
your local Trimble dealer. Bluetooth and 900 MHz radio-modems operate in  
license-free bands.  
Before operating an SPSx51 Modular GPS receiver, determine if authorization or a  
license to operate the unit is required in your country. It is the responsibility of the end  
user to obtain an operator’s permit or license for the receiver for the location or  
country of use.  
For FCC regulations, see Notices, page 2.  
Type approval  
Type approval, or acceptance, covers technical parameters of the equipment related to  
emissions that can cause interference. Type approval is granted to the manufacturer of  
the transmission equipment, independent from the operation or licensing of the units.  
Some countries have unique technical requirements for operation in particular  
radio-modem frequency bands. To comply with those requirements, Trimble may have  
modified your equipment to be granted Type approval. Unauthorized modification of  
the units voids the Type approval, the warranty, and the operational license of the  
equipment.  
Exposure to radio frequency radiation  
For 450 MHz radio  
Safety. Exposure to RF energy is an important safety consideration. The FCC has  
adopted a safety standard for human exposure to radio frequency electromagnetic  
energy emitted by FCC regulated equipment as a result of its actions in General Docket  
79-144 on March 13, 1986.  
Proper use of this radio modem results in exposure below government limits. The  
following precautions are recommended:  
DO NOT operate the transmitter when someone is within 20 cm (7.8 inches) of  
the antenna.  
DO NOT operate the transmitter unless all RF connectors are secure and any  
open connectors are properly terminated.  
DO NOT operate the equipment near electrical blasting caps or in an explosive  
atmosphere.  
SPSx51 Modular GPS Receivers User Guide  
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Safety Information  
All equipment must be properly grounded according to Trimble installation  
instructions for safe operation.  
All equipment should be serviced only by a qualified technician.  
1
For license-free 900 MHz radio  
CAUTION – For your own safety, and in terms of the RF exposure requirements of the  
FCC, always observe the precautions listed here.  
C
DO NOT operate the transmitter when someone is within 20 cm (7.8 inches) of  
the antenna.  
Do not co-locate the antenna with any other transmitting device.  
For Bluetooth radio  
The radiated output power of the internal Bluetooth wireless radio is far below the  
FCC radio frequency exposure limits. Nevertheless, the wireless radio shall be used in  
such a manner that the Trimble receiver is 20 cm or further from the human body. The  
internal wireless radio operates within guidelines found in radio frequency safety  
standards and recommendations, which reflect the consensus of the scientific  
community. Trimble therefore believes that the internal wireless radio is safe for use by  
consumers. The level of energy emitted is far less than the electromagnetic energy  
emitted by wireless devices such as mobile phones. However, the use of wireless radios  
may be restricted in some situations or environments, such as on aircraft. If you are  
unsure of restrictions, you are encouraged to ask for authorization before turning on  
the wireless radio.  
Installing antennas  
CAUTION – For your own safety, and in terms of the RF exposure requirements of the  
FCC, always observe these precautions:  
– Always maintain a minimum separation distance of 20 cm (7.8 inches) between yourself  
and the radiating antenna.  
– Do not co-locate the antenna with any other transmitting device.  
C
This device has been designed to operate with the antennas listed below. Antennas not  
included in this list are strictly prohibited for use with this device. The required  
antenna impedance is 50 ohms.  
The antennas that can be used (country dependent) with the 450 MHz radio are 0 dBi  
and 5 dBi whip antennas. The antennas that can be used (country dependent) with the  
900 MHz radio are 0 dBi, 3 dBi, and 5 dBi whip antennas.  
To reduce potential radio interference to other users, the antenna type and its gain  
should be so chosen so that the equivalent isotropically radiated power (e.i.r.p.) is not  
more than that permitted for successful communication.  
1.  
900 MHz radios are not used in Europe.  
4
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Safety Information  
Battery safety  
WARNING – Do not damage the rechargeable Lithium-ion battery. A damaged battery  
can cause an explosion or fire, and can result in personal injury and/or property damage.  
To prevent injury or damage:  
C
– Do not use or charge the battery if it appears to be damaged. Signs of damage include,  
but are not limited to, discoloration, warping, and leaking battery fluid.  
– Do not expose the battery to fire, high temperature, or direct sunlight.  
– Do not immerse the battery in water.  
– Do not use or store the battery inside a vehicle during hot weather.  
– Do not drop or puncture the battery.  
– Do not open the battery or short-circuit its contacts.  
WARNING – Avoid contact with the rechargeable Lithium-ion battery if it appears to be  
leaking. Battery fluid is corrosive, and contact with it can result in personal injury and/or  
property damage.  
C
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To prevent injury or damage:  
– If the battery leaks, avoid contact with the battery fluid.  
– If battery fluid gets into your eyes, immediately rinse your eyes with clean water and  
seek medical attention. Do not rub your eyes!  
– If battery fluid gets onto your skin or clothing, immediately use clean water to wash off  
the battery fluid.  
WARNING – Charge and use the rechargeable Lithium-ion battery only in strict  
accordance with the instructions. Charging or using the battery in unauthorized  
equipment can cause an explosion or fire, and can result in personal injury and/or  
equipment damage.  
To prevent injury or damage:  
– Do not charge or use the battery if it appears to be damaged or leaking.  
– Charge the Lithium-ion battery only in a Trimble product that is specified to charge it.  
Be sure to follow all instructions that are provided with the battery charger.  
– Discontinue charging a battery that gives off extreme heat or a burning odor.  
– Use the battery only in Trimble equipment that is specified to use it.  
– Use the battery only for its intended use and according to the instructions in the product  
documentation.  
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Safety Information  
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Contents  
SPS751 standard features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19  
Use and care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23  
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Contents  
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Contents  
SPSx51 Modular GPS Receivers User Guide  
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Contents  
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Contents  
SPSx51 Modular GPS Receivers User Guide 11  
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Contents  
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C H A P T E R  
1
correction services. The SPS551 is ideal for  
mobile applications on marine vessels and site  
vehicles where Real-Time Kinematic (RTK)  
accuracy is not needed. The SPS551 can be used  
with the SPS551H GPS receiver to provide both  
position and precise heading solutions for  
marine applications. The SPS551 can be  
upgraded to use GLONASS signals and to use  
GPS L2C signals.  
Introduction  
Welcome to the SPSx51 Modular GPS Receivers  
User Guide. This manual describes how to set up  
and use the Trimble® SPSx51 Modular GPS  
receivers.  
1
About the SPSx51 receivers  
The SPSx51 Modular GPS receiver family  
comprises the following receivers:  
SPS551H GPS receiver  
The Trimble SPS551H is an add-on receiver that  
can be combined with the SPS551, SPS751 Max,  
or SPS851 Extreme to provide a precise heading  
capability using Trimble moving base technology.  
SPS551  
SPS551H  
SPS651  
The SPS551H is also available with GLONASS to  
provide a robust heading solution in a hostile  
environment.  
SPS751 Basic base  
SPS751 Basic rover  
SPS751 Max  
SPS851  
SPS651 Location GPS receiver with  
precise vertical accuracy  
The SPS651 is a Location GPS receiver with  
precise vertical and decimeter horizontal  
positioning. The receiver is part of the  
vehicle-mounted Trimble Site Supervisor System  
and used with the SCS900 Site Controller  
Software Tablet Edition it is designed to provide  
site supervisors with cost-effective real-time  
positioning information.  
SPS551 GPS receiver  
The Trimble SPS551 is a dual-frequency Location  
GPS receiver, which provides up to decimeter  
accuracy depending on the augmentation used.  
The SPS551 provides decimeter precision when  
used in Location RTK mode with RTK  
corrections through the internal radio or  
The SPS651 can operate in all Location GPS  
modes including SBAS, DGPS, OmniSTAR  
(VBS/HP/XP services), and Location RTK mode.  
It can be upgraded to use GLONASS signals and  
to use GPS L2C signals.  
Internet. The SPS551 can operate as a DGPS  
reference station or as a DGPS rover receiver, and  
can use Satellite Based Augmentation Systems  
(SBAS). The receiver can also function as a rover  
receiver that uses OmniSTAR XP, HP, or VBS  
SPSx51 Modular GPS Receivers User Guide 13  
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1
Introduction  
Trimble training courses – Consider a  
training course to help you use your GPS  
system to its fullest potential. For more  
information, go to the Trimble website at  
www.trimble.com/training.html.  
SPS751 GPS receiver  
The Trimble SPS751 is a dual-frequency GPS  
receiver with the ability to receive OmniSTAR  
corrections. The receiver is available in the  
following configurations:  
SPS751 Basic base  
SPS751 Basic rover  
SPS751 Max  
Technical support  
If you have a problem and cannot find the  
information you need in the product  
documentation, contact your local dealer.  
Alternatively, go to the Support area of the  
Trimble website  
(www.trimble.com/support.shtml). Select the  
product you need information on. Product  
updates, documentation, and any support issues  
are available for download.  
The SPS751 can be configured using the keypad  
and display, a web browser, or the Trimble  
SCS900 Site Controller software. The SPS751  
makes it easy to set up a mobile base station or a  
permanent base station for continuous  
operation. The SPS751 is also an ideal mobile  
receiver for semi-permanent mounting on  
vehicles and marine vessels.  
If you need to contact Trimble technical support,  
complete the online inquiry form at  
www.trimble.com/support_form.asp.  
SPS851 GPS receiver  
The Trimble SPS851 is a triple-frequency GPS  
plus GLONASS receiver with the ability to receive  
OmniSTAR corrections. The SPS851 can operate  
as a base station or rover. The receiver can be  
configured using the keypad and display, web  
browser, or Trimble SCS900 Site Controller  
software. The SPS851 makes it easy to set up a  
mobile base station or a permanent base station  
for continuous operation. The SPS851 is also an  
ideal mobile receiver for semi-permanent  
Your comments  
Your feedback about the supporting  
revision. Email your comments to  
1
mounting on vehicles and marine vessels.  
Related information  
Sources of related information include the  
following:  
Release notes – The release notes describe  
new features of the product, information not  
included in the manuals, and any changes to  
the manuals. They are provided as a .pdf file  
on the Trimble SPS GPS Receiver CD or you  
can download them from the Trimble  
website (www.trimble.com/support.shtml).  
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C H A P T E R  
2
Features and Functions  
2
In this chapter:  
Trimble SPSx51 Modular GPS receivers are ideal  
for the following infrastructure development, site  
development, and marine construction  
applications:  
Mobile base station for RTK or DGPS  
applications  
Permanent base station RTK or DGPS  
applications (not available in the SPS551H)  
RTK rover on rod, backpack, site vehicle, or  
marine vessel  
Site and marine location applications using  
Location GPS augmentation including  
OmniSTAR, Location RTK, SBAS, and DGPS  
RTCM  
You can use the receivers with the Trimble  
SCS900 Site Controller software.  
These receivers all feature a keypad and display  
so you can configure the receiver without using a  
controller or computer.  
All the receivers can record GPS data to the  
internal memory, and transfer the data over a  
serial or Ethernet connection.  
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2
Features and Functions  
SPS551 features  
The receiver provides the following features:  
Integrated GPS receiver and radio  
Location RTK capable – Location RTK precision of 10 cm horizontal and 10 cm  
vertical  
Not upgradable to full RTK (SPS751 or SPS851)  
Optional 450 or 900 MHz internal radio  
72-channel L1 C/A Code, L1/L2 Full Cycle Carrier. Upgradable to L2C and  
GLONASS L1/L2 Full Cycle Carrier  
OmniSTAR XP/HP/VBS service capable  
4-channel WAAS (Wide Area Augmentation System), EGNOS (European  
Geo-Stationary Navigation System), and MSAS Satellite Based Augmentation  
(SBAS) compatible  
Long-life integrated battery, typically provides 12 hours as a rover with internal  
radio  
Configuration and monitoring interface through the following methods:  
Web interface  
Networked or peer-to-peer Ethernet  
Integrated display and keyboard  
Trimble SCS900 Site Controller Software Tablet Edition  
Integrated Bluetooth wireless technology for cable-free configuration and  
operation with a laptop or controller  
Attached or external radio antenna for rover operation  
Small, lightweight design – 1.65 kg (3.64 lbs) receiver only, including the battery;  
4 kg (8.82 lbs) complete system weight (rover including controller and rod)  
Vehicle and marine vessel mounting options for Supervisor and Dredging  
applications  
Easy-to-use menu system for rapid configuration and status checking  
Rugged, weatherproof construction with an IP67 environmental rating  
–40 ×C to +65 ×C (–40 ×F to +149 ×F) operating temperature range  
9.5 V to 28 V DC input power range, with over-voltage protection  
Capable of rover operation within a VRS (Virtual Reference Station) network  
Moving baseline and heading capability when combined with an appropriate  
SPSx51, SPSx50, or SPS551H receiver  
RoHS compliant  
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Features and Functions  
2
Can be upgraded to receive GLONASS signals.  
Note – When the receiver is upgraded to GLONASS, the GA510 rover GPS antenna should  
be replaced with the ZephyrModel 2 antenna.  
1 Pulse-per-second (1PPS) output  
SPS551 Receiver optional features  
Internal 450 MHz (3 frequency bands) radio with transmit and receive capability  
Internal 900 MHz radio with transmit and receive capability  
SPS551H features  
The SPS551H receiver is an add-on receiver, which provides Precise GPS heading  
capability when combined with another SPSx51 Modular GPS receiver (excluding the  
SPS751 Basic base and or another SPS551H receiver). The SPS551H cannot be used  
alone.  
The SPS551H receiver provides the following features:  
Low-cost Precise GPS Heading add-on GPS receiver for the Trimble SPS551,  
SPS751, or SPS851 receivers  
Connection to another GPS receiver through Bluetooth wireless technology or a  
serial port  
10 Hz heading update rate in NMEA 0183 and Trimble binary formats  
Configuration and heading on a two-line display  
Includes a GA510 rover or Zephyr Model 2 rover GPS antenna, mounting  
bracket, and short interconnecting cable  
RoHS compliant  
Tracks up to 24 GPS satellites  
Can be upgraded to receive GLONASS signals  
1 Pulse-per-second (1PPS) output  
The receiver is ideal for projects that require the precise heading of a vessel or  
structure.  
SPS651 features  
The receiver provides the following features:  
Integrated GPS receiver and radio  
Precise Vertical measurement when in Location RTK mode – Location RTK  
precision of 10 cm horizontal and 2 cm vertical  
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2
Features and Functions  
Not upgradable to full RTK (SPS751 or SPS851)  
Optional 450 or 900 MHz internal radio  
72-channel L1 C/A Code, L1/L2 Full Cycle Carrier. Upgradable to L2C and  
GLONASS L1/L2 Full Cycle Carrier  
OmniSTAR XP/HP/VBS service capable  
4-channel WAAS (Wide Area Augmentation System), EGNOS (European  
Geo-Stationary Navigation System), and MSAS Satellite Based Augmentation  
(SBAS) compatible  
Long-life integrated battery, typically provides 12 hours as a rover with internal  
radio  
Configuration and monitoring interface through the following methods:  
Web interface  
Networked or peer-to-peer Ethernet  
Integrated display and keyboard  
Trimble SCS900 Site Controller Software Tablet Edition  
Integrated Bluetooth wireless technology for cable-free configuration and  
operation with a laptop or controller  
Attached or external radio antenna for rover operation  
Small, lightweight design – 1.65 kg (3.64 lbs) receiver only, including the battery;  
4 kg (8.82 lbs) complete system weight (rover including controller and rod)  
Vehicle and marine vessel mounting options for Supervisor and Dredging  
applications  
Easy-to-use menu system for rapid configuration and status checking  
Rugged, weatherproof construction with an IP67 environmental rating  
–40 °C to +65 °C (–40 °F to +149 °F) operating temperature range  
9.5 V to 28 V DC input power range, with over-voltage protection  
Capable of rover operation within a VRS (Virtual Reference Station) network  
Moving baseline and heading capability when combined with an appropriate  
SPSx51, SPSx50, or SPS551H receiver  
RoHS compliant  
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Features and Functions  
2
SPS651 Receiver optional features  
Internal 450 MHz (3 frequency bands) radio with receive capability  
Internal 900 MHz radio with transmit and receive capability  
Can be upgraded to receive GLONASS signals  
Can be upgraded to receive L2C signals  
Note – When the receiver is upgraded to GLONASS, the GA510 rover GPS antenna should  
be replaced with the ZephyrModel 2 antenna.  
This receiver is ideal for site supervisors on construction and roading projects or  
marine dredging  
SPS751 features  
The SPS751 receiver provides the following standard features. For features specific to  
each model, see below.  
SPS751 standard features  
Integrated GPS receiver and radio  
450 or 900 MHz radio  
L1/L2/L2C GPS receiver  
OmniSTAR XP/HP/VBS service capable  
WAAS (Wide Area Augmentation System), EGNOS (European Geo-Stationary  
Navigation System), and MSAS Satellite Based Augmentation (SBAS)  
compatible  
Long-life integrated battery, typically provides 10 hours operation as a base  
station with internal transmit/receive radio, or 13 hours as a rover  
Configuration and monitoring interface through the following methods:  
Web interface  
Networked or peer-to-peer Ethernet  
Integrated display and keyboard  
Trimble SCS900 Site Controller software  
Integrated Bluetooth wireless technology for cable-free configuration and  
operation with a controller  
Choice of external GPS antenna for base station or rover operation  
Attached or external radio antenna for rover or high-gain base station radio  
operation  
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2
Features and Functions  
Small, lightweight design – 1.65 kg (3.64 lbs) receiver only including the battery;  
4 kg (8.82 lbs) complete system weight (rover including controller and rod)  
Permanent/semi-permanent and mobile quick setup base station capability  
Backpack, belt, rod, truck, and marine vessel mounting options for rover  
applications  
Capable of all site measurement and stakeout operations within 2.4 km (1.5 m)  
(SPS751 Basic) and typically 5 km (3.1 m) (SPS751 Max)  
Easy-to-use menu system for rapid configuration and status checking  
AutoBasetechnology for rapid and automated repeated daily base station  
setups  
Can broadcast corrections through multiple radio links from one base station,  
for example, through an internal 450 MHz radio and an external 900 MHz radio  
CAN (Controller Area Network) support  
Rugged, weatherproof construction with an IP67 environmental rating  
–40 °C to +65 °C (–40 °F to +149 °F) operating temperature range  
9.5 V to 28 V DC input power range, with over-voltage protection  
RoHS compliant  
Tracks up to 24 GPS satellites and 4 SBAS satellites  
Can receive GPS L2C signals  
1 Pulse-per-second (1PPS) output  
SPS751 Basic  
Base station only, or rover only, operation  
SPS751 Basic base  
Entry-level, low-cost RTK base station  
Unrestricted operational range for rovers and grade control systems  
Integrated transmit-only radio  
Easily upgraded to the SPS751 Max (if the SPS751 Basic base receiver is already  
fitted with an internal UHF radio, the upgrade includes the ability for the SPS751  
Max to receive signals).  
SPS751 Basic rover  
Entry-level, low cost RTK rover receiver  
2 Hz measurement update rate  
2.4 km (1.5 mile) operational range from the base station  
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Features and Functions  
2
Integrated receive-only radio  
Easily upgraded to the SPS751 Max (if the SPS751 Basic rover receiver is already  
fitted with an internal UHF radio, the upgrade includes the ability for the SPS751  
Max to transmit signals)  
This receiver is ideal for contractors new to GPS as a starter system or for operating  
multiple small projects.  
SPS751 Max  
RTK base station and rover operation in a single receiver  
Integrated receive/transmit radio  
5 Hz or 10 Hz measurement update rate  
Unrestricted rover operation range from a base station  
Operates within a Trimble VRS network, for base station-free rover capability  
Moving baseline and heading capability when any SPSx51 receiver (excluding  
the SPS551H or SPS751 Basic receiver) is combined with any SPSx51 or SPS551H  
add-on receiver.  
SPS851 features  
The SPS851 receiver provides the following features:  
Integrated GPS receiver and radio  
450 or 900 MHz radio  
72-channel L1/L2/L2C/L5 GPS plus L1/L2 GLONASS receiver  
OmniSTAR XP/HP/VBS service capable  
4-channel WAAS (Wide Area Augmentation System), EGNOS (European  
Geo-Stationary Navigation System), and MSAS Satellite Based Augmentation  
(SBAS) compatible  
Long-life integrated battery, typically provides 9 hours operation as a base  
station or 12 hours as a rover with internal transmit/receive radio  
Configuration and monitoring interface through the following methods:  
Web interface  
Networked or peer-to-peer Ethernet  
Integrated display and keyboard  
Trimble SCS900 Site Controller software  
Integrated Bluetooth wireless technology for cable-free configuration and  
operation with a controller  
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2
Features and Functions  
Choice of external GPS antenna for base station or rover operation  
Attached or external radio antenna for rover or high-gain base station operation  
Small, lightweight design – 1.65 kg (3.64 lbs) receiver only, including the battery;  
4 kg (8.82 lbs) complete system weight (rover including controller and rod)  
Permanent/semi-permanent and mobile quick setup base station capability  
Backpack, belt, rod, truck, and marine vessel mounting options for rover  
applications  
Capable of all site measurement and stakeout operations within radio or cellular  
coverage  
Easy-to-use menu system for rapid configuration and status checking  
AutoBase technology for rapid and automated repeated daily base station  
setups  
Can broadcast corrections through multiple radio links from one base station,  
for example, through an internal 450 MHz radio and an external 900 MHz radio  
or over the Internet.  
Rugged, weatherproof construction with an IP67 environmental rating  
–40 °C to +65 °C (–40 °F to +149 °F) operating temperature range  
9.5 V to 28 V DC input power range, with over-voltage protection  
Capable of rover operation within a VRS (Virtual Reference Station) network  
Moving baseline and heading capability when any SPSx51 receiver (excluding  
the SPS551H or SPS751 Basic receiver) is combined with any SPSx51 or SPS551H  
Add-on receiver.  
RoHS compliant  
1 Pulse-per-second (1PPS) output  
Note – To receive GPS L5 or GLONASS signals in the SPS851, you must purchase the  
optional upgrade.  
Base station  
Unrestricted operational range for rovers and grade control systems  
Base station and rover operation in a single receiver  
Integrated transmit/receive radio  
Rover  
5 Hz, 10 Hz, or 20 Hz measurement update rate (10 Hz maximum in Heading  
mode)  
Base station-free rover capability within a VRS network  
Base station-free rover capability using OmniSTAR services  
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Features and Functions  
2
Operates as an SBAS rover when coverage is available  
This receiver is ideal for contractors who operate mid-to-large size projects with  
machine control.  
Use and care  
This product is designed to withstand the rough treatment and tough environment  
that typically occurs in construction applications. However, the receiver is a  
high-precision electronic instrument and should be treated with reasonable care.  
CAUTION – Operating or storing the receiver outside the specified temperature range can  
damage it. For more information, see Chapter 10, Specifications.  
C
COCOM limits  
The U.S. Department of Commerce requires that all exportable GPS products contain  
performance limitations so that they cannot be used in a manner that could threaten  
the security of the United States. The following limitations are implemented on this  
product:  
Immediate access to satellite measurements and navigation results is disabled  
when the receiver velocity is computed to be greater than 1,000 knots, or its  
altitude is computed to be above 18,000 meters. The receiver GPS subsystem  
resets until the COCOM situation clears. As a result, all logging and stream  
configurations stop until the GPS subsystem is cleared.  
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2
Features and Functions  
Keypad and display  
1
4
2
3
2
Feature  
Description  
Indicates if the receiver is turned on or off.  
1
2
3
Power LED  
Buttons  
Display  
Used to turn on and configure the receiver (see Button functions, page 62).  
The receiver has a Vacuum Fluorescent Display that allows you to see how the  
receiver is operating and view the configuration settings.  
4
Bluetooth antenna Location of the Bluetooth antenna.  
Figure 2.1  
Front view of the receiver  
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Features and Functions  
2
Rear connectors  
1
2
4
5
3
Connector type  
Description  
1
2
TNC  
Connect to the GPS antenna  
• TNC (450 MHz Internal  
radio)  
Connect to the radio antenna  
• Reverse polarity TNC  
(900 MHz internal radio)  
• Not installed, system without  
internal radio  
3
4
Vent plug  
External venting plug for pressure equalization  
High Density  
DB26  
• Ethernet connectivity to a 10/100 Base-T network through an  
RJ45 jack on a multiport adaptor (P/N 57167)  
• 'Slave' USB communications through the USB type B  
connector on the multiport adaptor (P/N 57167)  
• 'Host' USB communications through the USB type A  
connector on the 26-pin to Hirose adaptor (P/N 56653-10) and  
Hirose to USB type A cable (P/N 73841001)  
• Primary power from a Trimble AC/DC power supply  
(P/N 62546) using the multiport adaptor (P/N 57167)  
• Power input from an SPS700 total station battery cradle  
system using the adaptor (P/N 56653-10)  
• Full 9-wire RS-232 serial communications using the 26-9-pin  
multiport adaptor (P/N 57168) or a 26-pin serial  
communications cable  
• 1PPS, 2 x RS-232 input DC, USB, Ethernet cable (P/N 60789-00)  
5
Lemo (7-pin/0-shell)  
• 3 wire RS-232 serial communications using a 7-pin/ 0 shell  
Lemo cable  
• Secondary power from a Trimble battery (P/N 32364-00 or  
32365-00) or a 12 V battery using the Fused Lemo Power  
Cable (P/N 46125-20)  
• CAN  
Figure 2.2  
Rear view of the receiver  
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2
Features and Functions  
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C H A P T E R  
3
Batteries and Power  
3
In this chapter:  
The GPS receiver uses an internal rechargeable  
Lithium-ion battery, which can be replaced only  
at an Authorized Trimble Service Center.  
The receiver can also be powered by an external  
power source that is connected to the Lemo or  
modem port.  
The operational time provided by the internal  
battery depends on the type of measurement and  
operating conditions. Typically, the internal  
battery provides 10 hours operation as a base  
station and 12 hours as a rover during  
measurement operations using the internal  
radio.  
Note – All battery operation tests are carried out  
with new, fully charged batteries at room  
temperature and full receiver configuration  
operational. Older batteries, at temperatures  
significantly higher or lower than room  
temperature, will have a reduced performance.  
Receivers operating with reduced configuration will  
have a higher performance.  
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3
Batteries and Power  
External power  
The GPS receiver uses an external power source in preference to its internal batteries.  
If the receiver is not connected to an external power source, or if the external power  
supply fails, the internal batteries are used.  
While carrying out static measurements for postprocessed computations using the  
internal memory, if no external power is supplied and the internal battery is drained,  
the receiver shuts down. No data is lost and when power is restored, the receiver  
restarts in the same status as it was when power was lost.  
It is possible to turn off the internal battery using the web interface. In this case, when  
external power is switched off, there is a limited time (30 seconds) before the unit turns  
off.  
Battery safety  
The receiver is powered by a rechargable internal Lithium-ion battery. Charge and use  
the battery only in strict accordance with the instructions below.  
WARNING – Do not damage the rechargeable Lithium-ion battery. A damaged battery  
can cause an explosion or fire, and can result in personal injury and/or property damage.  
To prevent injury or damage:  
C
– Do not use or charge the battery if it appears to be damaged. Signs of damage include,  
but are not limited to, discoloration, warping, and leaking battery fluid.  
– Do not expose the battery to fire, high temperature, or direct sunlight.  
– Do not immerse the battery in water.  
– Do not use or store the battery inside a vehicle during hot weather.  
– Do not drop or puncture the battery.  
– Do not open the battery or short-circuit its contacts.  
WARNING – Avoid contact with the rechargeable Lithium-ion battery if it appears to be  
leaking. Battery fluid is corrosive, and contact with it can result in personal injury and/or  
property damage.  
C
To prevent injury or damage:  
– If the battery leaks, avoid contact with the battery fluid.  
– If battery fluid gets into your eyes, immediately rinse your eyes with clean water and  
seek medical attention. Do not rub your eyes!  
– If battery fluid gets onto your skin or clothing, immediately use clean water to wash off  
the battery fluid.  
Battery performance  
To optimize battery performance and extend battery life:  
Fully charge all new batteries before use.  
Batteries perform best when they are not used at extreme temperatures. The  
receiver is designed to operate at –40 °C to +65 °C (–40 °F to +149 °F). However,  
operation at temperatures of less than 0 °C (32 °F) can cause a rapid drop in  
battery life.  
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Batteries and Power  
3
The Lithium-ion batteries are rated to operate from –20 °C to +60 °C (–4 °F to  
+140 °F)  
Do not allow a battery that is in storage to discharge to below 5 V.  
Charging the Lithium-ion battery  
The rechargeable Lithium-ion battery is supplied partially charged. Charge the battery  
completely before using it for the first time. If the battery has been stored for longer  
than three months, charge it before use.  
The internal battery charges fully in 8 hours when connected to a suitable power  
source.  
WARNING – Charge and use the rechargeable Lithium-ion battery only in strict  
accordance with the instructions. Charging or using the battery in unauthorized  
equipment can cause an explosion or fire, and can result in personal injury and/or  
equipment damage.  
C
To prevent injury or damage:  
– Do not charge or use the battery if it appears to be damaged or leaking.  
– Charge the Lithium-ion battery only with a Trimble product that is specified to charge it.  
Be sure to follow all instructions that are provided with the battery charger.  
– Discontinue charging a battery that gives off extreme heat or a burning odor.  
– Use the battery only in Trimble equipment that is specified to use it.  
– Use the battery only for its intended use and according to the instructions in the product  
documentation.  
When the internal temperature of the receiver is greater than 50 °C (122 °F) or less than  
5 °C (41 °F), the internal battery charger stops charging and the receiver’s display  
shows Charger Disabled, Temp Limited. However, the receiver will still draw its power  
from the external DC source, extending the operating time in the field.  
When the external DC voltage is less than 15 V DC, an X is displayed across the battery  
status icon on the front panel display, which indicates that the internal charger is off.  
Storing the Lithium-ion battery  
If you must store a Lithium-ion battery for long periods, make sure that it is fully  
charged before it is stored, and that you charge it at least once every three months  
while it is stored.  
Do not allow a battery that is in storage to discharge to below 5 V. A battery that  
reaches deep discharge level (5 V or less) cannot be recharged and must be replaced.  
(To protect a battery that is in use from deep discharge, the receiver switches power  
sources or stops drawing power when the battery pack discharges to 5.9 V.)  
All batteries discharge over time when not in use, and they discharge faster in colder  
temperatures. Do not store the receiver at temperatures outside the range –40 °C to  
+70 °C (–40 °F to +158 °F).  
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3
Batteries and Power  
Using the Lithium-ion battery as a Universal Power Supply  
(UPS)  
The receiver has an internal Lithium-ion battery. The internal battery will only charge  
from an external power source that delivers more than 15 volts, for example, an AC  
power adaptor. The receiver is supplied with a mains power supply unit that recharges  
the battery inside the receiver when it is connected through the adaptor to the modem  
port or the Lemo port. When you use the receiver on large projects, from a permanent  
or semi-permanent base station location in a site trailer, Trimble recommends that  
you use this power supply at all times to keep the internal battery charged. This  
provides an uninterrupted power supply and will keep the site operational for more  
than 10 hours after a power failure.  
Keep all batteries on continuous charge when not in use. You can keep batteries on  
charge indefinitely without damage to the receiver or to the batteries.  
Removing the rechargeable Lithium-ion battery  
The internal Lithium-ion battery should be removed only at an authorized Trimble  
Service Center. If the battery is removed at an unauthorized service center, the  
remaining warranty on the product will be void.  
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C H A P T E R  
4
Setup Guidelines  
4
In this chapter:  
GPS Real-Time Kinematic (RTK) operation  
provides centimeter-level accuracy by  
eliminating errors that are present in the GPS  
system. For all RTK operations, you require both  
a base station and a rover receiver.  
This chapter introduces the concepts of base  
station and rover operation, provides  
information to help you identify good setup  
locations, describes best practices for setting up  
the equipment, and outlines the precautions that  
you need to take to protect the equipment.  
Note – This chapter provides setup information for  
all the receivers in the SPS GPS receiver family.  
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4
Setup Guidelines  
Base station operation guidelines  
A base station consists of a receiver that is placed at a known (and fixed) position. The  
receiver tracks the same satellites that are being tracked by the rover receiver, at the  
same time that the rover is tracking them. Errors in the GPS system are monitored at  
the fixed (and known) base station, and a series of position corrections are computed.  
The messages are sent through a radio link to the rover receiver, where they are used to  
correct the real time positions of the rover.  
Base station components  
The base station has the following components:  
GPS receiver  
GPS antenna  
Base station radio  
Power supply  
GPS receiver and GPS antenna  
The base station GPS receiver can be one of following types:  
A Smart GPS antenna, such as the SPSx81, which incorporates a GPS receiver,  
GPS antenna, power supply, and radio into a single compact unit. A Smart GPS  
antenna can be rapidly set up on a tripod, fixed height tripod, or T-Bar anywhere  
that is convenient on the jobsite.  
A Modular GPS receiver, such as the SPSx51, which incorporates a GPS receiver,  
power supply, and radio in a single unit. The GPS antenna (and, optionally, the  
base station radio antenna) is separate from the receiver. Because the GPS  
antenna is separate, you can use the following optimized components:  
a geodetic antenna with large ground plane, to eliminate multipath (the  
major source of GPS errors) at the base station  
a high-gain or directional radio antenna, to increase broadcast range and to  
provide maximum coverage  
You can also place a modular GPS receiver in an easily accessible and secure  
location, safe from theft and the weather, while the antennas are placed high on  
a tower or building, clear of obstructions and able to deliver maximum  
performance.  
You can use either type of receiver in a permanent, semi-permanent, or daily quick  
setup configuration. If semi-permanent or permanent operation is required, however,  
the modular receiver delivers significant advantages.  
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Setup Guidelines  
4
Base station setup guidelines  
For good performance, observe the following base station setup guidelines:  
Place the GPS receiver in a location on the jobsite where equal range in all  
directions provides full coverage of the site. This is more important on larger  
jobsites, where the broadcast range of the base station radio may limit the  
operations of the GPS system.  
Place the GPS antenna in a location that has a clear line of sight to the sky in all  
directions. Do not place the GPS antenna near vertical obstructions such as  
buildings, deep cuttings, site vehicles, towers, or tree canopy.  
Place the GPS and radio antennas as high as practical. This minimizes  
multipath from the surrounding area, and enables the radio to broadcast to the  
maximum distance.  
Note – The GPS antenna must have a clear line of sight to the sky at all times during  
operation.  
Choose the most appropriate radio antenna for the size and footprint of the site.  
The higher the gain on the antenna, the longer the range. If there is more focus  
on the transmission signal, there is a reduced coverage area. A 3 db or 5 db gain  
antenna provides a mix of good range and reasonable directional coverage.  
Make sure that the GPS receiver does not lose power. The GPS receiver has an  
integrated battery, which has to be charged. To operate continuously for more  
than a day without loss of power at the base station, provide external power.  
Sources of external power include:  
AC power  
12 V car or truck battery  
Trimble custom external battery pack  
Generator power  
Solar panel  
When you use an external power supply, the integrated battery provides a  
backup power supply, enabling you to maintain continuous operation through a  
mains power failure.  
When the GPS receiver is connected to a power source greater than 15 V, the  
integrated battery is continuously charged from the connected power source.  
This helps to ensure that the battery stays charged (SPSx51 only).  
Do not locate a GPS receiver, GPS antenna, or radio antenna within 400 meters  
(about 1,300 feet) of:  
a powerful radar, television, or cellular communications tower  
another transmitter  
another GPS antenna  
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4
Setup Guidelines  
Cell phone towers can interfere with the base station radio broadcast and can  
stop corrections from reaching the rover receiver. High-power signals from a  
nearby radio or radar transmitter can overwhelm the receiver circuits. This does  
not harm the receiver, but can prevent the receiver electronics from functioning  
correctly.  
Low-power transmitters, such as those in cell phones and two-way radios, do  
not interfere with receiver operations.  
Do not set up the base station directly beneath or close to overhead power lines  
or electrical generation facilities. The electromagnetic fields associated with  
these utilities can interfere with GPS receiver operation. Other sources of  
electromagnetic interference include:  
Gasoline engines (spark plugs)  
Televisions and computer monitors  
Alternators and generators  
Electric motors  
Equipment with DC-to-AC converters  
Fluorescent lights  
Switching power supplies  
Place the GPS receivers in a protected and secure location. If the base station is  
in the center of a jobsite where heavy machinery is operating, place flags around  
the base station to warn operators of its existence.  
If you place the SPSx51 Modular GPS receiver in a lock box on the jobsite to  
protect the receiver from theft or from the weather, shield the lock box from  
direct sunlight and provide ventilation for the receiver through an inlet and  
extractor fan. A receiver that has a broadcast radio generates significant heat.  
Do not allow the temperature in the box to exceed 50 ºC (122 ºF).  
If working in a cold climate, you may need to provide heat to the receiver. Do not  
operate the receiver below –40 ºC (–40 ºF).  
Trimble recommends that, wherever possible, you keep GPS receiver equipment  
dry. The receivers are designed to withstand wet weather, but keeping them dry  
prolongs their life and reduces the effects of corrosion on ports and connectors.  
If the equipment gets wet, use a clean dry cloth to dry the equipment and then  
leave the equipment open to the air to dry. Do not lock wet equipment in a  
transport case for prolonged periods. Avoid exposing the GPS receiver to  
corrosive liquids and salt water wherever possible.  
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Setup Guidelines  
4
Trimble recommends that you install lightning protection equipment at  
permanent base station locations. Equipment should include a gas capsule  
lightning protector in the GPS and radio antenna feed line and appropriate  
safety grounding. A static dissipater near the antennas can reduce the likelihood  
of a direct lightning strike. Also protect any communications and power lines at  
building entry points. For more information, contact your local Trimble dealer,  
or go to the Huber and Suhner website (www.hubersuhnerinc.com).  
Trimble recommends that you use surge protection equipment on all  
permanently installed equipment.  
Permanent installation antenna cabling for the SPSx51 Modular GPS  
receiver  
Many permanent base station installations have unique cabling requirements.  
Depending on the available infrastructure, you may need to mount the antenna a  
considerable distance from the receiver.  
The SPSx51 can withstand a loss of 12 dB between the GPS antenna and the receiver.  
The degree of loss in a coaxial cable depends on the frequency of the signal passing  
through it. Table 4.1 lists some common cable types and the maximum length you can  
use before an inline amplifier for GPS frequencies is required.  
Table 4.1  
Maximum cable lengths  
Maximum length (for use without an inline amplifier)  
Cable type  
RG-214  
30 m (100 ft)  
70 m (230 ft)  
85 m (280 ft)  
106 m (350 ft)  
165 m (540 ft)  
225 m (740 ft)  
LMR-400  
LMR-500  
LMR-600  
Heliax LDF4/50  
Heliax LDF4.5/40  
Rover operation guidelines  
The second part of the RTK GPS system is the rover receiver.  
The rover receiver is mounted on a pole, vehicle, marine vessel, or in a backpack, and is  
moved between the points that require measurement or stakeout. The rover receiver is  
connected to a base station or to a source of RTK corrections such as a virtual  
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4
Setup Guidelines  
reference station system. The connection is provided by an integrated radio, a cellular  
modem in the controller, or through an external cellular phone that is connected to  
the receiver either by Bluetooth wireless technology or by means of a cable.  
The correction stream for some other positioning solutions, such as SBAS  
(WAAS/EGNOS/MSAS) and the OmniSTAR service1, is broadcast through  
geostationary satellites, and detected by the GPS antenna itself. No integrated radio or  
base station is required.  
Rover receiver components  
The rover receiver has the following components:  
GPS receiver  
GPS antenna  
Optional integrated radio receiver and antenna for RTK operations  
Optional items for the different mounting options (see below)  
In most rover applications, the receiver operates entirely from its own integrated  
battery unit. On a vehicle or on a marine vessel, however, an external power supply can  
be used. Use an external power supply if one is provided. The internal battery then acts  
as a uninterruptible power supply, covering any external power failures.  
Choose a rover receiver according to the needs of the job:  
A Smart GPS antenna, such as the SPSx81, incorporates the GPS receiver, GPS  
antenna, power supply, and receive radio into a single compact unit. A Smart  
GPS antenna can be rapidly set up on a pole, vehicle, or backpack. This makes it  
easy to carry when you are measuring around the jobsite.  
A Modular GPS receiver, such as the SPSx51, incorporates the GPS receiver,  
receive radio, and power supply into a single unit. The GPS antenna and,  
optionally, the receive radio antenna, is separate from the receiver. When you  
use a modular GPS receiver as a rover, you can use optimized components  
placed in the best locations for your application. For example:  
A small, lightweight rover antenna can be mounted on a pole or backpack;  
placed in a high, inaccessible location on a marine vessel mast or cabin; or  
placed on a site vehicle roof or truck bed.  
A rubber duck radio antenna, or an external radio antenna, can be  
mounted on a vehicle or vessel roof to provide maximum coverage.  
A Modular GPS receiver can be placed in a location that is both easily accessible  
and safe from theft and the weather. The antennas can be placed high on a  
vehicle or vessel roof, clear of obstructions and able to deliver maximum  
performance.  
1.  
OmniSTAR is available only with the SPSx51 Modular GPS receivers.  
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Setup Guidelines  
4
Rover receiver setup guidelines  
For good rover operation, observe the following setup guidelines:  
Place the GPS antenna in a location that has a clear line of sight to the sky in all  
directions. Do not place the antenna near vertical obstructions such as  
buildings, deep cuttings, site vehicles, towers, or tree canopy. GPS rovers and the  
base station receive the same satellite signals from the same satellites. The  
system needs five common satellites to provide RTK positioning.  
Place the GPS and radio antennas as high as possible to minimize multipath  
from the surrounding area. The receiver must have a clear line of sight to the sky  
at all times during operation.  
GPS satellites are constantly moving. Because you cannot measure at a specific  
location now does not mean that you will not be able to measure there later,  
when satellite coverage at the location improves. Use GPS planning software to  
identify the daily best and worst satellite coverage times for your location and  
then choose measurement times that coincide with optimal GPS performance.  
This is especially important when operating in the worst GPS locations. The  
Trimble Planning software is on the Trimble SPS GPS Receiver CD included with  
the receiver. You can also download the Trimble Planning software from the  
The SPS851/SPS751 can track the GPS L2C modernization signal. Additionally,  
the SPS851 can optionally track the GPS L5 modernization signal and some  
receivers can also track the GLONASS satellite constellation ( for more  
information, see GPS satellite signal tracking, page 114). These signals help you  
to get positions at the worst times of the day and in the worst GPS locations, but  
do not guarantee that you will.  
To get a fixed position solution with centimeter accuracy, initialize the rover  
receiver. For initialization to take place, the receiver must track at least five  
satellites that the base station is also tracking. In a dual-satellite constellation  
operation, for example, GPS and GLONASS, the receiver must track at least six  
satellites.  
To maintain a fixed position solution, the rover must continuously track at least  
four satellites that the base station is also tracking. In a dual-satellite  
constellation operation, for example, GPS and GLONASS, the receiver must  
track at least five satellites.The radio link between the base and rover receivers  
must also be maintained.  
Loss of the satellite signals or loss of the radio link results in a loss of centimeter  
position accuracy. From Fixed, the receiver changes to Float or Autonomous  
mode:  
In Float mode, the rover has connection to the base station through a radio,  
but has not yet initialized.  
In Autonomous mode, the rover has lost radio contact with the base  
station receiver, and is working by itself with the available GPS signals.  
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4
Setup Guidelines  
On a vehicle or marine vessel, place the GPS antenna in a location as free from  
shock and vibration as possible. For the modular GPS receivers, a single  
magnetic mount is normally sufficient to hold the antenna in a suitable  
location, whereas for the larger smart antenna, a triple magnetic mount is  
normally recommended. Good alternatives include a 5/8" thread bolt in a  
suitable location on the roof bars, or a door-mounted pole bracket.  
To mount the modular GPS receiver on a pole, use two pole mounting brackets  
and a second tripod clip (P/N 571 204 300). See Figure 4.1.  
Figure 4.1  
Rod mount for a modular GPS receiver  
To mount the modular GPS receiver on a marine vessel, use the receiver bracket  
(P/N 56830-00). For marine moving base and heading applications, use the  
receiver bracket to mount two receivers together.  
Make sure that the rover receiver does not lose power. An SPSx51 is typically  
powered by its internal battery. You cannot change the battery, but the charge  
typically lasts for longer than a working day. If you do not use the rover receiver  
very often, ensure that it is charged at least every three months. For vehicle  
operation or marine vessel operation, Trimble recommends that you use an  
external power source so that the internal battery can be saved for times when  
the receiver is being used off the vehicle or vessel.  
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Setup Guidelines  
4
Do not locate the receiver or antenna within 400 meters (about 1,300 ft) of  
powerful radar, television, cellular communications tower, or other transmitters  
or GPS antennas. Low-power transmitters, such as those in cellular phones and  
two-way radios, normally do not interfere with receiver operations. Cellular  
communication towers can interfere with the radio and can interfere with GPS  
signals entering the receiver. This does not harm the receiver, but it can prevent  
the receiver electronics from functioning correctly.  
Do not use the rover receiver directly beneath or close to overhead power lines  
or electrical generation facilities. The electromagnetic fields associated with  
these utilities can interfere with GPS receiver operation. Other sources of  
electromagnetic interference include:  
gasoline engines (spark plugs)  
televisions and computer monitors  
alternators and generators  
electric motors  
equipment with DC-to-AC converters  
fluorescent lights  
switching power supplies  
Trimble recommends that, wherever possible, all GPS receiver equipment is  
protected from rain or water. Although, the receivers are designed to withstand  
all wet weather conditions, keeping the receivers dry prolongs the life of the  
equipment and reduces the effects of corrosion on ports and connectors. If the  
equipment gets wet, use a clean dry cloth to dry the equipment and then leave  
the equipment open to the air to dry. Do not lock wet equipment in a transport  
case for prolonged periods. Wherever possible, avoid exposing the GPS receiver  
to corrosive liquids and salt water.  
If you are using the rover receiver in open spaces, Trimble recommends that you  
stop work during electrical storms where the risk of lightning strike is high.  
Where cables are involved, Trimble recommends that you use cable ties to  
secure the cables to the rod or other equipment to avoid inadvertent snagging  
while moving about the jobsite. Be careful not to kink, twist, or unnecessarily  
extend cables, and avoid trapping them in vehicle doors or windows. Damage to  
cables can reduce the performance of GPS equipment.  
Internal radio setup for rover operations  
The internal radio of the SPS GPS receiver is delivered with the transmit (Tx) radio  
frequencies preprogrammed into the receiver. To add receive (Rx) radio frequencies to  
450 MHz radios, use the WinFlash utility or web interface (see Appendix C, Adding  
UHF Internal Radio Frequencies). Network channels can be selected for the 900 MHz  
radios.  
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4
Setup Guidelines  
Once the radio frequencies are configured, use the controller or receiver to select  
channel frequencies during base station or rover setup operations.  
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C H A P T E R  
5
Setting up the Receiver  
5
In this chapter:  
This chapter provides guidelines for setting up  
the receiver as a base station, or as a rover  
receiver in a range of common use scenarios.  
This chapter also describes the procedure for  
setting up a pair of receivers for heading and  
moving base marine construction applications.  
Note – This chapter provides setup information for  
all the receivers in the SPS GPS receiver family.  
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5
Setting up the Receiver  
Connecting the receiver to external devices  
You can connect an SPSx51 Modular GPS receiver to the following devices:  
a Trimble controller running Trimble SCS900 Site Controller software  
an external radio-modem  
HYDROpro software  
Trimble controller with SCS900 Site Controller software  
You can operate an SPS GPS receiver with any Trimble controller, for example, a TSC2®  
or Trimble CU controller, that is running the SCS900 software. Typically, the receiver  
and the controller operate from their own individual power sources. The receiver and  
controller can communicate through Bluetooth wireless technology and can be  
connected without a cable. However, if a cable is required, Table 5.1 shows how to  
connect the cables for each combination of SPS GPS receiver and Trimble controller.  
Table 5.1 Connecting to a Trimble controller running the SCS900 Site Controller software  
To connect a  
Use cable part number … Use this cable connector … and connect the cable to …  
SPSx51 Modular GPS receiver to a …  
TSC2  
DB9  
TSC2  
59046  
Lemo  
SPSx51  
TSC2  
DB9  
59043  
DB9  
SPSx51  
TCU  
TCU  
6-pin Hirose  
Lemo  
53004007  
SPSx51  
TCU  
6-pin Hirose  
DB9  
53002007  
SPSx51  
TSCe  
TSCe™  
1
Lemo  
31288-xx  
Lemo  
SPSx51  
ACU  
ACU  
4-pin Hirose  
Lemo  
44147  
SPSx51  
1This cable is available in different lengths. The -xx indicates the length of the cable, in meters.  
External radio-modems  
The most common data link for Real-Time Kinematic (RTK) operation is a radio. The  
receiver is available with the following internal radios:  
410–430 MHz (Tx/Rx, Rx only, or Tx only)  
430–450 MHz (Tx/Rx, Rx only, or Tx only)  
450–470 MHz (Tx/Rx, Rx only, or Tx only)  
900 MHz (Tx/Rx, Rx only, or Tx only)  
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Note – “Tx” indicates that the radio transmits corrections. “Rx” indicates that the receiver  
receives corrections. “Tx/Rx” indicates that the radio both transmits and receives  
corrections.  
If the receiver does not have an internal transmit radio, or you want to connect to  
higher power or to a secondary external transmit radio or cellular modem, use the  
26-pin port, the Lemo port, or Bluetooth wireless technology.  
The receiver supports the following Trimble base radios:  
SiteNet450  
TRIMMARK™  
TRIMTALK450  
Trimble SNB900  
Trimble PDL450  
Trimble HPB450  
3
The receiver also supports third-party transparent radios and third-party cellular  
modems.  
When used with an SPSx51 GPS receiver, most external radios require an external  
power source. Only the Trimble SNB900 radio-modem has an internal battery and does  
not require external power.  
Configure the external radio separately, using either the configuration program for the  
external radio or the radio display and keypad.  
To configure the receiver for RTK operation, follow the base setup procedure to set the  
following parameters:  
Set the base station coordinates  
Enable the RTCM or CMR+corrections stream on the selected serial port.  
Common ways to set up a base station  
You can set up a base station in different ways depending on the application, coverage  
area, degree of permanence versus mobility, and available infrastructure. Before you set  
up a base station, please read Chapter 4, Setup Guidelines.  
Setting up a base station for permanent or semi-permanent installation  
For construction applications, where machine and site positioning operations using  
GPS will be carried out over a long time (weeks, months, or years), ensure that you  
choose the base station location carefully.  
A semi-permanent or permanent base station helps to eliminate the types of error that  
can result from repeated daily setups, and ensures that you always use the GPS  
antenna at the exact original location. The requirement for a permanent base station  
setup increases as more receivers that use the base station as a source of corrections,  
increases the cost of any base station downtime.  
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5
Setting up the Receiver  
On the largest jobsites, and on those that remain operational for the longest time, a  
permanent or semi-permanent installation is a popular solution. A modular GPS  
receiver is typically used as the base station, located in a site office or trailer where it is  
easy to access (to check or configure), and where it is secure from theft and the  
weather. The GPS and radio antennas are normally mounted on a permanent structure  
on the roof of the building, where they are high and clear from obstructions and where  
the radio antenna can provide the maximum range of operation.  
Trimble recommends that you use the Trimble Zephyr GeodeticModel 2 GPS  
antenna. This antenna has a large ground plane that reduces multipath, providing the  
best GPS performance at the base location. The antennas are connected to the receiver  
by high quality RF cables.  
The receiver is connected to a permanent power supply (mains or generator power).  
The internal battery of the receiver is always being charged, and acts as an  
uninterruptible power supply if there is a power failure. In some cases, the receiver may  
also be connected by an Ethernet cable to the Internet, so that it can be monitored and  
configured from a remote location, and can warn an administrator by email or text  
message if there is a change to the configuration or status. In these situations, the  
receiver can transmit GPS RTK corrections to a remote radio or receiver over the  
Internet, for rebroadcast requirements, without using repeaters.  
Figure 5.1  
SPSx51 receiver permanent installation  
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Setting up the Receiver  
5
Setting up a base station for daily site use: T-Bar  
For construction applications where a daily setup and takedown of equipment is  
required for security reasons, Trimble recommends that you use a T-Bar setup.  
The T-Bar consists of a post mounted in concrete (so it cannot move), which has a  
solid metal T-Bar mounted to it to provide lateral and vertical separation between the  
GPS antenna and radio antenna. The T piece of the T-Bar has a vertical rod at each  
end. Each end terminates in a 5/8"×11 thread to which the antennas can be mounted.  
Trimble recommends that one end is clearly marked GPS and the other end is clearly  
marked Radio so that at each daily setup, the GPS and radio antennas are mounted at  
the same location. Switching antennas by mistake introduces a position error in all  
resulting measurements. You can buy the parts you need to make a T-Bar from any  
reputable hardware store. Make certain that the T-Bar cannot rotate after  
construction. Rotation of the T-Bar can introduce a position error into all subsequent  
measurements.  
On the upright post, mount either a bracket (to which the GPS receiver can be  
mounted), or a well-ventilated lockbox (in which the GPS receiver itself can be  
secured).  
Each day, mount the GPS antenna on the GPS end of the T-Bar and the radio antenna  
on the Radio end of the T-Bar. Connect the antennas to the receiver using the  
appropriate cables.The receiver uses its own integrated battery, or an external 12 V  
battery through the 12 V crocodile clips cable that are provided with the receiver. If you  
choose to use AC power, remember that the heat generated by the charging process  
and the radio transmitter increases the need for good ventilation around the receiver.  
In such scenarios, an SPSx81 Smart GPS antenna is also often used. Simply mount the  
SPSx81 on the T-Bar, and optionally connect to an external battery or radio unit.  
Advantages  
Use of a T-Bar setup ensures that the base station is set up with exactly the same  
position and height every day. This helps eliminate the errors typically associated with  
daily tripod setup. For example, wrong antenna height, base not set up over the point,  
base set up in the wrong location.  
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5
Setting up the Receiver  
Radio  
GPS  
Figure 5.2  
System set up on a T-bar showing an external radio antenna to gain longer  
range  
Setting up a mobile base station: Tripod and fixed height tripod  
If you are repeatedly moving between jobsites, or if you are visiting a jobsite for the first  
time before a T-Bar or similar setup can be established, Trimble recommends that you  
use either a tripod and tribrach setup, or a fixed height tripod.  
The fixed height tripod is quicker and easier to set up over a control point. It allows you  
to re-establish the antenna height exactly so that the receiver can be set up faster  
without using the SCS900 software or without needing to enter a revised antenna  
height in the receiver front panel. Take great care to ensure that the GPS antenna is set  
up accurately over the control point, and that the GPS antenna height is measured  
accurately, in the right way (vertical or slope height) to the right location on the  
antenna (base of antenna or to a specified location on the antenna). When you start  
the rover receiver, it is extremely important to check in, at one or more known  
locations, to check for possible position or height errors. Checking in at a known  
location is good practice and can avoid costly errors caused by a bad setup.  
Typically, the tripod and fixed height tripod methods do not give significant height  
clearance above the ground, and can reduce the range of operation caused by radio  
limitations.  
Tripod and tribrach setup  
In the tripod setup, the tripod is located over the control point, and the tribrach and  
tribrach adaptor is mounted on the tripod and centered over the point.  
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Setting up the Receiver  
5
1. Mount the GPS antenna on the tribrach adaptor.  
2. Clip the GPS receiver to the tripod.  
3. Connect the GPS antenna to the receiver using the appropriate cable.  
4. If necessary, connect the GPS receiver to an external 12 V power supply. Use the  
crocodile clip cable or the Trimble custom power pack.  
SPSx51 with a low-gain “rubber  
duck” antenna  
SPSx51 with an external  
high-gain antenna  
SPSx81 with an internal 450 MHz  
Tx radio  
Figure 5.3  
Tripod and tribrach setup  
Fixed height tripod setup  
A fixed height tripod setup is similar to a tripod setup, but is simplified by the central  
leg of the tripod, that is placed directly on the control point. If the central leg is leveled  
accurately, the fixed height tripod is quick and easy to set up, and provides an accurate  
way to measure the true antenna height.  
1. Set up the tripod over the control point.  
2. Attach the GPS antenna to the head of the tripod.  
3. If using an external high-gain radio antenna, mount the radio antenna to the  
radio antenna bracket that is attached to the head of the tripod (beneath the  
GPS antenna). See Figure 5.4.  
4. Hook the receiver to the center leg of the tripod, using the tripod clip.  
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Setting up the Receiver  
Radio antenna bracket  
SPSx51 with a low-gain “rubber  
duck” antenna  
SPSx51 with an external  
high-gain radio antenna  
SPSx81 with an internal 450 MHz Tx  
radio on a fixed height tripod  
Figure 5.4  
Fixed height tripod setup  
Common ways to set up a rover receiver  
You can set up a rover receiver in different ways depending on the application. The  
components that make up a rover receiver are:  
GPS receiver  
GPS antenna  
controller/computer  
rod mounting equipment, including a rod, receiver bracket, and controller  
bracket  
vehicle mounting equipment, including a suction cup and ball joint, extension  
arm, controller bracket, magnetic antenna mount, and necessary cables.  
backpack equipment, including backpack and antenna-mounting rod  
marine vessel mounting equipment, including receiver bracket, cables, antenna,  
and radio antenna brackets  
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Setting up the Receiver  
5
Setting up the rover receiver on a jobsite vehicle  
CAUTION – This following rover setup is suited only to offroad (jobsite) vehicle use. Do  
not use this method on a vehicle that is driven at speed or in traffic.  
C
1. Mount the GPS antenna for the receiver on the roof of the vehicle. Use a single  
magnetic mount or a 5/8"×11 thread bolt attached to the roof bars. Run the GPS  
antenna cable for the receiver into the vehicle either through a rubber grommet  
in the roof, or through the passenger door window, which needs to be left  
slightly open during operation.  
2. Place and secure the GPS receiver in a convenient location in the vehicle.  
The GPS receiver can be controlled through the controller connected using  
Bluetooth wireless technology.  
If the receiver is not connected to vehicle power, then the receiver needs to be  
accessed only to turn it on at the start of each measurement session. It may be  
more convenient if the SPSx51 is placed in a location where the vehicle operator  
can see the keypad and display, to monitor receiver status and to configure  
settings as required. Most receiver capability can be controlled using the SCS900  
Site Controller software.  
3. Attach the suction cup to the front windscreen, dashboard, or other convenient  
location in the vehicle, making sure that it does not obstruct the driver’s view.  
4. Attach the RAM extension arm to the suction cup, and the controller bracket to  
the RAM extension arm.  
5. Lock the controller into the controller bracket and then adjust the bracket until  
the controller is in the most convenient location. Make sure that the controller  
does not restrict visibility through the front windscreen during vehicle use.  
6. Lock the brackets so that the controller is held securely. If required, connect  
either the GPS receiver or the controller to an in-vehicle power supply as  
needed.  
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5
Setting up the Receiver  
Figure 5.5  
Configuring an SPSx51 from the cab. A Zephyr Model 2 antenna is mounted  
on the roof.  
Setting up the rover receiver on a rod  
For rod-based operation, mount the SPSx51 Modular  
GPS receiver as follows:  
1. Mount the two rod brackets on the rod.  
2. Tighten the top bracket, making sure that it is at  
a convenient height for the receiver.  
3. Place the receiver in the slot in the rod bracket,  
and secure with the tripod clip.  
4. Move the lower rod bracket down until it is over  
the second tripod clip on the receiver and then  
tighten the rod bracket onto the rod. The  
receiver is held in place between the two  
brackets.  
5. Insert the controller into the controller bracket  
as shown opposite.  
6. Use the 5/8" thread to attach the GPS antenna to  
the top of the rod.  
7. Use the GPS antenna cable to connect GPS  
antenna to the receiver.  
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Setting up the Receiver  
5
Setting up a rover receiver on a belt or in a backpack  
If you prefer to work free of the weight of the receiver on a pole, you can mount the  
rover receiver on a belt (SPSx51 only) or carry it in/on a backpack (all receivers). When  
you wear the receiver on a belt, ensure that the display is always visible so that you can  
easily check the status of the receiver. If you carry the receiver in a backpack, use an  
external radio antenna mount to allow for optimal radio signal reception. If you use a  
low-gain antenna mounted directly on the receiver in a backpack, it may affect the  
radio signal reception and reduce the likelihood of obtaining an RTK Fixed solution.  
Setting up a pair of GPS receivers to provide heading  
The SPS551H receiver is permanently in Heading mode and, when combined with a  
suitable Trimble receiver, provides GPS heading. Other SPSx51 GPS receivers can also  
be paired for heading output if they can operate in Heading mode (see Configuring the  
The SPS551H is a dual-frequency GPS receiver with a dual-frequency antenna, but it  
does not operate as a stand-alone DGPS receiver. To compute a true north heading and  
to be capable of positioning, the receiver requires an output message from another  
SPSx51 receiver. To determine the precise vector between two moving objects, pair the  
SPS551H Heading add-on with any one of the following receivers:  
SPS551  
SPS751 Max  
SPS851  
Connect the antenna on the SPS551H to the other receiver to determine the precise  
GPS heading between the two antennas. The SPS551H GPS receiver show the heading  
on the two-line display, and outputs the heading data in NMEA or binary format.  
Tip – To create a single, compact GPS position and heading unit, use the mounting frame  
provided to stack the SPS551H GPS receiver on top of the other GPS receiver. See below.  
Use the Marine Heading Cable (P/N 57169-10) provided.  
B
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5
Setting up the Receiver  
The Moving Baseline RTK positioning technique  
In most RTK applications, the reference receiver remains stationary at a known  
location and the rover receiver can move. However, Moving Baseline RTK is an RTK  
positioning technique in which both reference and rover receivers can move about.  
Moving Baseline RTK is useful for GPS applications that require vessel orientation.  
Antenna  
Antenna  
Figure 5.6  
Vessel heading from Moving Baseline RTK  
With Moving Baseline RTK, the reference receiver broadcasts Compact Measurement  
Record (CMR) data, while the rover receiver performs a synchronized baseline solution  
at 10 Hz. The resultant baseline solution has centimeter-level accuracy. To increase the  
accuracy of the absolute location of the two antennas, the Moving Reference receiver  
can use differential corrections from a static source, such as a shore-based reference  
station.  
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Setting up the Receiver  
5
Mounting a pair of GPS receivers  
To obtain a position and heading solution, you need to connect two receivers to make  
one compact unit. A mounting bracket and interconnecting cable is supplied with the  
SPS551H receiver. Set up the receivers, antennas, and cables as shown in Figure 5.7.  
Dual-frequency rover antenna  
Dual-frequency rover antenna  
Antenna cable  
P/N 58957-05  
SPS551H  
Marine heading  
cable (P/N 57169-10)  
Serial Port 2  
SPS551H  
SPSx51  
Serial Port 2  
SPSx51  
Mounting bracket  
(P/N 56830-00)  
DC power  
Figure 5.7  
Installation setup for the SPS551H with another SPSx51 for position and heading  
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5
Setting up the Receiver  
Assembling the receivers  
Figure 5.8 shows an SPS551 and an SPS551H set up to provide a Heading solution. To  
assemble the receivers, you need a Phillips head #1 screwdriver and a 1/4" socket set or  
wrench (spanner).  
SPS551H GPS receiver  
SPS551 GPS receiver  
Figure 5.8  
Completed assembly with the SPS551H GPS receiver on top  
To assemble the receivers using the mounting frame that is provided:  
1. Invert the SPSx51 GPS receiver and then remove the rubber endcaps.  
2. Prepare the flat black plate and the four Posi screws. (These are part of the  
mounting frame.)  
3. Position the black plate on the SPSx51 GPS receiver.  
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Setting up the Receiver  
5
4. Use the four Posi screws to secure the plate to the receiver. (Secure two screws  
at each end.) The black plate is now attached to the bottom of the receiver.  
5. Replace the rubber endcaps.  
6. Invert the receiver again. This returns the receiver to its normal orientation.  
7. Set aside the receiver.  
8. Invert the SPS551H receiver and then remove the rubber endcaps.  
9. Position the black cradle on the SPS551H GPS receiver. (The black cradle is part  
of the mounting frame.)  
10. Use the four Posi screws to attach the black cradle to the receiver. The black  
cradle is now attached to the bottom of the SPS551H.  
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Setting up the Receiver  
11. Replace the rubber endcaps.  
12. Place the black cradle on the black base plate. This places the SPS551H GPS  
receiver on top of the SPSx51 GPS receiver.  
13. Make sure that the display is facing in the same direction on both receivers.  
14. Prepare the eight nuts, spring washers, and flat washers.  
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Setting up the Receiver  
5
15. Insert the first bolt. Attach the flat washer, the spring washer, and finally the nut  
and then tighten firmly. Secure all eight bolts in this way.  
16. Attach one connector from the Marine Heading cable (P/N 57169-10) to the  
26-pin connector on the rear of the SPS551H GPS receiver. Attach the other  
connector from the cable to the 26-pin connector on the rear of the SPSx51  
receiver. The cable can be connected either way around.  
The cable connects the two GPS receivers so that the Heading solution is  
available. The DC power lead on the cable supplies power to both receivers in  
the stack. The two DB9 female connectors on the cable access serial port 2 on  
each receiver.  
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Setting up the Receiver  
Installing the receiver  
Select a location at which all of the following conditions are met:  
the receiver is not exposed to temperature extremes  
the receiver is not exposed to moisture extremes (such as rain, snow, water  
blasters, or wash systems)  
the receiver is protected from mechanical damage  
you can connect and disconnect cables without placing undue stress on them  
Mounting the antennas  
You must install each antenna at the correct location. Poor or incorrect placement can  
influence accuracy and reliability.  
Ideally, mount the two antennas as far apart as possible and at about the same height  
on the structure. Mount the antennas fore and aft along the vessel centerline or on a  
line that is at a known orientation to the centerline. For best results, rotate each  
antenna so that all antennas in the array point in the same direction. Always mount an  
antenna at a location that ensures a good view of the sky.  
Follow these guidelines to select the antenna location:  
Choose an area with a clear view of the sky. The antenna must be above any  
metallic objects.  
Do not mount the antenna close to stays, electrical cables, metal masts, or other  
antennas.  
Do not mount the antenna near a transmitting antenna, a radar array, or near  
satellite communication equipment.  
Avoid areas with high vibration, excessive heat, electrical interference, and  
strong magnetic fields.  
Use a 5/8"×11" stainless steel bolt to mount each of the antennas. There is a threaded  
bolt hole in the base of the antenna.  
Configuring the receiver pair  
One of the receivers must be nominated as a Heading unit. The other receiver is  
nominated as a Moving Base unit. For this configuration to work, you must use the  
Marine Heading cable (P/N 57169-10).  
To set up the Heading unit:  
1. From the Home screen, press L twice. The Mode screen appears.  
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Setting up the Receiver  
5
2. Select Heading mode. The receiver display shows two extra settings for heading:  
Heading Adjustment. Enter a positive value in decimal degrees. The value is  
applied to the raw heading value before it is output in the NMEA HDT  
message or displayed on the front panel of the receiver. This value is used  
when the two antennas are not mounted parallel to the vessel axis.  
Minimum Heading Solution. Enter the minimum requirement for the GPS  
solution that will provide the heading value. The default of RTK Fixed  
provides the highest precision, but in conditions of extreme multipath or  
obstruction, an RTK Fixed solution may not be continuously available. In  
such conditions, select RTK Float if a lower precision is acceptable.  
To set up the Moving Base unit:  
1. From the Home screen, press L twice. The Mode screen appears.  
2. Select Moving Base mode, and then press L  
.
Interfacing using the NMEA protocol  
The SPS551H GPS receiver can output messages such as NMEA HDT for heading, and  
NMEA GGA for position. The SPS551H always reports the solution status of the  
moving baseline solution that is being used to compute the heading. However, if the  
external computer must know the exact quality of the position, you can use the NMEA  
output from the base receiver. The base receiver reports the solution status of the  
position, for example, Fixed Integer, Floating, or DGPS.  
Heading output  
The heading output from an SPSx51 receiver that is in Heading mode is the True North  
Azimuth from the Heading antenna (this is the unit that receives moving base  
corrections) to the Moving Base antenna (this is the unit that outputs the moving base  
corrections). Heading output information is available in the following places:  
Receiver display  
Data outputs:  
GSOF Attitude (see Attitude, page 146)  
NMEA HDT (see HDT, page 124)  
NMEA AVR (see PTNL,AVR, page 125)  
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5
Setting up the Receiver  
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C H A P T E R  
6
Configuring the Receiver Using the  
Keypad and Display  
6
In this chapter:  
The receiver features a keypad and display (see  
Keypad and display, page 24) so that you can  
configure the receiver without using a controller  
or computer.  
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6
Configuring the Receiver Using the Keypad and Display  
Button functions  
Use the buttons on the front panel to turn the receiver on and off and to check or  
change the receiver settings.  
Button Name  
Function  
Power  
Turns the receiver on and off. See the next section.  
E
Escape  
Returns to the previous screen or cancels changes being made on a  
screen.  
F
L
Enter  
Advances to the next screen or accepts changes made on a screen.  
Up  
Moves the cursor between multiple fields on a screen or makes changes  
to an editable field.  
J
Down  
Moves the cursor between multiple fields on a screen or makes changes  
to an editable field.  
K
I
G
Left  
Moves the cursor between characters in a field that can be changed.  
Right  
Moves the cursor between characters in a field that can be changed.  
Press this button to enter Edit mode.  
Power button operations  
Press the Power button  
to return to the Home screen, or hold down  
to turn the receiver on and off. In addition, you can tap  
E
E
to perform the following operations:  
E
To …  
Hold the  
button for …  
Notes  
E
turn off the receiver  
two seconds  
The display shows a countdown timer. When the display goes  
blank, release the Power button.  
clear the almanac,  
ephemeris, and SV  
information  
15 seconds  
The display show a countdown timer. When the display goes  
blank, continue to hold the Power button. The display shows a  
countdown time to clear the almanac and ephemeris. When  
the counter reaches 0, release the Power button.  
reset the receiver to its 35 seconds  
factory defaults and  
the default application  
file  
The display show a countdown timer. When the display goes  
blank, continue to hold the Power button. The display show a  
countdown to clear the almanac and ephemeris. When the  
counter reaches 0, continue to hold the Power button. The  
display indicates a countdown to resetting the receiver. When  
the counter reaches 0, release the Power button.  
force the receiver to  
power down  
at least 60  
seconds  
If the reset method above does not work, use this method to  
force the receiver to turn off. When the Power LED goes off,  
release the Power button.  
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Configuring the Receiver Using the Keypad and Display  
6
Home screen  
The Home screen is the main screen displayed on the receiver. If the receiver is  
displaying another screen and is left idle for 60 seconds, you are returned to the Home  
screen. It shows the following information:  
Number of satellites being tracked:  
When the receiver is in Base mode, the Home screen displays the number  
of satellites in view, that is, all satellites above the elevation mask. This is  
the number of satellites that the base station is sending data for.  
When the receiver is in Rover, Heading, or Moving Base mode, the Home  
screen displays the number of satellites used to calculate the position.  
If the receiver is set to use SBAS or OmniSTAR corrections, the Home  
screen displays the number of satellites that corrections have been received  
for.  
If the receiver is computing an autonomous solution, the Home screen  
displays all satellites in view, that is, all satellites above the elevation mask.  
Tip – You can also view these details using the Web browser (select Receiver Status /  
Position).  
B
Internal battery power remaining  
Current mode configuration  
Internal radio activity  
Internal radio channel or network  
Status screens  
The receiver has several view-only status screens that allow you to review the current  
settings of the receiver. The status screens provide the following information:  
Position solution and precisions  
CMR and RTCM IDs  
Base name and code  
Latitude, longitude, and height  
Antenna height  
Horizontal and vertical precision  
Receiver firmware version  
Receiver serial number  
Receiver IP address  
To access these screens from the Home screen, press J or K  
.
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6
Configuring the Receiver Using the Keypad and Display  
Configuring the receiver as a base receiver  
To set up the SPSx51 as a base receiver, use AutoBase technology, the Trimble SCS900  
Site Controller software, the receiver keypad, or an external computer.  
The AutoBase feature automatically configures the receiver settings for you. The  
receiver obtains a position and outputs RTK corrections on the internal radio (if  
available) or on the LEMO port. See Chapter 8, Automatically Setting up a Mobile Base  
The receiver is configured step-by-step to ensure that all appropriate settings are  
configured. To move between steps in the configuration process, press L .  
Configuring the receiver  
1. In the Home screen, press L . Use the Operation Mode screen to configure  
system settings, mode settings, or to view the SV (satellite) status. Mode Settings  
is the default setting.  
2. Press L . Use the Mode screen to select whether the receiver will operate as a  
base or rover. Base is the default setting.  
3. Press L . Use the Base Station screen to select whether the receiver is going to  
use a “Here” position or if the current coordinates in the receiver will be  
changed.  
4. Press G . When Edit Current begins to flash, the receiver is in Edit mode and  
you can change the current setting.  
5. Press K . The setting changes to New Base (Here).  
6. Press L to accept the change.  
7. Press L again. The Base Name screen appears. See next.  
Changing the name and description of the base station  
In the Base Name screen:  
1. Press G . When the first character of the base name begins to flash, the receiver  
is in Edit mode and you can change the current setting.  
2. Press J or K to change the value of the character.  
3. Press G to move the cursor to the next character.  
4. Repeat Step 2 through Step 3 to enter the name of the base station. The name  
can be up to 16 characters. Press L to accept the change.  
5. Press L again. Use the Base Code screen to change the code (description) for  
the base station.  
6. Press G . When the first character of the base code begins to flash, the receiver  
is in Edit mode and you can change the current setting.  
7. Press J or K to change the value of the character.  
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Configuring the Receiver Using the Keypad and Display  
6
8. Press G to move the cursor to the next character.  
9. Repeat Step 7 through Step 8 to enter the code of the base station. The code can  
be up to 16 characters.  
10. Press L to accept the change.  
11. Press L again. The Base Latitude screen appears. See next.  
Setting the reference latitude, longitude, and height of the base station  
In the Base Latitude screen:  
1. The base was set up with a “Here” position, so press  
.
L  
2. The Base Longitude screen is used to change the reference longitude of the base  
station. The base was set up with a “Here” position, so press  
.
L  
3. The Point Height screen is used to change the reference height of the base  
station. The base was set up with a “Here” position, so press  
.
L  
4. Use the Antenna Type screen to select the type of antenna used with the receiver.  
Press G . When the antenna name begins to flash, the receiver is in Edit mode  
and you can select an antenna.  
5. Press K to scroll through the antenna models.  
6. Once the correct antenna name appears, press L to accept the change.  
7. Press L again. The Measured To screen appears. See next.  
Measuring and changing the antenna height  
In the Measured To screen:  
1. Press G . When the antenna measurement method begins to flash, the receiver  
is in Edit mode and you can select an antenna measurement method.  
2. Press K to scroll through the measurement methods. Once the correct  
measurement method appears, press L to accept the change.  
3. Press L .  
4. Use the Antenna Height screen to change the height of the antenna. Press L .  
When the first character of the antenna height begins to flash, the receiver is in  
Edit mode and you can change the antenna height.  
5. Press J or K to change the value of the character.  
6. Press G to move the cursor to the next character.  
7. Repeat Step 5 through Step 6 to enter the height of the antenna.  
8. Press L to accept the change.  
9. Press L again. The Output screen appears. See next.  
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6
Configuring the Receiver Using the Keypad and Display  
Outputting corrections  
In the Output screen:  
1. Press G to enter Edit mode for the port.  
2. Press J or K to change which port will be used to output corrections.  
3. Press L to accept the change.  
4. Press K to move the cursor to the Format field.  
5. Press G to enter Edit mode for the format.  
6. Press J or K to change which correction message will be output on the port.  
7. Press L to accept the change.  
8. Press L again.  
9. Use the NMEA screen to set up NMEA outputs from the receiver. Press L to  
accept the default of no NMEA messages.  
10. Use the GSOF screen to set up GSOF outputs from the receiver. Press L to  
accept the default of no GSOF messages.  
11. Use the RT17 screen to set up RT17 outputs from the receiver. This screen only  
appears if you have the real-time Binary Output option installed. Press L to  
accept the default of no RT17 messages.  
The Home screen appears and the base setup is complete.  
Configuring the receiver as a rover receiver  
You can use the Trimble SCS900 Site Controller software or the receiver keypad to set  
up the SPSx51 as a rover receiver.  
The receiver is configured step-by-step to ensure that all appropriate settings are  
configured. To move between steps in the configuration process, press L .  
Configuring the receiver  
1. In the Home screen, press L . Use the Operation Mode screen to configure  
system settings, mode settings, or to view the SV (satellite) status. Mode Settings  
is the default setting.  
2. Press L . Use the Mode screen to select whether the receiver will operate as a  
base or rover.  
3. Press G . When the mode begins to flash, the receiver is in Edit mode and you  
can change this setting.  
4. Press K to change to Rover.  
5. Press L to accept the change.  
6. Press L again to move to the Elevation mask and RTK mode screen. See next.  
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Configuring the Receiver Using the Keypad and Display  
6
Changing the elevation mask and RTK mode  
1. Press G. When the value for the current elevation mask begins to flash, the  
receiver is in Edit mode and you can change the setting.  
2. Press K to change the elevation mask to the required value.  
Note – Trimble recommends that you do not set the elevation mask to a value lower than  
10 degrees.  
3. Press L to accept the change.  
4. Press K .  
5. In the Mode field, press G . When the current mode begins to flash, the receiver  
is in Edit mode and you can change this setting.  
6. Press K to change the desired RTK mode of the receiver.  
The Mode setting is either RTK Sync or Low Latency. RTK Sync waits for the  
corresponding base data to arrive. It provides positions slightly more accurate  
than the Low Latency mode, however it increases latency and has a maximum  
update rate of 1 Hz. Trimble recommends that you use the Low Latency mode.  
7. Press L to accept the change.  
8. Press L again. The Antenna Type screen appears. See next.  
Selecting the antenna  
In the Antenna Type screen:  
1. Press G . When the antenna name begins to flash, the receiver is in Edit mode  
and you can select the type of antenna that is to be used with the receiver.  
2. Press K to scroll through the antenna models.  
3. Once the correct antenna name appears, press L to accept the change.  
4. Press L again. The NMEA screen appears. See next.  
Outputting corrections  
In the NMEA screen, set up outputs from the receiver:  
1. Press L to accept the default of no NMEA messages.  
2. Use the GSOF screen to set up GSOF outputs from the receiver. Press L to  
accept the default of no GSOF messages.  
3. Use the RT17 screen to set up RT17 outputs from the receiver. Press L to  
accept the default of no RT17 messages. The Home screen appears, and the base  
setup is complete.  
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6
Configuring the Receiver Using the Keypad and Display  
Configuring system settings  
You can use the keypad and display of the receiver to configure the following settings:  
Display language  
Display and input units  
Baud rate, parity, data bits, and stop bits for serial ports  
Display power saver  
AutoBase warning  
Set position precisions  
To access the system settings:  
1. In the Home screen, press L . Use the Operation Mode screen to configure  
system settings or mode settings, and to view the SV (satellite) status. Mode  
Settings is the default setting.  
2. Press G . When the operation mode begins to flash, the receiver is in Edit mode  
and you can change this setting.  
3. Press K to change to System Setup.  
4. Press L to accept the change.  
5. Press L again.  
6. Use the Display Language screen, if necessary, to change the language. Choose  
English, Finnish, French, German, Italian, Spanish, or Swedish. Press L to  
accept the change.  
7. Press L again. Use the Display and Input Units screen, if necessary, to change  
the units to Meters or US Feet.  
8. Press L to accept the change.  
9. Press L again. Use the Port Settings screen, if necessary, to change the port.  
10. Press L to accept the change.  
11. Press L again. Use the Screen Pwr Savr screen to choose On, Off, or Auto. If you  
use the Auto setting, the screen turns off after 60 seconds of inactivity. The  
Power LED remains lit so that you can tell if the receiver is on or off. If an error  
message appears, the screen comes back on. Press L to accept the change and  
then press  
again to move to the next screen.  
L  
12. If you are using an SPSx51 RTK base station, the Autobase warning screen  
13. Press L to accept the change.  
14. Press L again. When the Home screen appears, the system setup is complete.  
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Configuring the Receiver Using the Keypad and Display  
6
Turning off AutoBase technology  
You can turn off AutoBase technology using either the receiver’s keypad and display or  
the web interface (see Receiver Configuration menu, page 90).  
When AutoBase technology is off, you can establish a new base station position in the  
receiver using the Edit Current or New Base (Here) menus. This does not automatically  
generate a new application file, but changes the settings in the current application file.  
When the receiver is turned on again, the most recent settings are always used.  
To turn off AutoBase technology using the receiver:  
1. In the Home screen, press L .  
2. Press G . When the operation mode begins to flash, the receiver is in Edit mode  
and you can change this setting.  
3. Press K to change to System Setup.  
4. Press L to accept the change.  
5. Press L again. You start to scroll through options in the System Setup menu.  
6. Keep pressing L until Autobase appears.  
7. Press G . The setting On flashes.  
8. Press K until it displays Off. Press L to accept the change.  
9. Press L again. The Active Appfile screen appears.  
Note – If AutoBase is turned on, the AutoBase Warning screen appears.  
To change the application file:  
Press G to display START Appfile.  
Press K to show SAVE Appfile.  
Press K to show DELETE Appfile.  
Press K to show START Appfile.  
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6
Configuring the Receiver Using the Keypad and Display  
Managing application files  
You can use the front panel to manage application files in the receiver. You can see  
which application file the receiver is currently using and then choose to make changes  
to it and save it, load a different application file, or delete an application file.  
To manage the application files, use the System Setup menu (see Figure 6.1). You can  
only manage application files when the AutoBase feature is turned off.  
To save an application file, configure all the settings you need through the front panel  
and then save the file. When you save the file, the receiver provides a default filename,  
which you can change, based on the currently set mode. For example:  
If the receiver is set to the following mode: The suggested application filename is:  
Base  
BASE01  
HDG01  
MB01  
Heading  
Moving Base  
Rover  
ROV01  
Note – If you start an application file that is saved with AutoBase turned on in the file,  
then it turns on AutoBase in the receiver, even if it was off before the file was loaded.  
No  
Yes  
Is AutoBase off?  
The following message  
Follow the usual  
AutoBase process.  
appears on the System  
Setup menu.  
Active Appfile  
No  
Yes  
<current app filename> *  
Do you want to do further  
Appfile handling?  
Press side arrow. START  
appfile will flash. Scroll  
through START, SAVE, DELETE.  
Press  
system setup.  
to complete  
L   
Press  
to make decision.  
L
Scroll through application  
files in the receiver. Make  
decision by pressing  
.
L
Display shows the active  
application file. Press  
to complete.  
L
Note – The '*' after the <current app filename> signifies it is the application file currently in use by the receiver.  
Figure 6.1  
Application file handling through the front panel of the receiver  
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C H A P T E R  
7
Configuring the Receiver Settings  
7
In this chapter:  
You can configure the SPS GPS receiver family in  
a variety of ways. This chapter describes the  
different configuration methods, and explains  
when and why each method is used.  
The SCS900 Site Controller software is likely to be  
your main tool to set up and operate the receiver  
on a daily basis. All necessary field configurations  
are handled through the SCS900 software  
running on a TSC2 or Trimble CU controller. For  
more information, refer to the Trimble SCS900  
Site Controller Software Office Guide.  
The external software detailed in this chapter is  
primarily used to update the receiver firmware  
and to configure upgrades or radio channels.  
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7
Configuring the Receiver Settings  
Using the SCS900 Site Controller software to configure the  
base station, the rover, and the radios  
As part of a total system solution for construction applications, the SPS GPS receivers  
are operated by a TSCe, ACU, TCU, or TSC2 controller running the SCS900 Site  
Controller software. The SCS900 Site Controller software provides the tools to  
configure and start the GPS receiver in the modes used by the SCS900 system: RTK  
Base Station, RTK Rover, DGPS Rover, OmniSTAR rover, SBAS Rover (using  
WAAS/EGNOS/MSAS). Wizards help you through the process and, where possible,  
assign suitable default operational parameters to the system. This eliminates the need  
for an operator to know how to configure the receiver with the right settings.  
The SCS900 Site Controller software manages:  
the radio, whether internal or external  
all cellular communications components, such as modems and cell phones  
the use of the Bluetooth wireless technology  
The software also scans communication ports on the receiver to identify connected  
devices. If the software cannot automatically identify the connected component, for  
example, a GPS antenna, it offers options (often with graphics) to help you manually  
select the correct component.  
The SCS900 Site Controller software allows you to set operational tolerances and  
settings (such as those shown below), which must be achieved before measurements  
can be accepted. When outside of these tolerances, the SCS900 Site Controller  
software warns you through on-screen messages or indications, and the  
non-automatic acceptance of recorded positions. To set operational tolerances, go to  
the Settings menu in the SCS900 Site Controller software.  
Example 1: From the Sky Plot screen, press  
Ctrl+M to open this screen and change the angle  
below which the receiver will not track satellites  
Example 2: Use the Sky Plot screen to  
set if the receiver will track GLONASS satellites  
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Configuring the Receiver Settings  
7
Configuring the receiver to log data for postprocessing  
The receivers do not come equipped with the Data Logging option. The receivers can  
have this added either at the time of purchase, or at a later date as an option. With the  
Data Logging option enabled, the receiver has available memory that facilitates the  
collection of GPS observations over a period of time, and that can be used with GPS  
postprocessing software such as the Trimble Geomatics Officefor the computation  
of control networks and baselines.  
Note – Version 2.30 and later of the SCS900 software supports the recording of raw GPS  
data in the SPS receivers when the Data Logging option is installed in the receiver. For  
information on how to initiate recording in the SPS receivers from SCS900, refer to the  
SCS900 Precision GPS User Guide.  
Configuring the receiver to use specific settings when it is  
turned on  
The power up application file (Power_up.cfg) is used to set the receiver to a specific  
configuration any time the unit is powered up.  
In this file, you can specify that the receiver is reset to defaults before the power up  
settings are applied. This ensures that restarting the receiver always resets it to factory  
defaults prior to applying the power up application file.  
Alternatively, you can specify that the power up settings are applied immediately after  
the current application file’s settings have been applied. Restarting the receiver results  
in a configuration that uses your default settings for the options you define in the  
power up file, but the current settings for all other options.  
By default, there is no power_up application file on the receiver. To use a power up  
application file, you must create and save a power_up application file in the GPS  
Configurator software. If you save this file to disk, the file is called power_up.cfg. The  
extension .cfg is used, by convention, to identify application files on the office  
computer. When you transfer this file to the receiver, the file is saved on the receiver as  
power_up, and becomes the new power up file.  
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7
Configuring the Receiver Settings  
Configuring Ethernet settings  
The receiver has an Ethernet port so that the receiver can connect to an Ethernet  
network. You can use the Ethernet network to access, configure, and monitor the  
receiver. No serial cable connection to the receiver is necessary.  
The receiver requires the following Ethernet settings:  
IP setup: Static or DHCP  
IP address  
Netmask  
Broadcast  
Gateway  
DNS address  
HTTP port  
The default setting for the HTTP port is 80. The HTTP port is not assigned by the  
network. HTTP port 80 is the standard port for web servers. This allows you to connect  
to the receiver by entering only the IP address of the receiver in a web browser. If the  
receiver is set up to use a port other than 80, you will need to enter the IP address  
followed by the port number in a web browser.  
Example of connecting to the receiver using port 80: http://169.254.1.0  
Example of connecting to the receiver using port 4000: http://169.254.1.0:4000  
The default setting of the receiver is to use DHCP. Using DHCP enables the receiver to  
automatically obtain the IP address, Netmask, Broadcast, Gateway, and DNS address  
from the network.  
When a receiver is connected to a network  
using DHCP, the network assigns an IP address  
to the receiver. To verify the IP address, select  
the up button from the keypad when the Home  
screen is displayed. The Ethernet IP address  
appears. The screen shown is of a receiver that has failed to get an IP address.  
If your network installation requires the receiver to be configured with a static IP  
address, you can configure the Ethernet settings using the web server or the WinFlash  
utility. The web server can be used only when the receiver is connected to a network  
and has a valid Ethernet configuration. When DHCP fails, the receiver uses a private IP.  
Use the WinFlash utility to configure the Ethernet settings of a receiver that is to be  
connected to a network that requires static IP addresses:  
1. Contact the network administrator for the correct settings for the receiver.  
2. Connect the receiver to a computer running the WinFlash utility using the serial  
cable provided with the receiver.  
3. Turn on the receiver.  
4. On the computer, start the WinFlash utility.  
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Configuring the Receiver Settings  
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5. From the Device Configuration screen, select the Trimble SPSx51 Receiver. From  
the PC serial port list, select the appropriate PC serial port. Click Next:  
6. From the Operation Selection screen, select Configure ethernet settings, and then  
click Next:  
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Configuring the Receiver Settings  
7. From the Settings Review screen, click Finish:  
Once the WinFlash utility connects to the receiver, the Ethernet Configuration  
dialog appears.  
8. Enter the network settings in the Ethernet Configuration dialog. Click OK:  
The Broadcast setting is the IP address that is used to broadcast to all devices on  
the subnet. This is usually the highest address (usually 255) in the subnet.  
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Configuring the receiver using a web browser  
The receiver can be configured using the keypad and display, Trimble SCS900 Site  
Controller software, or a web browser. This section describes how to set up the receiver  
using a web browser.  
Supported browsers  
Mozilla Firefox version 1.07 or later (version 1.50 or later is recommended for  
Windows, Macintosh, and Linux operating systems)  
Microsoft Internet Explorer® version 6.00 or later for Windows operating  
systems  
Connecting to the receiver using a web browser:  
1. Enter the IP address of your receiver into the address bar of the web browser as  
shown:  
2. If security is enabled on the receiver, the web browser prompts you to enter a  
username and password:  
The default login values for the receiver are:  
User Name: admin  
Password: password  
If you cannot connect to the receiver, the password for the admin account may  
have been changed, or a different account may be in use. Contact your receiver  
administrator for the appropriate login information.  
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7
Configuring the Receiver Settings  
Connecting to the receiver using a web browser and Bluetooth wireless  
technology  
This section describes how to access the web interface on a SPSx51 Modular GPS  
receiver that has firmware version 3.32 or later installed, using Bluetooth wireless  
technology on an office computer that has Service Pack 2 of the Windows XP  
operating system (Professional Edition) installed.  
1. On the office computer, open the Control Panel. Open Bluetooth Configuration  
and go to the Client Applications tab. The following dialog appears:  
2. Add at least one Bluetooth Serial port. To do this, click Add COM port and then  
follow the steps through the wizard. Name the COM port appropriately and  
clear the Secure Connection check box.  
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Configuring the Receiver Settings  
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3. Start the Bluetooth Setup wizard (click Start / All Programs / My Bluetooth Places):  
4. The Bluetooth Setup wizard starts. Use the settings shown below and then click  
Next:  
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Configuring the Receiver Settings  
The following dialog appears:  
5. Select the Bluetooth serial port you created and then click Next. The following  
dialog appears:  
6. In the Search criteria list, change the search to Show all devices and then select  
the modular GPS receiver that you want to connect to. Click Next.  
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The following dialog appears:  
7. Click Configure to select the COM port on your office computer. Think of  
Bluetooth as a cable replacement and this as the serial port on your office  
computer into which the Bluetooth ‘cable’ will be connected. The following  
dialog appears:  
8. Ensure that the Secure Connection check box is cleared and then tap OK.  
9. Tap Finish. The new Bluetooth connection appears in My Bluetooth places.  
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Configuring the Receiver Settings  
10. Double-click this icon to connect:  
Creating a new connection  
1. From your Windows Control Panel, open Network Connections and then click  
Create a new connection:  
2. The New Connection wizard starts. Complete the wizard using the following  
settings:  
Set up an advanced connection  
Connect directly to another computer  
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Configuring the Receiver Settings  
7
Guest  
3. Give the connection a name which relates to the COM port being used on the  
office computer. This is like a cable connection between two computers only the  
cable is being replaced by a Bluetooth wireless connection. Tap Next. The  
following dialog appears:  
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Configuring the Receiver Settings  
4. Select the correct COM port from the list and then tap Next. The following  
dialog appears:  
5. Enter the user name and password and then click Connect.  
The defaults for the SPSx51 receiver are:  
Username: admin  
Password: password  
6. The new Direct connection appears in the Network Connections folder. If that  
status shows as Connected, you can continue to the web interface.  
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7. Right-click on the connection and select Status:  
8. The Details tab shows the Server IP address. Use this IP to connect to the  
receiving using the web interface.  
Tip – You can also get the PPP address from the front panel of the receiver by pressing  
from the Home screen.  
J
B
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Configuring the Receiver Settings  
Menus  
Once you are logged in, the home page appears (see Figure 7.1).  
Serial number of receiver  
Model name of receiver  
Available  
languages  
Menus  
Figure 7.1  
SPS GPS receiver Home page  
Changing the settings  
Use the webpage to configure the receiver settings. The web interface shows the  
configuration menus on the left of the browser window, and the settings on the right.  
Each configuration menu contains related submenus to configure the receiver and  
monitor receiver performance.  
Note – The configuration menus available vary based on the version of the receiver.  
A summary of each configuration menu is provided here. For more detailed  
information about each of the receiver settings, select the Help menu. The Help is  
available whenever your computer is connected to the Internet. It is also available  
anytime from the Trimble website (www.trimble.com/EC_ReceiverHelp/v3.60/en).  
To display the web interface in another language, click the corresponding country flag.  
The web interface is available in the following languages:  
English (en)  
Chinese (zh)  
Finnish ( fi)  
French (fr)  
German (de)  
Italian (it)  
Japanese (ja)  
Russian (ru)  
Spanish (es)  
Swedish (sv)  
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Receiver Status menu  
The Receiver Status menu provides a quick link to review the receiver’s available  
options, current firmware version, IP address, temperature, runtime, satellites tracked,  
current outputs, available memory, position information, and more.  
This figure shows an example of the screen that appears when you select Receiver  
Status / Identity.  
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Configuring the Receiver Settings  
Satellites menu  
Use the Satellites menu to view satellite tracking details and enable/disable GPS,  
GLONASS, and SBAS (WAAS/EGNOS and MSAS) satellites.  
Note – To configure the receiver for OmniSTAR, use the OmniSTAR menu. See page 94.  
This figure shows an example of the screen that appears when you select Satellite /  
Tracking (Sky Plot).  
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Data Logging menu  
Use the Data Logging menu to set up the receiver to log static GPS data. This menu is  
available only if the receiver has the Data Logging option enabled. You can also  
configure settings such as observable rate, position rate, continuous logging,  
continuous logging rate, and whether to auto delete old files if memory is low.  
This figure shows an example of the screen that appears when you select Data Logging  
/ Configuration.  
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Configuring the Receiver Settings  
Receiver Configuration menu  
Use the Receiver Configuration menu to configure such settings as elevation mask and  
PDOP mask, the antenna type and height, the reference station position, and the  
reference station name and code.  
This figure shows an example of the screen that appears when you select Receiver  
Configuration / Summary.  
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Configuring the Receiver Settings  
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I/O Configuration menu  
Use the I/O Configuration menu to set up all outputs of the receiver. The receiver can  
output CMR, RTCM, NMEA, GSOF, or BINEX messages. These messages can be output  
on TCP/IP, UDP, serial, Bluetooth, or radio ports.  
This figure shows an example of the screen that appears when you select  
I/O Configuration / Port Summary.  
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Configuring the Receiver Settings  
Bluetooth menu  
Use the Bluetooth menu to configure the receiver to connect to other devices that use  
Bluetooth wireless technology. These devices can be used to configure the receiver, and  
generate or receive corrections. The following Trimble devices can be connected to an  
SPSx51 receiver using Bluetooth wireless technology:  
TSC2 controller  
TCU controller  
TSCe controller  
ACU controller  
SNB900 radio-modem  
Other Bluetooth-enabled SPS GPS receivers  
This figure shows an example of the screen that appears when you select Bluetooth /  
Info.  
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Radio menu  
Use the Radio menu to configure the internal radio of the receiver, if applicable. The  
receivers are available with 410–430 MHz, 430–450 MHz, 450–470 MHz, or 900 MHz  
radios. The SPS551H receiver does not have an internal radio.  
This figure shows an example of the screen that appears when you select Radio.  
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Configuring the Receiver Settings  
OmniSTAR menu  
All receivers, except the SPS551H, can receive OmniSTAR corrections. By default,  
OmniSTAR tracking is turned on in the receiver. To receive OmniSTAR corrections, you  
must set the receiver to track OmniSTAR satellites and it must have a valid OmniSTAR  
subscription. To purchase a subscription for your receiver, contact OmniSTAR at:  
North & South America, 1-888-883-8476 or 1-713-785-5850  
Europe & Northern Africa, 31-70-317-0900  
Australia & Asia, 61-8-9322 5295  
Southern Africa, 27 21 552 0535  
This figure shows an example of the screen that appears when you select OmniSTAR /  
Summary.  
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Configuring the Receiver Settings  
7
Network Configuration menu  
Use the Network Configuration menu to configure Ethernet settings, email alerts, PPP  
connection, HTTP port, FTP port, and VFD port settings of the receiver. For  
information on the Ethernet settings, see Configuring Ethernet settings, page 74.  
The VFD port allows you to use the SPSx51 Remote Control application to view and  
navigate the receiver through a mock display and keypad interface. To allow the  
SPSx51 Remote Control to connect to the receiver, you need to enable the VFD port. To  
do this, select Network Configuration / VFD.  
This figure shows an example of the screen that appears when you select Network  
Configuration / Ethernet.  
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Configuring the Receiver Settings  
Security menu  
Use the Security menu to configure the login accounts for all users who will be  
permitted to configure the receiver using a web browser. Each account consists of a  
username, password, and permissions. Administrators can use this feature to limit  
access to other users. Security can be disabled for a receiver. However, Trimble  
discourages this as it makes the receiver susceptible to unauthorized configuration  
changes.  
This figure shows an example of the screen that appears when you select Security /  
Configuration.  
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Configuring the Receiver Settings  
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Firmware menu  
Use the Firmware menu to verify the current firmware and load new firmware to the  
receiver. You can upgrade firmware across a network or from a remote location  
without having to connect to the receiver with a serial cable.  
This figure shows an example of the screen that appears when you select Firmware.  
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Configuring the Receiver Settings  
Help Menu  
The Help menu provides information on each of the receiver settings available in a web  
(www.trimble.com/EC_ReceiverHelp/v3.60/en (For languages other than English,  
replace en with the appropriate two-letter country code (see page 86)) and are updated  
between firmware releases.  
To access the Help, your computer must be connected to the Internet. If you do not  
have access to the Internet, there is also a copy of the receiver Help files on the Trimble  
SPS GPS Receiver CD. (This copy shows the Help files as they were when the CD was  
published.)  
This figure shows an example of the screen that appears when you select Help.  
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C H A P T E R  
8
Automatically Setting up a Mobile Base  
Station Using AutoBase Technology  
8
In this chapter:  
The AutoBase technology is a feature of the  
Trimble receivers that enables you to reduce  
daily setup time for mobile base stations and to  
reduce the likelihood of using incorrect base  
station coordinates during setup.  
The AutoBase feature allows you to set up a  
receiver as a base station receiver and save you  
time so you do not need to reconfigure the  
receiver at the start of each day. It also allows you  
to set up the base station on a new site without  
needing to configure the settings in the receiver.  
Even if you have used the AutoBase  
feature in other Trimble receivers, Trimble  
recommends that you read this chapter carefully  
because new functions in this feature provide  
greater benefit to you.  
Note – For information about turning AutoBase off  
using the receiver, see Chapter 6, Configuring the  
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Automatically Setting up a Mobile Base Station Using AutoBase Technology  
AutoBase Warning  
The AutoBase Warning, when enabled, prevents the receiver from creating a new base  
station position and begin operating as an RTK base station when no previous base  
station position exists that corresponds to the current position of the receiver.  
When the AutoBase Warning is on, the receiver will not begin transmitting RTK  
corrections from a base position (latitude, longitude, and height) that is not a part of  
the GPS site calibration. When the AutoBase Warning is off, the receiver begins  
transmitting RTK corrections from a new base position. You need only turn on the  
receiver the first time on a point, and you do not need to manually configure the base  
station settings.  
By default, the receivers have the AutoBase Warning turned on. The receiver uses the  
AutoBase Warning setting to control how the receiver performs when different criteria  
are met. You can turn the AutoBase Warning on or off using the keypad and display. For  
Working with AutoBase technology  
This section contains some example scenarios. In each section, there is a step-by-step  
process that explains what you will experience in each scenerio.  
Scenario One: First visit to a site with AutoBase Warning turned off  
The following actions occur when you set up the base station for the first time on a  
new point and the AutoBase Warning is turned off:  
1. The receiver is powered on.  
2. The receiver begins tracking satellites.  
3. The receiver determines the current position.  
4. The receiver reviews the previous base station positions stored in the receiver.  
5. The receiver does not find any base station that corresponds to the current  
position.  
6. The receiver creates a new base station location for the current location.  
7. The receiver sets the antenna height to 0. The antenna height is measured to the  
bottom of the antenna mounting.  
CAUTION – On each reoccupation of the point, you must ensure that the receiver  
antenna is set up in exactly the same location and at exactly the same height. Trimble also  
recommends that you use a T-bar or Fixed height tripod so that the position is easy to  
re-establish. Failure to achieve the same height position for the antenna results in errors  
in heights in subsequent measurements.  
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Where you set up each time with potentially different antenna heights, Trimble  
recommends that on the first setup after AutoBase has completed its process,  
that you edit the antenna height (using the receiver keypad and display). The  
updated antenna height changes the AutoBase setup, so that on subsequent  
setups, when you again change the antenna height, you will get correct height  
information during measurement. At the first setup, Trimble recommends that  
you change the AutoBase setup and antenna height before you carry out a site  
calibration.  
8. The receiver begins generating RTK CMR+ corrections.  
9. The RTK corrections begin streaming over the internal radio. If there is no  
internal radio, the receiver defaults to streaming the corrections on the Lemo  
port.  
Scenario Two: First visit to a site with AutoBase Warning turned on  
The following actions occur when you set up the base station for the first time on a  
point, and the AutoBase Warning is turned on:  
1. The receiver is powered on.  
2. The receiver begins tracking satellites.  
3. The receiver determines the current position.  
4. The receiver reviews the base positions stored in the receiver.  
5. The receiver does not find any base station that corresponds to the current  
position.  
6. The receiver displays a warning that AutoBase has failed.  
7. No RTK corrections are streamed until the base station is set up using the  
keypad and display or an SCS900 controller.  
Scenario Three: Repeat visit to a site with AutoBase Warning turned off  
The following actions occur when you repeat a base station setup on a point, and the  
AutoBase Warning is turned off:  
1. The receiver is powered on.  
2. The receiver begins tracking satellites.  
3. The receiver determines the current position.  
4. The receiver reviews the base station positions stored in the receiver.  
5. The receiver finds a base station position that corresponds to the current  
position.  
CAUTION – If there are two or more base positions within a 50 meter radius of your  
current position, the receiver will make the most recently used base position file active.  
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Automatically Setting up a Mobile Base Station Using AutoBase Technology  
6. The antenna type, antenna height and measurement method used in the  
previous setup of this base station are applied.  
CAUTION – If the antenna height is different to the previous setup, then you must enter  
the corrected height for the antenna (using the keypad and display) before starting  
measurements. Failure to achieve the correct antenna height position for the antenna  
results in errors in heights in subsequent measurements.  
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7. The receiver begins sending RTK CMR+ messages.  
8. The RTK corrections begin streaming on the radio or Lemo port in the  
application file.  
Scenario Four: Repeat visit to a site with AutoBase Warning turned on  
The following actions occur when you repeat a base station setup on a point, and the  
AutoBase Warning is turned on:  
1. The receiver is powered on.  
2. The receiver begins tracking satellites.  
3. The receiver determines the current position.  
4. The receiver reviews the base station positions stored in the receiver.  
5. The receiver finds a base station position that corresponds to the current  
position.  
CAUTION – If there are two or more base positions within a 50 meter radius of your  
current position, the receiver will make the most recently created base position file active.  
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6. Since a base station position is found, the AutoBase warning does not appear.  
7. The receiver loads the previous base information.  
8. The antenna type, antenna height, and measurement method used in the  
previous setup of this base station are applied.  
CAUTION – If the antenna height is different from the previous setup, then you must  
enter the corrected height for the antenna (using the keypad and display) before starting  
measurements. Failure to achieve the correct antenna height position for the antenna  
results in errors in heights in subsequent measurements.  
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9. The receiver begins generating RTK CMR+ corrections.  
10. The RTK corrections begin streaming on the radio or port defined in the  
previous setup of this base station.  
Note – AutoBase recalls base station positions that are stored in the receiver. If the receiver  
has been previously set up on a control point but the stored base station position is not  
found in the receiver, it is possible that the information may have accidently been deleted.  
In this case, use the display and keypad or the SCS900 system to manually set up the base  
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Automatically Setting up a Mobile Base Station Using AutoBase Technology  
8
station. Make sure that you use the same base station latitude, longitude, and height as in  
the previous setup otherwise you will experience position or height errors in all subsequent  
measurements.  
Trimble recommends that after any new base station setup, or at the start of each  
measurement session, you measure a known point to verify that position and height errors  
are within tolerance. This is good practice and it takes just a few seconds to eliminate  
potentially gross errors typically associated with repeated daily base station setups.  
The AutoBase process  
Power On  
Receiver  
Auto Base  
turned on  
Auto Base  
turned off  
Receiver  
looks for  
application  
files  
Status last  
application  
file used  
before  
Do  
application  
files exist?  
power off.  
No  
Yes  
Is  
AutoBase  
Warning  
On or Off?  
Any  
application  
file that  
corresponds  
with the  
current  
position?  
On  
Off  
Display  
AutoBase  
Warning  
No  
Yes  
Create new  
application  
file  
Is there more  
than one  
acceptable  
application  
file?  
Save new  
application  
file with  
“Auto” base  
name  
Yes  
No  
Make most  
recently  
created  
application  
active  
Make  
Make new  
“Auto”  
application  
file active  
corresponding  
application  
file active  
Figure 8.1  
Autobase process flowchart  
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Automatically Setting up a Mobile Base Station Using AutoBase Technology  
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C H A P T E R  
9
Default Settings  
9
In this chapter:  
All settings are stored in application files. The  
default application file, Default.cfg, is stored  
permanently in the receiver, and contains the  
factory default settings. Whenever the receiver is  
reset to its factory defaults, the current settings  
(stored in the current application file,  
Current.cfg) are reset to the values in the default  
application file.  
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Default Settings  
Default receiver settings  
These settings are defined in the default application file.  
Function  
Factory default  
All SVs enabled  
10°  
SV Enable  
General Controls:  
Elevation mask  
PDOP mask  
RTK positioning mode  
Motion  
7
Low Latency  
Kinematic  
38,400  
Lemo Port:  
Baud rate  
Format  
8-None-1  
None  
Flow control  
Baud rate  
Modem Port:  
38,400  
Format  
8-None-1  
None  
Flow control  
Station  
Input Setup:  
Any  
NMEA/ASCII (all supported messages)  
Streamed output  
All ports Off  
All types Off  
Offset = 00  
RT17/Binary  
All ports Off  
Reference position: Latitude  
Longitude  
0°  
0°  
Altitude  
0.00 m HAE (Height above ellipsoid)  
Zephyr Geodetic Model 2  
0.00 m  
Antenna:  
Type  
Height (true vertical)  
Measurement method  
Bottom of antenna mount  
Resetting the receiver to factory defaults  
To reset the receiver to its factory defaults, press E for 35 seconds.  
Data Logging option  
By default, the Data Logging option is turned off in SPS GPS receivers. If you choose to  
log data using a GPS receiver, you must enable the option and acquire suitable GPS  
postprocessing software, such as the Trimble Geomatics Office software. For more  
information, please contact your Trimble dealer.  
Postprocessed GPS data is typically used for control network measurement  
applications and precise monitoring. GPS measurement data is collected over a period  
of time at a static point or points and then postprocessed to accurately compute  
baseline information.  
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Default Settings  
9
Logging data after a power loss  
If power is unexpectedly lost while the receiver is logging data, once power is restored,  
the receiver tries to return to the state it was in immediately before the power loss. The  
receiver does not reset itself to default settings.  
If the receiver was logging data when power was lost, data logging is resumed when  
power is provided.  
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9
Default Settings  
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C H A P T E R  
10  
Specifications  
10  
In this chapter:  
This chapter details the specifications for the  
receiver.  
Specifications are subject to change without  
notice.  
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10 Specifications  
General specifications  
Feature  
Specification  
Keyboard and display  
VFD display 16 characters by 2 rows  
On/Off key for one button startup using AutoBase technology  
Escape and Enter key for menu navigation  
4 arrow keys (up, down, left, right) for option scrolls and data entry  
Modular GPS receiver  
Receiver type  
Antenna type  
L1/L2/L2C GPS  
operations  
Zephyr Model 2, GA510  
GLONASS operations  
Base station  
Zephyr Model 2  
Zephyr Geodetic Model 2  
GA510, Zephyr Model 2  
OmniSTAR operations  
Also supports legacy Trimble antennas Z+ Choke ring, Zephyr, Zephyr Geodetic,  
Micro-Centered  
.
Physical specifications  
Feature  
Specification  
Dimensions (L x W x H)  
Weight  
24 cm (9.4 in) x 12 cm (4.7 in) x 5 cm (1.9 in) including connectors  
1.65 kg (3.64 lbs) receiver with internal battery and radio  
1.55 kg (3.42 lbs) receiver with internal battery and no radio  
1
Temperature  
Operating  
Storage  
–40 °C to +65 °C (–40 °F to +149 °F)  
–40 °C to +80 °C (–40 °F to +176 °F)  
Humidity  
MIL-STD 810F, Method 507.4  
Waterproof  
IP67 for submersion to depth of 1 m (3.30 ft)  
Tested and meets the following environmental standards:  
Shock and vibration  
Shock, non operating  
Designed to survive a 1 m (3.3 ft) pole drop onto a hard surface  
to 75 g, 6 ms  
Shock, operating  
Vibration  
To 40 g, 10 ms, saw-tooth  
Tested to Trimble ATV profile (4.5 g  
):  
RMS  
2
10 Hz – 300 Hz: 0.04 g /Hz  
300 Hz – 1,000 Hz; -6 dB/octave  
1 Receiver will operate normally to –40 °C. Internal batteries are rated to –20 °C.  
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Specifications 10  
Performance specifications  
Feature  
Specification  
Measurements  
Advanced Trimble Maxwell 5 Custom GPS chip  
High-precision multiple correlator for L1/L2 pseudo-range measurements  
Unfiltered, unsmoothed pseudo-range measurements for low-noise, low  
multipath error, low-time domain correclation, and high-dynamic response  
Very low noise carrier phase measurements with <1 mm precision in a 1 Hz  
bandwidth  
L1/L2 signal-to-noise ratios reported in dB-Hz  
Proven Trimble low-elevation tracking technology  
Trimble EVEREST multipath signal rejection  
72-channel L1 C/A Code, L1/L2 Full Cycle Carrier. Upgradable to L2C and  
GLONASS L1/L2 Full Cycle Carrier. See page 114.  
72-channel L1 C/A Code, L1/L2/L2C Full Cycle Carrier (SPS751/SPS851).  
Upgradable to GLONASS L1/L2 Full Cycle Carrier and L5. See page 114.  
(SPS851)  
4-channel SBAS (WAAS, EGNOS, and MSAS corrections)  
Code differential GPS  
1
positioning  
Horizontal accuracy  
Vertical accuracy  
(0.25 m + 1 ppm) RMS, (0.8 ft + 1 ppm) RMS  
(0.50 m + 1 ppm) RMS, (1.6 ft + 1 ppm) RMS  
SBAS (WAAS/EGNOS/MSAS)  
2
Horizontal accuracy  
Typically <1 m (3.3 ft)  
Typically <5 m (16.4 ft)  
2
Vertical accuracy  
OmniSTAR positioning  
VBS service accuracy  
XP service accuracy  
HP service accuracy  
Location RTK positioning  
Horizontal accuracy  
Vertical accuracy  
Horizontal <1 m (3.3 ft)  
Horizontal 0.2 m (0.66 ft), Vertical 0.3 m (1.0 ft)  
Horizontal 0.1 m (0.33 ft), Vertical 0.15 m (0.5 ft)  
(0.07 m + 1 ppm) RMS, (0.23 ft +1 ppm) RMS  
(0.07 m + 1 ppm) RMS, (0.23 ft +1 ppm) RMS (SPS551)  
(0.02 m + 1 ppm) RMS, (0.07 ft +1 ppm) RMS (SPS651)  
RTK positioning  
Horizontal accuracy  
Vertical accuracy  
(10 mm + 1 ppm) RMS, (0.032 ft +1 ppm) RMS (SPS751/SPS851)  
(20 mm + 1 ppm) RMS, (0.065 ft +1 ppm) RMS (SPS751/SPS851)  
0.05° RMS (10 m antenna separation)  
Heading accuracy with  
additional SPS551, SPS551H,  
SPS751, or SPS851  
Does not require shore-based corrections for heading solution  
Initialization time  
Regular RTK operation Single/Multi-base minimum 10 sec + 0.5 times baseline length in km, <30 km  
with base station  
RTK operation with  
Scalable GPS  
Typically, <30 seconds anywhere within coverage area (SPS751 Max and SPS851  
only).  
infrastructure  
3
Initialization reliability  
Typically >99.9%  
1 Accuracy and reliability may be subject to anomalies such as multipath, obstructions, satellite geometry, and  
atmospheric conditions. Always follow recommended practices.  
2 Depends on WAAS, EGNOS, and MSAS system performance.  
3 May be affected by atmospheric conditions, signal multipath, and satellite geometry. Initialization reliability is  
continuously monitored to ensure highest quality.  
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10 Specifications  
Electrical specifications  
Feature  
Specification  
Power  
Internal  
Integrated internal battery 7.4 V, 7800 mA-hr, Lithium-ion  
Internal battery operates as a UPS in the event of external power source  
failure  
Internal battery will charge from external power source when input  
voltage is >15 V  
Integrated charging circuitry  
Power input on Lemo 7-pin 0-shell is optimized for lead acid batteries with  
a cut-off threshold of 10.5 V  
External  
Power input on the 26-pin D-sub connector is optimized for Trimble  
Lithium-ion battery input (P/N 49400) with a cut-off threshold of 9.5 V  
Power source supply (Internal/External) is hot-swap capable in the event of  
power source removal or cut off  
9.5 V to 28 V DC external power input with over-voltage protection  
Receiver will automatically turn on when connected to external power  
6 W, in rover mode with internal receive radio  
Power consumption  
8 W in base mode with internal transmit radio  
Base station operation times on  
internal battery  
External radio  
14 hours; varies with temperature  
10 hours; varies with temperature  
9 hours; varies with temperature  
1
450 MHz 0.5 W systems  
900 MHz 1.0 W systems  
Rover operation time on  
internal battery  
450 MHz 2.0 W systems  
900 MHz 1.0 W systems  
Regulatory approvals  
12 hours; varies with temperature  
12 hours; varies with temperature  
FCC: Part 15 Subpart B (Class B Device) and Subpart C, Part 90  
Industry Canada: ICES-003 (Class B Device), RSS-210, RSS-Gen, RSS-310,  
RSS-119  
R&TTE Directive: EN 301 489-1/-5/-17, EN 300 440, EN 300 328, EN 300 113,  
EN 60950, EN 50371  
ACMA: AS/NZS 4295 approval  
CE mark compliance  
C-tick mark compliance  
UN ST/SG/AC.10.11/Rev. 3, Amend. 1 (Li-Ion Battery)  
UN ST/SG/AC. 10/27/Add. 2 (Li-Ion Battery)  
RoHS compliant (excludes receivers with an internal 900 MHz radio)  
WEEE compliant  
1If your receiver has the 2.0 W upgrade, you will experience lesser battery performance compared to the 0.5 W  
solution.  
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Specifications 10  
Communication specifications  
Feature  
Specification  
Communications  
Port 1 (7-pin 0S Lemo)  
Port 2 (26-pin D-sub)  
3-wire RS-232/CAN  
Full RS-232 (through multi-port adaptor)  
3-wire RS-232  
1PPS (1 Pulse per second)  
USB (On the Go)  
Through adaptor cable  
Through mutli-port adaptor  
Through mutli-port adaptor  
Ethernet  
1
Bluetooth  
Fully-integrated, fully-sealed 2.4 GHz Bluetooth module  
Integrated radios (optional)  
Fully-integrated, fully-sealed internal 450 MHz (UHF), Tx, Rx,  
or Tx/Rx  
Fully-integrated, fully-sealed internal 900 MHz, Tx, Rx, or  
Tx/Rx  
Channel spacing (450 MHz)  
12.5 KHz or 25 KHz spacing available  
450 MHz transmitter radio power output 0.5 W / 2.0 W (2.0 W upgrade available only in certain  
countries)  
Frequency approvals (900 MHz)  
USA/CAN (-10), New Zealand/Australia (-20), Australia (-30)  
900 MHz transmitter radio power output 1.0 W (30 dBm)  
External GSM/GPRS, cellular phone support  
Supported for direct dial and Internet-based VRS correction  
streams  
Cellular phone or GSM/GPRS modem inside a TSC2 controller  
Receiver position update rate  
Correction data input  
1 Hz, 2 Hz, 5 Hz, 10 Hz, and 20 Hz positioning (varies by  
receiver model)  
CMR, CMR+, RTCM 2.0 (select RTCM 2.1), RTCM 2.1–2.3,  
RTCM 3.  
Correction data output  
Data outputs  
CMR, CMR+, RTCM 2.0 (select RTCM 2.1), RTCM 2.1–2.3.  
NMEA, GSOF, 1PPS Time Tags  
1 Bluetooth type approvals are country specific. For more information, contact your local Trimble office or  
representative.  
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10 Specifications  
GPS satellite signal tracking  
This table shows the GPS satellite signal tracking capability for each receiver in the  
SPSx51 Modular GPS receiver family.  
GPS signal type  
Class  
SPS551 SPS551H SPS651  
SPS751  
Basic base Basic rover  
SPS751  
SPS751 SPS851  
Max  
GPS signals  
L1/L2  
L2C  
9
9
9
9
9
8
9
9
8
9
9
8
9
Optional Optional Optional  
9
Optional  
L5  
8
8
8
GLONASS signals  
L1/L2  
WAAS  
EGNOS  
MSAS  
XP  
Optional Optional Optional  
8
8
8
Optional  
GPS SBAS corrections  
9
9
9
9
9
9
9
9
9
8
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
OmniSTAR  
corrections  
HP  
8
VBS  
8
Integrated radio options  
Except for the SPS551H, all the receiver configurations are available with or without  
internal radios with 450 MHz or 900 MHz frequency ranges. The SPS551H is not  
available with a radio.  
This table shows the radio options available for each receiver in the SPSx51 Modular  
GPS receiver family.  
Radio option  
SPS551 SPS551H SPS651  
SPS751  
Basic base Basic rover  
SPS751  
SPS751 SPS851  
Max  
No radio  
9
9
9
9
9
9
8
8
8
8
8
8
9
9
9
9
9
8
9
9
9
9
9
9
9
9
9
9
9
450 MHz Transmit  
450 MHz Receive  
900 MHz Transmit  
900 MHz Receive  
8
9
8
9
8
9
9
External 450 MHz Transmit Optional  
External 900 MHz Transmit Optional  
Optional Optional  
Optional Optional  
Optional  
Optional  
Optional Optional  
Optional Optional  
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Specifications 10  
Variable configuration options  
This table lists the default options for each receiver in the SPSx51 Modular GPS  
receiver family.  
Configuration  
option  
SPS551 SPS551H SPS651 SPS751 SPS751 SPS751 SPS851  
Basic  
base  
Basic  
rover  
Max  
Rover options  
Precise horizontal  
Precise vertical  
Precise heading/vector  
Location RTK  
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
RTCM DGPS  
9
9
RTK range limit  
Base options  
Static RTK  
2.4 km  
2.4 km  
None  
None  
9
9
9
9
9
9
9
9
Moving Base  
9
9
9
9
RTCM DGPS  
9
General options  
Data logging  
Optional Optional  
VRS support  
Location  
10 Hz  
Location  
10 Hz  
9
9
Max data rate  
10 Hz  
2 Hz  
2 Hz  
10 Hz  
20 Hz  
Upgrading the receiver  
You can upgrade the following receivers:  
SPS751 Basic base or SPS751 Basic rover to the SPS751 Max.  
The upgrade changes all standard options to SPS751 Max capability, and  
includes the radio option upgrade.  
The SPS551, SPS551H, and SPS651 can be upgraded with GLONASS and/or L2C.  
The SPS851 can be upgraded with GLONASS and/or L5.  
The SPSx51 with 450 MH UHF internal radios can be upgraded to 2 W  
transmission power if it is legally allowed in its country of use.  
The SPS751 Max and SPS851 can be upgraded to allow internal data logging.  
When you purchase the receiver upgrade, your Trimble dealer will provide you with a  
set of codes to change the receiver configuration. See also Appendix F, Upgrading the  
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10 Specifications  
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A P P E N D I X  
A
NMEA-0183 Output  
A
In this appendix:  
This appendix describes the formats of the  
subset of NMEA-0183 messages that are available  
for output by the receivers. For a copy of the  
NMEA-0183 Standard, go to the National Marine  
Electronics Association website at  
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A
NMEA-0183 Output  
NMEA-0183 message overview  
When NMEA-0183 output is enabled, a subset of NMEA-0183 messages can be output  
to external instruments and equipment connected to the receiver serial ports. These  
NMEA-0183 messages let external devices use selected data collected or computed by  
the GPS receiver.  
All messages conform to the NMEA-0183 version 3.01 format. All begin with $ and end  
with a carriage return and a line feed. Data fields follow comma (,) delimiters and are  
variable in length. Null fields still follow comma (,) delimiters but contain no  
information.  
An asterisk (*) delimiter and checksum value follow the last field of data contained in  
an NMEA-0183 message. The checksum is the 8-bit exclusive of all characters in the  
message, including the commas between fields, but not including the $ and asterisk  
delimiters. The hexadecimal result is converted to two ASCII characters (0–9, A–F).  
The most significant character appears first.  
The following table summarizes the set of NMEA messages supported by the receiver,  
and shows the page that contains detailed information about each message.  
Message  
Function  
Page  
Time, position, and fix related data  
GPS DOP and active satellites  
Position error statistics  
Number of SVs in view, PRN, elevation, azimuth, and SNR  
Heading from True North  
Time, yaw, tilt, range, mode, PDOP, and number of SVs for  
Moving Baseline RTK  
PTNL, BPQ  
Base station position and position quality indicator  
Time, position, position type and DOP values  
Local coordinate position output  
Time, locator vector, type and DOP values  
Heading Information  
Position, Velocity, and Time  
Rate of turn  
Actual track made good and speed over ground  
UTC day, month, and year, and local time zone offset  
To enable or disable the output of individual NMEA messages, do one of the following:  
Create an application file in the GPS Configurator software that contains NMEA  
output settings and then send the file to the receiver.  
Add NMEA outputs in the Serial outputs tab of the GPS Configurator software  
and then apply the settings. (You cannot use the GPS Configuration software to  
load application files to the SPSx51 Modular GPS receivers.)  
For SPSx51 Modular GPS receivers, set up the NMEA output using the keypad  
and display or a web browser.  
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NMEA-0183 Output  
A
Common message elements  
Each message contains:  
a message ID consisting of $GP followed by the message type. For example, the  
message ID of the GGA message is $GPGGA.  
a comma  
a number of fields, depending on the message type, separated by commas  
an asterisk  
a checksum value  
Below is an example of a simple message with a message ID ($GPGGA), followed by 13  
fields and a checksum value:  
$GPGGA,172814.0,3723.46587704,N,12202.26957864,W,2,6,1.2,18.893,M,-  
25.669,M,2.0,0031*4F  
Message values  
NMEA messages that the receiver generates contains the following values.  
Latitude and longitude  
Latitude is represented as ddmm.mmmm and longitude is represented as  
dddmm.mmmm, where:  
dd or ddd is degrees  
mm.mmmm is minutes and decimal fractions of minutes  
Direction  
Direction (north, south, east, or west) is represented by a single character: N, S, E, or W.  
Time  
Time values are presented in Universal Time Coordinated (UTC) and are represented  
as hhmmss.cc, where:  
hh is hours, from 00 through 23  
mm is minutes  
ss is seconds  
cc is hundredths of seconds  
NMEA messages  
When NMEA-0183 output is enabled, the following messages can be generated.  
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A
NMEA-0183 Output  
GGA  
Time, Position, and Fix Related Data  
An example of the GGA message string is shown below. Table A.1 describes the  
message fields.  
Note – The following data string exceeds the NMEA standard length.  
$GPGGA,172814.0,3723.46587704,N,12202.26957864,W,  
2,6,1.2,18.893,M,-25.669,M,2.0,0031*4F  
Table A.1  
GGA message fields  
Field  
Meaning  
0
1
2
3
Message ID $GPGGA  
UTC of position fix  
Latitude  
Direction of latitude:  
N: North  
S: South  
4
5
Longitude  
Direction of longitude:  
E: East  
W: West  
6
GPS Quality indicator:  
0: Fix not valid  
1: GPS fix  
2: Differential GPS fix, OmniSTAR VBS  
4: Real-Time Kinematic, fixed integers  
5: Real-Time Kinematic, float integers, OmniSTAR XP/HP or Location RTK  
7
Number of SVs in use, range from 00 through 12  
HDOP  
8
9
Orthometric height (MSL reference)  
M: unit of measure for orthometric height is meters  
Geoid separation  
10  
11  
12  
13  
M: geoid separation is measured in meters  
Age of differential GPS data record, Type 1 or Type 9. Null field when DGPS is  
not used.  
14  
Reference station ID, ranging from 0000 through 1023. A null field when any  
reference station ID is selected and no corrections are received .  
1
15  
The checksum data, always begins with *  
1When using OmniSTAR services, ID=100 for OmniSTAR VBS, ID=1000 for OmniSTAR HP, and ID=1008  
for OmniSTAR XP.  
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NMEA-0183 Output  
A
GSA  
GPS DOP and active satellites  
An example of the GSA message string is shown below. Table A.2 describes the  
message fields.  
$GPGSA,<1>,<2>,<3>,<3>,,,,,<3>,<3>,<3>,<4>,<5>,<6>*<7><CR><LF>  
Table A.2  
GSA message fields  
Field  
Meaning  
0
1
Message ID $GPGSA  
Mode 1, M = manual, A = automatic  
2
3
4
5
6
7
Mode 2, Fix type, 1 = not available, 2 = 2D, 3 = 3D  
PRN number, 01 through 32, of satellite used in solution, up to 12 transmitted  
PDOP-Position dilution of precision, 0.5 through 99.9  
HDOP-Horizontal dilution of precision, 0.5 through 99.9  
VDOP-Vertical dilution of precision, 0.5 through 99.9  
The checksum data, always begins with *  
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A
NMEA-0183 Output  
GST  
Position Error Statistics  
An example of the GST message string is shown below. Table A.3 describes the  
message fields.  
$GPGST,172814.0,0.006,0.023,0.020,273.6,0.023,0.020,0.031*6A  
Table A.3  
GST message fields  
Field  
Meaning  
0
1
2
Message ID $GPGST  
UTC of position fix  
RMS value of the pseudorange residuals; includes carrier phase residuals during  
periods of RTK(float) and RTK(fixed) processing  
3
4
5
6
7
8
9
Error ellipse semi-major axis 1 sigma error, in meters  
Error ellipse semi-minor axis 1 sigma error, in meters  
Error ellipse orientation, degrees from true north  
Latitude 1 sigma error, in meters  
Longitude 1 sigma error, in meters  
Height 1 sigma error, in meters  
The checksum data, always begins with *  
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NMEA-0183 Output  
A
GSV  
Satellite Information  
The GSV message string identifies the number of SVs in view, the PRN numbers,  
elevations, azimuths, and SNR values. An example of the GSV message string is shown  
below. Table A.4 describes the message fields.  
$GPGSV,4,1,13,02,02,213,,03,-3,000,,11,00,121,,14,13,172,05*67  
Table A.4  
GSV message fields  
Field  
Meaning  
0
Message ID $GPGSV  
1
Total number of messages of this type in this cycle  
Message number  
2
3
Total number of SVs visible  
4
SV PRN number  
5
Elevation, in degrees, 90° maximum  
Azimuth, degrees from True North, 000° through 359°  
SNR, 00–99 dB (null when not tracking)  
Information about second SV, same format as fields 4 through 7  
Information about third SV, same format as fields 4 through 7  
Information about fourth SV, same format as fields 4 through 7  
The checksum data, always begins with *  
6
7
8–11  
12–15  
16–19  
20  
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A
NMEA-0183 Output  
HDT  
Heading from True North  
The HDT string is shown below, and Table A.5 describes the message fields.  
$GPHDT,123.456,T*00  
Table A.5  
Heading from true north fields  
Field  
Meaning  
0
1
2
3
Message ID $GPHDT  
Heading in degrees  
T: Indicates heading relative to True North  
The checksum data, always begins with *  
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NMEA-0183 Output  
A
PTNL,AVR  
Time, Yaw, Tilt, Range for Moving Baseline RTK  
The PTNL,AVR message string is shown below, and Table A.6 describes the message  
fields.  
$PTNL,AVR,181059.6,+149.4688,Yaw,+0.0134,Tilt,,,60.191,3,2.5,6*00  
Table A.6  
AVR message fields  
Field  
Meaning  
0
1
2
3
4
5
6
7
8
9
Message ID $PTNL,AVR  
UTC of vector fix  
Yaw angle in degrees  
Yaw  
Tilt angle in degrees  
Tilt  
Reserved  
Reserved  
Range in meters  
GPS quality indicator:  
0: Fix not available or invalid  
1: Autonomous GPS fix  
2: Differential carrier phase solution RTK (Float)  
3: Differential carrier phase solution RTK (Fix)  
4: Differential code-based solution, DGPS  
10  
11  
12  
PDOP  
Number of satellites used in solution  
The checksum data, always begins with *  
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A
NMEA-0183 Output  
PTNL,BPQ  
Base station position and quality indicator  
This message describes the base station position and its quality. It is used when the  
moving base antenna position and quality are required on one serial port (along with a  
heading message) from a receiver in heading mode, typically the SPS551H.  
The PTNL,BPQ message string is shown below, and Table A.7 describes the message  
fields.  
$PTNL,BPQ,224445.06,021207,3723.09383914,N,12200.32620132,W,EHT-5.923,  
M,5*  
Table A.7  
BPQ message fields  
Field  
Meaning  
Talker ID  
BPQ  
0
1
2
UTC time of position fix, in hhmmss.ss format. Hours must be two numbers, so  
may be padded, for example, 7 is shown as 07.  
3
UTC date of position fix, in ddmmyy format. Day must be two numbers, so may  
be padded, for example, 8 is shown as 08.  
4
5
Latitude, in degrees and decimal minutes (ddmm.mmmmmmm)  
Direction of latitude:  
N: North  
S: South  
6
7
Longitude, in degrees and decimal minutes (dddmm.mmmmmmm). Should  
contain 3 digits of ddd.  
Direction of longitude:  
E: East  
W: West  
8
Height  
Ellipsoidal height of fix (antenna height above ellipsoid). Must start with EHT.  
9
M: ellipsoidal height is measured in meters  
10  
GPS quality indicator:  
0: Fix not available or invalid  
1: Autonomous GPS fix  
2: Differential SBAS, or OmniSTAR VBS  
4: RTK Fixed  
5: OmniSTAR XP, OmniSTAR HP, Float RTK, or Location RTK  
11  
The checksum data, always begins with *  
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NMEA-0183 Output  
A
PTNL,GGK  
Time, Position, Position Type, DOP  
An example of the PTNL,GGK message string is shown below. Table A.8 describes the  
message fields.  
$PTNL,GGK,453049.0,0,3728.455440850,N,12215.253291068,W,3,9,2.0,EHT35.742  
4,M*  
Table A.8  
PTNL,GGK message fields  
Field  
Meaning  
0
1
2
Talker ID $PTNL  
Message ID GGK  
UTC time of position fix, in hhmmmss.ss format. Hours must be two numbers,  
so may be padded, for example, 7 is shown as 07.  
3
UTC date of position fix, in ddmmyy format. Day must be two numbers, so may  
be padded, for example, 8 is shown as 08.  
4
5
Latitude, in degrees and decimal minutes (dddmm.mmmmmmm)  
Direction of latitude:  
N: North  
S: South  
6
7
Longitude, in degrees and decimal minutes (dddmm.mmmmmmm). Should  
contain three digits of ddd.  
Direction of longitude:  
E: East  
W: West  
8
GPS Quality indicator:  
0: Fix not available or invalid  
1: Autonomous GPS fix  
2: RTK float solution  
3: RTK fix solution  
4: Differential, code phase only solution (DGPS)  
5: SBAS solution – WAAS, EGNOS, MSAS  
6: RTK float or RTK location 3D Network solution  
7: RTK fixed 3D Network solution  
8: RTK float or RTK location 2D in a Network solution  
9: RTK fixed 2D Network solution  
10: OmniSTAR HP/XP solution  
11: OmniSTAR VBS solution  
12: Location RTK solution  
9
Number of satellites in fix  
10  
11  
12  
Ellipsoidal height of fix (antenna height above ellipsoid). Must start with EHT.  
M: ellipsoidal height is measured in meters  
The checksum data, always begins with *  
Note – The PTNL,GGK message is longer than the NMEA-0183 standard of 80 characters.  
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A
NMEA-0183 Output  
PTNL,PJK  
Local Coordinate Position Output  
An example of the PTNL,PJK message string is shown below. Table A.9 describes the  
message fields.  
$PTNL,PJK,010717.00,081796,+732646.511,N,+1731051.091,E,1,05,2.7,EHT-  
28.345,M*7C  
Table A.9  
PTNL,PJK message fields  
Field  
Meaning  
0
1
2
3
4
5
6
7
Message ID $PTNL,PJK  
UTC of position fix  
Date  
Northing, in meters  
Direction of Northing will always be N (North)  
Easting, in meters  
Direction of Easting will always be E (East)  
GPS Quality indicator:  
0: Fix not available or invalid  
1: Autonomous GPS fix  
2: RTK float solution  
3: RTK fix solution  
4: Differential, code phase only solution (DGPS)  
5: SBAS solution – WAAS, EGNOS, MSAS  
6: RTK Float 3D network solution  
7: RTK Fixed 3D network solution  
8: RTK Float 2D network solution  
9: RTK Fixed 2D network solution  
10: OmniSTAR HP/XP solution  
11: OmniSTAR VBS solution  
8
Number of satellites in fix  
9
DOP of fix  
10  
11  
12  
Ellipsoidal height of fix  
M: ellipsoidal height is measured in meters  
The checksum data, always begins with *  
Note – The PTNL,PJK message is longer than the NMEA-0183 standard of 80 characters.  
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NMEA-0183 Output  
A
PTNL,VGK  
Vector Information  
An example of the PTNL,VGK message string is shown below. Table A.10 describes the  
message fields.  
$PTNL,VGK,160159.00,010997,-0000.161,00009.985,-0000.002,3,07,1,4,M*0B  
Table A.10 PTNL,VGK message fields  
Field  
Meaning  
0
1
2
3
4
5
6
Message ID $PTNL,VGK  
UTC of vector in hhmmss.ss format  
Date in mmddyy format  
East component of vector, in meters  
North component of vector, in meters  
Up component of vector, in meters  
GPS Quality indicator:  
0: Fix not available or invalid  
1: Autonomous GPS fix  
2: RTK float solution  
3: RTK fix solution  
4: Differential, code phase only solution (DGPS)  
5: SBAS solution – WAAS, EGNOS, MSAS  
6: RTK Float 3D network solution  
7: RTK Fixed 3D network solution  
8: RTK Float 2D network solution  
9: RTK Fixed 2D network solution  
10: OmniSTAR HP/XP solution  
11: OmniSTAR VBS solution  
7
Number of satellites if fix solution  
DOP of fix  
8
9
M: Vector components are in meters  
The checksum data, always begins with *  
10  
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A
NMEA-0183 Output  
PTNL,VHD  
Heading Information  
An example of the PTNL,VHD message string is shown below. Table A.11 describes the  
message fields.  
$PTNL,VHD,030556.00,093098,187.718,-22.138,-76.929,-  
5.015,0.033,0.006,3,07,2.4,M*22  
Table A.11 PTNL,VHD message fields  
Field  
Meaning  
0
1
2
3
4
5
6
7
8
9
Message ID $PTNL,VHD  
UTC of position in hhmmss.ss format  
Date in mmddyy format  
Azimuth  
ΔAzimuth/ΔTime  
Vertical Angle  
ΔVertical/ΔTime  
Range  
ΔRange/ΔTime  
GPS Quality indicator:  
0: Fix not available or invalid  
1: Autonomous GPS fix  
2: RTK float solution  
3: RTK fix solution  
4: Differential, code phase only solution (DGPS)  
5: SBAS solution – WAAS, EGNOS, MSAS  
6: RTK Float 3D network solution  
7: RTK Fixed 3D network solution  
8: RTK Float 2D network solution  
9: RTK Fixed 2D network solution  
10: OmniSTAR HP/XP solution  
11: OmniSTAR VBS solution  
10  
11  
12  
Number of satellites used in solution  
PDOP  
The checksum data, always begins with *  
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NMEA-0183 Output  
A
RMC  
Position, Velocity, and Time  
The RMC string is shown below, and Table A.12 describes the message fields.  
$GPRMC,123519,A,4807.038,N,01131.000,E,022.4,084.4,230394,003.1,W*6A  
Table A.12 GPRMC message fields  
Field  
Meaning  
0
1
2
3
4
5
6
7
8
9
Message ID $GPRMC  
UTC of position fix  
Status A=active or V=void  
Latitude  
Longitude  
Speed over the ground in knots  
Track angle in degrees (True)  
Date  
Magnetic variation in degrees  
The checksum data, always begins with *  
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A
NMEA-0183 Output  
ROT  
Rate and Direction of Turn  
The ROT string is shown below, and Table A.13 describes the message fields.  
$GPROT,35.6,A*4E  
Table A.13 ROT message fields  
Field  
Meaning  
0
1
2
Message ID $GPROT  
Rate of turn, degrees/minutes, "–" indicates bow turns to port  
A: Valid data  
V: Invalid data  
3
The checksum data, always begins with *  
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NMEA-0183 Output  
A
VTG  
Track Made Good and Speed Over Ground  
An example of the VTG message string is shown below, and Table A.14 describes the  
message fields.  
$GPVTG,,T,,M,0.00,N,0.00,K*4E  
Table A.14 VTG message fields  
Field  
Meaning  
0
1
2
3
4
5
6
7
8
9
Message ID $GPVTG  
Track made good (degrees true)  
T: track made good is relative to true north  
Track made good (degrees magnetic)  
M: track made good is relative to magnetic north  
Speed, in knots  
N: speed is measured in knots  
Speed over ground in kilometers/hour (kph)  
K: speed over ground is measured in kph  
The checksum data, always begins with *  
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A
NMEA-0183 Output  
ZDA  
UTC Day, Month, And Year, and Local Time Zone Offset  
An example of the ZDA message string is shown below, and Table A.15 describes the  
message fields.  
$GPZDA,172809,12,07,1996,00,00*45  
Table A.15 ZDA message fields  
Field  
Meaning  
0
1
2
3
4
5
6
7
Message ID $GPZDA  
UTC  
Day, ranging between 01 and 31  
Month, ranging between 01 and 12  
Year  
Local time zone offset from GMT, ranging from 00 through 13 hours  
Local time zone offset from GMT, ranging from 00 through 59 minutes  
The checksum data, always begins with *  
Fields 5 and 6 together yield the total offset. For example, if field 5 is –5 and field 6 is  
+15, local time is 5 hours and 15 minutes earlier than GMT.  
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A P P E N D I X  
B
GSOF Messages  
B
In this appendix:  
This appendix provides information on the  
General Serial Output Format (GSOF) messages.  
GSOF messages are a Trimble proprietary format  
and can be used to send information such as  
position and status to a third-party device.  
For information on how to output GSOF  
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B
GSOF Messages  
Supported message types  
This table summarizes the GSOF messages that are supported by the receiver, and  
shows the page that contains detailed information about each message.  
Message  
Description  
Page  
Position time  
Latitude, longitude, height  
Earth-Centered, Earth-Fixed position  
Earth-Centered, Earth-Fixed Delta position  
Tangent Plane Delta  
Velocity data  
PDOP info  
Position Sigma info  
SV Brief info  
SV Detailed info  
Current UTC time  
BATT/MEM  
ATTITUDE  
Receiver battery and memory status  
Attitude info  
Base station position and its quality  
General Serial Output Format  
Table B.1  
Report packet 40h structure (GENOUT)  
Byte  
Item  
Type  
Value  
Meaning  
0
1
2
3
4
STX  
CHAR 02h  
Start transmission.  
STATUS  
PACKET TYPE  
LENGTH  
CHAR See Table B.2 Receiver status code.  
CHAR 40h  
CHAR 00h–FAh  
CHAR  
Report Packet 40h (GENOUT).  
Data byte count.  
TRANSMISSION  
NUMBER  
Unique number assigned to a group  
of record packet pages. Prevents  
page mismatches when multiple sets  
of record packets exist in output  
stream.  
5
6
PAGE INDEX  
CHAR 00h–FFh  
Index of current packet page.  
MAX PAGE INDEX CHAR 00h–FFh  
Maximum index of last packet in one  
group of records.  
One or more GSOF messages  
Output record  
type  
CHAR 01h  
CHAR 0Ah  
For example, Time (Type 1 Record).  
Bytes in record.  
Record length  
Various fields depending on Output record type  
There can be multiple records in one GENOUT packet. There could be multiple GENOUT  
packets per epoch. Records may be split over two consecutive packets.  
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GSOF Messages  
B
Table B.1  
Report packet 40h structure (GENOUT)  
Byte  
Item  
Type  
Value  
Meaning  
Length + 4 CHECKSUM  
(Status + type + length + data bytes)  
modulo 256  
Length + 5 ETX (03h)  
End transmission  
Each message begins with a 4-byte header, followed by the bytes of data in each packet.  
The packet ends with a 2-byte trailer. Byte 3 is set to 0 (00h) when the packet contains  
no data. Most data is transmitted between the receiver and remote device in binary  
format.  
Table B.2  
Receiver Status code  
Byte  
Message  
Description  
number  
Bit 0  
1
Reserved  
Bit 1  
1
Low battery  
Reserved  
Bit 2–7  
0–63  
Reading binary values  
The receivers store numbers in Motorola format. The byte order of these numbers is  
the opposite of what personal computers (PCs) expect (Intel format). To supply or  
interpret binary numbers (8-byte DOUBLES, 4-byte LONGS, and 2-byte INTEGERS), the  
byte order of these values must be reversed. This section contains a detailed  
description of the Motorola format.  
INTEGER data types  
The INTEGER data types (CHAR, SHORT, and LONG) can be signed or unsigned. By  
default, they are unsigned. All integer data types use two’s complement representation.  
The following table lists the integer data types.  
Type  
# of bits  
Range of values (Signed)  
–128 to 127  
(Unsigned)  
0 to 255  
CHAR  
SHORT  
LONG  
8
16  
32  
–32768 to 32767  
0 to 65535  
–2147483648 to 2147483647  
0 to 4294967295  
FLOATING-POINT data types  
Floating-point data types are stored in the IEEE SINGLE and DOUBLE precision formats.  
Both formats have a sign bit field, an exponent field, and a fraction field. The fields  
represent floating-point numbers in the following manner:  
Floating-Point Number = <sign> 1.<fraction field> x 2(<exponent field> - bias)  
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B
GSOF Messages  
Sign bit field  
The sign bit field is the most significant bit of the floating-point number. The  
sign bit is 0 for positive numbers and 1 for negative numbers.  
Fraction field  
The fraction field contains the fractional part of a normalized number.  
Normalized numbers are greater than or equal to 1 and less than 2. Since all  
normalized numbers are of the form 1.XXXXXXXX, the 1 becomes implicit and  
is not stored in memory. The bits in the fraction field are the bits to the right of  
the binary point, and they represent negative powers of 2.  
For example:  
0.011 (binary) = 2-2 + 2-3 = 0.25 + 0.125 = 0.375  
Exponent field  
The exponent field contains a biased exponent; that is, a constant bias is  
subtracted from the number in the exponent field to yield the actual exponent.  
(The bias makes negative exponents possible.)  
If both the exponent field and the fraction field are zero, the floating-point  
number is zero.  
NaN  
A NaN (Not a Number) is a special value which is used when the result of an  
operation is undefined. For example, adding positive infinity to negative infinity  
results in a NaN.  
FLOAT data type  
The FLOAT data type is stored in the IEEE single-precision format which is 32 bits long.  
The most significant bit is the sign bit, the next 8 most significant bits are the exponent  
field, and the remaining 23 bits are the fraction field. The bias of the exponent is 127.  
The range of single-precision format values is from 1.18 x 10–38 to 3.4 x 1038. The  
floating-point number is precise to 6 decimal digits.  
31  
30  
23 22  
Fraction  
0
S
Exp. + Bias  
0 000 0000 0 000 0000 0000 0000 0000 0000 = 0.0  
0 011 1111 1 000 0000 0000 0000 0000 0000 = 1.0  
1 011 1111 1 011 0000 0000 0000 0000 0000 = -1.375  
1 111 1111 1 111 1111 1111 1111 1111 1111 = NaN  
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GSOF Messages  
B
DOUBLE  
The DOUBLE data type is stored in the IEEE double-precision format which is 64 bits  
long. The most significant bit is the sign bit, the next 11 most significant bits are the  
exponent field, and the remaining 52 bits are the fractional field. The bias of the  
exponent is 1023. The range of single precision format values is from 2.23 × 10–308 to  
1.8 × 10308. The floating-point number is precise to 15 decimal digits.  
63  
62  
52 51  
Fraction  
0
S
Exp. + Bias  
0 000 0000 0000 0000 0000 ... 0000 0000 0000 = 0.0  
0 011 1111 1111 0000 0000 ... 0000 0000 0000 = 1.0  
1 011 1111 1110 0110 0000 ... 0000 0000 0000 = -0.6875  
1 111 1111 1111 1111 1111 ... 1111 1111 1111 = NaN  
GSOF message definitions  
When GSOF output is enabled, the following messages can be generated.  
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B
GSOF Messages  
TIME  
This message describes position time information. It contains the following data:  
GPS time, in milliseconds of GPS week  
GPS week number  
Number of satellites used  
Initialization counter  
Table B.3  
Time (Type 1 record)  
Type  
Field Item  
Value  
01h  
Meaning  
0
Output record type  
Char  
Char  
Long  
Short  
Char  
Position time output record  
Bytes in record  
1
Record length  
0Ah  
2–5  
6–7  
8
GPS time (ms)  
msecs  
number  
00h-0Ch  
GPS time, in milliseconds of GPS week  
GPS week count since January 1980  
GPS week number  
Number of SVs used  
Number of satellites used to determine the  
position (0-12)  
9
Position flags 1  
Position flags 2  
Initialized number  
Char  
Char  
Char  
00h-FFh  
Reports first set of position attribute flag  
values  
10  
11  
Reports second set of position attribute flag  
values  
Increments with each initialization (modulo  
256)  
LLH  
This message describes latitude, longitude, and height. It contains the following data:  
WGS-84 latitude and longitude, in radians  
WGS-84 height, in meters  
Table B.4  
Latitude, longitude, height (Type 2 record)  
Field  
0
Item  
Type  
Value  
02h  
Meaning  
Output record type Char  
Latitude, longitude, and height output record  
Bytes in record  
1
Record length  
Latitude  
Char  
18h  
2–9  
Double Radians  
Double Radians  
Double Meters  
Latitude from WGS-84 datum  
Longitude from WGS-84 datum  
Height from WGS-84 datum  
10–17 Longitude  
18–25 Height  
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GSOF Messages  
B
ECEF  
This message describes the ECEF position. It contains the following data:  
Earth-Centered, Earth-Fixed X, Y, Z coordinates, in meters  
Table B.5  
ECEF position (Type 3 record)  
Item Type Value  
Output record type Char  
Field  
Meaning  
0
03h  
Earth-Centered, Earth-Fixed (ECEF) position output  
record  
1
Record length  
Char  
18h  
Bytes in record  
2–9  
X
Y
Z
Double Meters  
Double Meters  
Double Meters  
WGS-84 ECEF X-axis coordinate  
WGS-84 ECEF Y-axis coordinate  
WGS-84 ECEF Z-axis coordinate  
10–17  
18–25  
ECEF DELTA  
This message describes the ECEF Delta position. It contains the following data:  
Earth-Centered, Earth-Fixed X, Y, Z deltas between the rover and base position,  
in meters.  
Table B.6  
ECEF Delta (Type 6 record)  
Item Type Value  
Output record type Char  
Field  
0
Meaning  
06h  
18h  
Earth-Centered, Earth-Fixed (ECEF) Delta output record  
Bytes in record  
1
Record length  
Delta X  
Char  
2–9  
Double Meters  
Double Meters  
Double Meters  
ECEF X-axis delta between rover and base station  
positions  
10–17 Delta Y  
18–25 Delta Z  
ECEF Y-axis delta between rover and base station  
positions  
ECEF Z-axis delta between rover and base station  
positions  
NEU DELTA  
This message contains Tangent Plane Delta information. It contains the following  
data:  
North, East, and Up deltas of the vector from the base to the rover (in meters)  
projected onto a plane tangent to the WGS-84 ellipsoid at the base receiver.  
Note – These records are only output if a valid DGPS/RTK solution is computed.  
Table B.7  
NEU Delta (Type 7 record)  
Field  
Item  
Output record type Char  
Record length Char  
Type  
Value  
07h  
Meaning  
0
1
Tangent Plane Delta output record  
Bytes in record  
18h  
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B
GSOF Messages  
Table B.7  
NEU Delta (Type 7 record)  
Field  
Item  
Type  
Value  
Meaning  
2–9  
Delta east  
Double meters  
East component of vector from base station to rover,  
projected onto a plane tangent to the WGS-84 ellipsoid  
at the base station  
10–17 Delta north  
18–25 Delta up  
Double meters  
Double meters  
North component of tangent plane vector  
Difference between ellipsoidal height of tangent plane  
at base station and a parallel plane passing through  
rover point  
Velocity  
This message provides velocity information. It contains the following data:  
Horizontal velocity, in meters per second  
Vertical velocity, in meters per second  
Heading, in radians, referenced to WGS-84 True North  
Table B.8  
Velocity (Type 8 record)  
Field  
0
Item  
Type  
Value  
Meaning  
Output record type Char  
08h  
Velocity data output record  
Bytes in record  
1
Record length  
Velocity flags  
Speed  
Char  
Char  
Float  
Float  
Float  
0Dh  
2
Meters per second  
Radians  
Velocity status flags  
Horizontal speed  
3–6  
7–10  
Heading  
True north heading in the WGS-84 datum  
Vertical velocity  
11–14 Vertical velocity  
Meters per second  
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GSOF Messages  
B
PDOP  
This message describes the PDOP information. It contains the following data:  
PDOP  
HDOP  
VDOP  
TDOP  
Table B.9  
PDOP (Type 9 record)  
Field  
0
Item  
Type  
Value  
09h  
Meaning  
Output record type Char  
PDOP information output record  
Bytes in record  
1
Record length  
PDOP  
Char  
Float  
Float  
Float  
Float  
10h  
2–5  
6–9  
Positional Dilution of Precision  
Horizontal Dilution of Precision  
Vertical Dilution of Precision  
Time Dilution of Precision  
HDOP  
10–13 VDOP  
14–17 TDOP  
SIGMA  
This message describes the Position Sigma information. It contains the following data:  
Position RMS  
Sigma east, in meters  
Sigma north, in meters  
Sigma up, in meters  
Covariance east-north  
Error Ellipse Semi-major axis, in meters  
Error Ellipse Semi-minor axis, in meters  
Orientation of Semi-major axis in degrees from True North  
Unit variance  
Number of epochs  
Table B.10  
Sigma (Type 12 record)  
Field  
0
Item  
Type  
Value  
0Ch  
Meaning  
Output record type Char  
Position sigma information output record  
Bytes in record  
1
Record length  
Position RMS  
Char  
Float  
26h  
2–5  
Root means square of position error calculated  
for overdetermined positions  
6–9  
Sigma east  
Float  
Float  
Float  
Meters  
Meters  
number  
10–13 Sigma north  
14–17 Covar. east-north  
Covariance east-north (dimensionless)  
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B
GSOF Messages  
Table B.10  
Sigma (Type 12 record) (continued)  
Field  
Item  
Type  
Float  
Float  
Float  
Float  
Value  
Meaning  
18–21 Sigma up  
Meters  
Meters  
Meters  
degrees  
22–25 Semi-major axis  
26–29 Semi-minor axis  
30–33 Orientation  
Semi-major axis of error ellipse  
Semi-minor axis of error ellipse  
Orientation of semi-minor axis, clockwise from  
True North  
34–37 Unit variance  
Float  
Valid only for over-determined solutions. Unit  
variance should approach 1.0 value. A value of  
less than 1.0 indicates that apriori variances are  
too pessimistic.  
30–39 Number of epochs short  
count  
Number of measurement epochs used to  
compute the position. Could be greater than 1  
for positions subjected to static constraint.  
Always 1 for kinematic.  
SV Brief  
This message provides brief satellite information. It contains the following data:  
Number of satellites tracked  
The PRN number of each satellite  
Flags indicating satellite status  
Table B.11  
SV brief (Type 13 record)  
Type Value  
Field Item  
Meaning  
0
1
2
Output record type Char  
0Dh  
Brief satellite information output record  
Bytes in record  
Record length  
Number of SVs  
Char  
Char  
1
00h-18h  
Number of satellites included in record  
The following bytes are repeated for Number of SVs  
PRN  
Char  
Char  
Char  
01h-20h  
Pseudorandom number of satellites (1-32)  
First set of satellite status bits  
SV Flags1  
SV Flags2  
Second set of satellite status bits  
1
Includes all tracked satellites, all satellites used in the position solution, and all satellites in view.  
SV Detail  
This message provides detailed satellite information. It contains the following data:  
Number of satellites tracked  
The PRN number of each satellite  
Flags indicating satellite status  
Elevation above horizon, in degrees  
Azimuth from True North, in degrees  
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GSOF Messages  
B
Signal-to-noise ratio (SNR) of L1 signal  
Signal-to-noise ratio (SNR) of L2 signal  
Table B.12  
SV detail (Type 14 record)  
Field  
Item  
Type  
Value  
0Eh  
Meaning  
Detailed satellite information output record  
0
Output record  
type  
Char  
1
Record length  
Number of SVs  
Char  
Char  
1 + 8×(number of SVs) Bytes in record  
00h-18h Number of satellites included in record  
1
2–9  
The following bytes are repeated for Number of SVs  
PRN  
Char  
Char  
Char  
Char  
Short  
Char  
01h-20h  
Pseudorandom number of satellites (1–32)  
First set of satellite status bits  
Flags1  
Degrees  
Flags2  
Second set of satellite status bits  
Elevation  
Azimuth  
SNR L1  
Angle of satellite above the horizon  
Azimuth of satellite from True North  
Signal-to-noise ratio of L1 signal (multiplied  
Degrees  
dB * 4  
2
by 4)  
SNR L2  
Char  
dB * 4  
Signal-to-noise ratio of L2 signal (multiplied  
by 4)  
2
1Includes all tracked satellites, all satellites used in the position solution, and all satellites in view.  
2THe SNR L1 and SNR L2 items are set to zero for satellites that are not tracked on the current frequency.  
UTC  
This message describes current time information. It contains the following data:  
GPS time, in milliseconds of GPS week  
GPS week number  
GPS to UTC time offset, in seconds  
Table B.13  
UTC (Type 16 record)  
Item Type Value  
Output record type Char  
Record length Char  
Field  
0
Meaning  
10h  
09h  
1
Bytes in record  
2–5  
GPS millisecond of Long msecs  
week  
Time when packet is sent from the receiver, in GPS  
milliseconds of week  
6–7  
8–9  
10  
GPS week number Short number  
Week number since start of GPS time  
GPS to UTC time offset  
UTC offset  
Flags  
Short seconds  
Char  
See Table B.19 Flag bits indicating validity of Time and UTC offsets  
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B
GSOF Messages  
Batt/Mem  
This message provides information relating to the receiver battery and memory. It  
contains the following data:  
Remaining battery power  
Remaining memory  
Table B.14  
Batt/Mem (Type 37 record)  
Field  
0
Item  
Type  
Value  
25h  
Meaning  
Output record type Char  
1
Record length  
Char  
0Ah  
Bytes in record  
2–3  
4–11  
Battery capacity  
Unsigned short percentage  
Remaining battery capacity in percentage  
Remaining memory Double  
hours  
Estimated remaining data logging time in  
hours  
Attitude  
This message provides attitude information relating to the vector between the Heading  
antenna and the Moving Base antenna. It contains the following data:  
Tilt or vertical angle, in radians, from the Heading antenna to the Moving Base  
antenna relative to a horizontal plane through the Heading antenna  
Heading or yaw, in radians, relative to True North  
Range or slope distance between the Heading antenna and the Moving Base  
antenna  
Table B.15  
Attitude (Type 27 record)  
Field  
Item  
Type  
Value  
1Bh  
Meaning  
0
Output record type Char  
Attitude information  
Bytes in record  
1
Record length  
GPS time  
Flags  
Char  
Long  
Char  
2Ah  
2–5  
6
msecs  
GPS time in milliseconds of GPS week  
See Table B.23 Flag bits indicating validity of attitude components  
00h-0Ch Number of satellites used to calculate attitude  
7
Number of SVs used Char  
8
Calculation mode  
Reserved  
Char  
See Table B.24 Positioning mode  
Reserved  
9
10–17 Tilt  
18–25 Yaw  
Double radians  
Double radians  
Tilt relative to horizontal plane  
Rotation about the vertical axis relative to True  
North  
26–33 Reserved  
34–41 Range  
42–43 PDOP  
Reserved  
Double meters  
Distance between antennas  
Position Dilution of Precision  
Short  
0.1  
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GSOF Messages  
B
BASE POSITION AND QUALITY INDICATOR  
This message describes the base station position and its quality. It is used when the  
moving base antenna position and quality are required on one serial port (along with a  
heading message) from a receiver in heading mode, typically the SPS551H.  
Table B.16  
Base position and quality indicator (Type 41 record)  
Field Item  
Type  
Char  
Value  
01h  
Meaning  
0
Output record type  
Position time output record  
Bytes in record  
1
Record length  
GPS time (ms)  
GPS week number  
Latitude  
Char  
0Ah  
2–5  
6–7  
8
Long  
Short  
Double  
msecs  
number  
Radians  
GPS time, in milliseconds of GPS week  
GPS week count since January 1980  
The WGS-84 latitude, in radians, of the  
moving base antenna  
9
Longitude  
Double  
Double  
Char  
Radians  
The WGS-84 longitude, in radians, of the  
moving base antenna  
10  
11  
Height  
Meters  
The WGS-84 height, in meters, of the moving  
base antenna  
Quality indicator  
The quality of the base station position:  
0: Fix not available or invalid  
1: Autonomous GPS fix  
2: Differential SBAS or OmniSTAR VBS  
4: RTK Fixed  
5: OmniSTAR XP, OmniSTAR HP, Float RTK,  
or Location RTK  
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B
GSOF Messages  
Flags  
Table B.17  
Position flags 1: bit values  
Bit  
Meaning  
0
New position  
0: No. 1: Yes.  
1
2
3
4
5
6
7
Clock fix calculated for current position  
0: No. 1: Yes.  
Horizontal coordinates calculated this position  
0: No. 1: Yes.  
Height calculated this position  
0: No. 1: Yes.  
Weighted position  
0: No. 1: Yes.  
Overdetermined position  
0: No. 1: Yes.  
Ionosphere-free position  
0: No. 1: Yes.  
Position uses filtered L1 pseudoranges  
0: No. 1: Yes.  
Table B.18  
Position flags 2: bit values  
Bit  
Meaning  
0
Differential position  
0: Differential position is an autonomous or a WAAS solution.  
1: Position is a differential solution.  
1
2
Differential position method  
0: Code  
1: Phase including RTK, HP or XP OmniSTAR (VBS is not derived from Phase).  
Differential position method  
0: Code (DGPS) or a float position (RTK). Uncorrected position is Autonomous  
(if bit 0 = 0).  
1: Position is fixed integer phase position (RTK). Uncorrected position is WAAS  
(if bit 0 = 0).  
3
OmniSTAR solution  
0: Not active  
1: OmniSTAR differential solution (including HP, XP, and VBS)  
4
5
6
7
Position determined with static as a constraint  
0: No. 1: Yes.  
Position is network RTK solution  
0: No. 1: Yes.  
Position is Location RTK  
0: No. 1: Yes.  
Reserved (set to zero)  
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GSOF Messages  
B
Table B.19  
Flags: Bit values  
Bit  
Meaning  
0
Time information (week and millisecond of week) validity  
0: Not valid  
1: Valid  
1
UTC offset validity  
0: Not valid  
1: Valid  
Table B.20  
Velocity flags: Bit values  
Bit  
Meaning  
0
Velocity data validity  
0: Not valid  
1: Valid  
1
Velocity computation  
0: Computed from doppler  
1: Computed from consecutive measurements  
2–7  
Reserved (set to zero)  
Table B.21  
SV flags: 1 bit values  
Bit  
Meaning  
0
Satellite Above Horizon  
0: No. 1: Yes.  
1
2
3
4
5
6
7
Satellite Currently Assigned to a Channel (trying to track)  
0: No. 1: Yes.  
Satellite Currently Tracked on L1 Frequency  
0: No. 1: Yes.  
Satellite Currently Tracked on L2 Frequency  
0: No. 1: Yes.  
Satellite Reported at Base on L1 Frequency  
0: No. 1: Yes.  
Satellite Reported at Base on L2 Frequency  
0: No. 1: Yes.  
Satellite Used in Position  
0: No. 1: Yes.  
Satellite Used in Current RTK Process (Search, Propagate, Fix Solution)  
0: No. 1: Yes.  
Table B.22  
SV flags: 2 bit value  
Bit  
Meaning  
0
Satellite Tracking P-Code on L1 Band  
0: No. 1: Yes.  
1
Satellite Tracking P-Code on L2 Band  
0: No. 1: Yes.  
2–7  
Reserved. Set to zero.  
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B
GSOF Messages  
Table B.23  
Attitude flags  
Bit  
Meaning  
0
Calibrated  
0: No. 1: Yes.  
1
2
Tilt valid  
0: No. 1: Yes.  
Yaw valid  
0: No. 1: Yes.  
3
4
Reserved  
Range valid  
0: No. 1: Yes.  
5–7  
Reserved  
Table B.24  
Attitude calculation flags  
Bit  
Meaning  
0
0: No position  
1: Autonomous position  
2: RTK/Float position  
3: RTK/Fix position  
4: DGPS position  
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A P P E N D I X  
C
Adding Internal Radio Frequencies  
C
In this appendix:  
If you have the optional internal 450 MHz radio  
in your GPS receiver, use the WinFlash utility to  
add the relevant receive frequencies to the  
default list of frequencies. To install the WinFlash  
You can also use the web interface to add and  
manage receive 450 MHz frequencies.  
If you have a receiver with the transmit option,  
Trimble must specify and configure the  
(FCC-approved) transmit broadcast frequencies  
at the factory. You cannot configure these  
yourself. If extra Transmit frequencies are  
obtained once you have your receiver, then  
contact your local Trimble authorized dealer to  
have the extra frequencies added. The dealer will  
provide you with a Set file, which you can transfer  
to the receiver using the WinFlash utility.  
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C
Adding Internal Radio Frequencies  
Adding receive frequencies for the 450 MHz internal radio  
1. Start the WinFlash utility. The Device Configuration screen appears.  
2. From the Device type list, select the appropriate receiver.  
3. From the PC serial port field, select the serial (COM) port on the computer that  
the receiver is connected to.  
4. Click Next. The Operation Selection dialog appears. The Operations list shows all  
of the supported operations for the selected device. A description of the selected  
operation is shown in the Description field.  
5. Select Configure Radio  
Settings and then click  
Next. The Internal  
Transceiver Configuration  
dialog appears:  
6. In the Wireless Format  
group, select the  
appropriate channel and  
wireless mode. The  
Wireless mode must be  
the same for all radios in  
your network.  
7. In the Specify Frequency  
field, enter the frequency  
you want to add.  
8. Click Add. The new  
frequency appears in the  
Selected Frequencies list.  
Note – The programmed  
frequencies must conform to the  
channel spacing and minimum  
tuning requirements for the  
radio. To view this information,  
click Radio Info. You can select  
12.5 kHz or 25 kHz channel  
spacing. All radios in your network must use the same channel spacing.  
9. Once you have configured all the frequencies that you require, click OK.  
The WinFlash utility updates the receiver radio frequencies and then restarts  
the receiver.  
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Adding Internal Radio Frequencies  
C
Setting UHF reception radio frequencies using the web  
interface  
To enter your own Receive (Rx) frequency using the web interface:  
1. Select the Radio menu.  
2. Select the Frequency Management submenu:  
3. Make a note of the details shown in the Frequency range and Tuning step fields.  
Any new frequencies must be within the range shown and must also be a  
multiple of the Khz shown in the Tuning step field.  
4. Select the Add Channel option and then enter the new channel frequency.  
5. Click OK.  
To delete a channel frequency :  
1. Select the Delete channel option.  
2. Select a channel to delete from the list that appears.  
You cannot add or delete Transmit channels using the web interface.  
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C
Adding Internal Radio Frequencies  
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A P P E N D I X  
D
Transmitting Corrections  
D
In this chapter:  
This chapter details how to transmit corrections  
over a construction site through 900 MHz and  
450 MHz radios from the same base station.  
Three scenarios and the solutions to each are  
explained.  
corrections from a SNB900 radio  
to an HPB450 or TRIMMARK 3  
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D
Transmitting Corrections  
Scenario 1: Outputting corrections using an HPB450  
radio-modem  
A Construction base station such as the SPS851 has an internal 900 MHz radio and you  
want to also transmit corrections on a Trimble HPB450 radio-modem connected to the  
SPS851 receiver.  
Solution  
The HPB450 radio comes with a 5-pin Lemo to 7-pin Lemo connector with a power  
connection lead:  
1. Connect the 7-pin Lemo connector to the connector on the receiver.  
2. Connect the 5-pin Lemo connector to the HPB450 radio.  
3. Connect the DC power lead to an external power source.  
4. Turn on the HPB450 radio.  
If the HPB450 radio has the 5-pin Lemo connector to 9-pin D-sub connector cable:  
1. Connect the 9-pin D connector to the 26-pin to 9-pin D-sub adaptor on the  
receiver.  
2. Connect the 5-pin Lemo connector to the HPB450 radio.  
3. Connect the DC power lead to an external power source.  
4. Turn on the HPB450 radio.  
To configure the system, do one of the following:  
Use the Trimble SCS900 Site Controller software to connect to the receiver. Set  
up the base station with the external radio. The SCS900 software will locate the  
HPB450 radio and then allow you to set the radio channel. Then, use the front  
panel of the receiver to select Radio and Lemo (R+L) to then turn on the internal  
900 MHz radio transmissions. If using the 9-pin D-sub connector, select Radio  
and Modem Port (R+M).  
Use the web interface to access the SPS851 setup. Select I/O Configuration / Port  
Configuration. Select the Serial 1 / Lemo option and select corrections to be sent  
on the Lemo port at those baud rate settings (the HPB450 serial interface is  
shipped with the default rates 38400 8/N/1). While in the Port Configuration  
menu, also set the internal radio to transmit corrections.  
Use the front panel of the receiver to set up the Lemo port and to select the radio  
on which to output the data (shown as R+L or R+M on the receiver display).  
Configuration software accompanies the HPB450 radio if you need to change the serial  
connection baud rate.  
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Transmitting Corrections  
D
Scenario 2: Outputting corrections using a TRIMMARK 3 radio  
A Construction base station such as the SPS851 has an internal 900 MHz radio and you  
want to transmit corrections on a Trimble TRIMMARK 3 radio connected to the  
SPS851 receiver.  
Solution  
The TRIMMARK 3 radio comes with both a 7-pin Lemo to 7-pin Lemo cable and a  
7-pin Lemo to 9-pin D-sub cable.  
To connect the TRIMMARK 3 radio to the SPS851 receiver, do one of the following:  
Use the 7-pin Lemo (SPS851) to 7-pin Lemo (TRIMMARK 3) cable.  
Use the Lemo-to-Lemo cable.  
Use the 7-pin Lemo to 9-pin D-sub cable and then connect to the Modem port  
(9-pin D-sub connector) on the SPS851 adaptor.  
To configure the system, do one of the following:  
Use the SCS900 Site Controller software to connect to the receiver (either by  
cable or Bluetooth wireless technology). Start the base station and then  
configure RTK messages to be transmitted through an external radio. The  
SCS900 software will locate the TRIMMARK 3 radio and then allow you to set  
the radio channel. Then, use the front panel of the receiver to select Radio and  
Lemo (R+L) or (R+M) to turn on the internal 900 MHz radio transmissions.  
Use the web interface to access the SPS851 setup. Select I/O Configuration / Port  
Configuration. Select the Serial 1 / Lemo option and select corrections to be sent  
on the Lemo port at those baud rate settings. If using 9-pin D-sub, then use the  
Modem port. While in the Port Configuration menu, also set the internal radio to  
transmit corrections.  
Use the front panel of the receiver to set up the Lemo port and to select the radio  
on which to output the data (shown as R+L or R+M on the receiver display).  
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D
Transmitting Corrections  
Scenario 3: Outputting corrections from a SNB900 radio to an  
HPB450 or TRIMMARK 3 radio  
Output corrections from the Trimble SNB900 radio through the Lemo port to an  
HPB450 or TRIMMARK 3 radio. This is especially useful when using a Smart GPS  
antenna such as the Trimble SPS881 and the construction site requires dual  
frequencies (450 MHz and 900 MHz) to be broadcast.  
Solution  
To configure the system:  
1. Use a cable to connect the SNB900 radio-modem (Lemo Port) to the SPS881  
Smart GPS antenna.  
2. Use the SCS900 software to output the corrections to the external SNB900  
radio-modem.  
3. Connect the HPB450 or TRIMMARK 3 radio to the Modem port of the SNB900  
radio-modem.  
4. From the front panel of the SNB900 radio-modem, set output to both Radio and  
Lemo.  
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A P P E N D I X  
E
Real-Time Data and Services  
E
In this appendix:  
The real-time Binary Output option (also known  
as RT17 messages or raw data) is available as an  
optional upgrade. The RT17 Streamed Data  
service is available only with the SPS751 Max and  
the SPS851 GPS receivers.  
By default, the Binary Output option is not  
enabled in the GPS receivers. The option must be  
enabled before RT17 messages can be streamed  
from the receiver. To enable the option, please  
contact your local Trimble dealer.  
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E
Real-Time Data and Services  
RT17 Streamed Data service  
An RT17 service provides GPS observations, ephemerides, and other information, as  
defined for that service. When a “client” connects to the service, all data flow is from  
the receiver to the client.  
Using the keypad and display to configure RT17 outputs  
You can configure RT17 output during the base and rover setup using the keypad and  
Using the web interface to configure RT17 outputs  
You can configure RT17 output using the I/O Configuration menu of the web interface  
of the receiver. Configure the stream to allow multiple client connections on a single  
port, or restrict the stream to a single client connection. To allow only authorized  
connections on the port, protect the output stream by requiring a password. See I/O  
Login authentication  
If you interface to the receivers using binary commands over serial communications,  
you may need login authentication. This has been added to most receiver models that  
run firmware version 3.30 or later.  
If your utilities such as the WinFlash utility or the Configuration ToolBox software do  
not work with the receivers running firmware version 3.30 or later, go to the Trimble  
website and then download the latest versions of these utilities. If your own application  
software no longer communicates with the receiver, please contact Trimble Support  
for information about how to use the receiver in these cases.  
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A P P E N D I X  
F
Upgrading the Receiver Firmware  
F
In this appendix:  
The GPS receiver is supplied with the latest  
version of the receiver firmware already installed.  
If a later version of the firmware becomes  
available, use the WinFlash utility to upgrade the  
firmware on your receiver.  
Q
Q
Q
You can also upgrade the receiver through the  
a web browser, page 77). If your receiver has  
access to the Internet, then whenever Trimble  
releases new firmware your receiver will check  
and display the new firmware version number in  
the Web browser. You can then decide to install  
the newer firmware from the Web browser.  
www.trimble.com/support.shtml and select the  
link to the receiver that you need updates for and  
then click Downloads.  
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F
Upgrading the Receiver Firmware  
The WinFlash utility  
The WinFlash utility communicates with Trimble products to perform various  
functions including:  
installing software, firmware, and option upgrades  
running diagnostics (for example, retrieving configuration information)  
configuring radios  
For more information, online help is also available when using the WinFlash utility.  
Note – The WinFlash utility runs on Microsoft Windows 95, 98, Windows NT®, 2000, Me,  
or XP operating systems.  
Installing the WinFlash utility  
You can install the WinFlash utility from the Trimble SPS GPS Receiver CD, or from the  
Trimble website.  
To install the WinFlash utility from the CD:  
1. Insert the disk into the CD drive on your computer.  
2. From the main menu select Install individual software packages.  
3. Select Install WinFlash.  
4. Follow the on-screen instructions.  
The WinFlash utility guides you through the firmware upgrade process, as described  
below. For more information, refer to the WinFlash Help.  
Upgrading the receiver firmware  
1. Start the WinFlash utility. The Device Configuration screen appears.  
2. From the Device type list, select your receiver.  
3. From the PC serial port field, select the serial (COM) port on the computer that  
the receiver is connected to.  
4. Click Next.  
The Operation Selection screen appears. The Operations list shows all of the  
supported operations for the selected device. A description of the selected  
operation is shown in the Description field.  
5. Select Load GPS software and then click Next.  
The GPS Software Selection window appears. This screen prompts you to select  
the software that you want to install on the receiver.  
6. From the Available Software list, select the latest version and then click Next.  
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Upgrading the Receiver Firmware  
F
The Settings Review window appears. This screen prompts you to connect the  
receiver, suggests a connection method, and then lists the receiver configuration  
and selected operation.  
7. If all is correct, click Finish.  
Based on the selections shown above, the Software Upgrade window appears and  
shows the status of the operation (for example, Establishing communication  
with <your receiver>. Please wait.).  
8. Click OK.  
The Software Upgrade window appears again and states that the operation was  
completed successfully.  
9. To select another operation, click Menu; to quit, click Exit.  
If you click Exit, the system prompts you to confirm.  
10. Click OK.  
Forcing the receiver into Monitor mode  
If the receiver will not go into Monitor mode to load new firmware, complete the  
following steps:  
1. Turn off the receiver.  
2. Press and hold F while turning on the receiver.  
3. Continue to hold the F button as the display shows the countdown timer.  
4. Once the display shows Remote Monitor Active:1, release the F button.  
5. The receiver is forced into Monitor mode and you can load the new firmware.  
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F
Upgrading the Receiver Firmware  
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A P P E N D I X  
G
Troubleshooting  
G
In this appendix:  
Use this appendix to identify and solve common  
problems that may occur with the receiver.  
Please read this section before you contact  
Technical Support.  
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G
Troubleshooting  
Receiver issues  
This section describes some possible receiver issues, possible causes, and how to solve  
them.  
Issue  
Possible cause  
Solution  
The receiver does External power is too  
Check the charge on the external battery and, if applicable,  
check the fuse.  
not turn on.  
low.  
Internal power is too  
low.  
Check the charge on the internal battery.  
External power is not  
properly connected.  
Check that the Lemo connector or 26-pin adaptor is seated  
correctly, and that the cable is secured to the receiver.  
Check for broken or bent pins in the connector.  
Faulty power cable.  
Check that you are using the correct cable for the  
port/battery.  
Check that the correct battery is connected to a particular  
port.  
The ports on the GPS receiver are optimized for use with  
different types of battery. The 26-pin connector is optimized  
for Trimble custom external batteries, and the Lemo port is  
optimized for external 12 V batteries such as car, motorcycle,  
or truck batteries. If the wrong type of battery is connected  
to a port, it is likely that it will cut off earlier than normal.  
Check pinouts with a multimeter to ensure internal wiring is  
intact.  
Receiver does not Insufficient memory.  
log data.  
Delete old files. Do one of the following:  
Press  
for 35 seconds.  
E
Use the delete and purge functions in the Data Logging  
menu of the web interface.  
Data Logging option is  
disabled.  
Order the Data Logging option from your local Trimble  
dealer. By default, data logging is disabled on all SPS GPS  
receivers. To see if data logging is enabled on your receiver,  
check your original purchase order or the receiver  
configuration using the web interface.  
The receiver is tracking  
fewer than four  
satellites.  
Wait until the receiver display shows that more than four  
satellites are being tracked.  
The internal memory  
needs to be reformatted  
Press  
for 35 seconds.  
Turn off the receiver and then turn it back on again.  
Press for 35 seconds.  
E
The receiver is not Receiver needs a soft  
responding.  
reset.  
Receiver needs a full  
reset.  
E
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Troubleshooting  
G
Issue  
Possible cause  
Solution  
The base station  
receiver is not  
broadcasting.  
Port settings between  
reference receiver and  
radio are incorrect.  
Using the SCS900 Site Controller software, connect to the  
reference radio through the receiver. If no connection is  
made, connect directly to the radio and change the port  
settings. Try to connect through the receiver again to ensure  
that they are communicating.  
Corrections are routed  
Check that corrections are routed correctly using the receiver  
to a port rather than to keypad and display.  
the internal radio  
modem.  
A rubber duck antenna is Check that the connections are made correctly and to the  
connected directly to the right connectors. Ensure that the connectors are seated  
radio antenna port on  
the receiver, or an  
external high-gain  
antenna is connected  
through a cable to the  
radio antenna port on  
the receiver.  
tightly and that there are no signs of damage to the cable.  
You are using AutoBase If you set up on a new point on a site that has not been  
and the AutoBase  
Warning function is  
enabled.  
occupied previously, the AutoBase Warning will prohibit the  
base station from broadcasting.  
Faulty cable between  
receiver and radio.  
Try a different cable.  
Examine the ports for missing pins.  
Use a multimeter to check pinouts.  
No power to radio.  
If the radio has its own power supply, check the charge and  
connections.  
Rover receiver is  
not receiving  
radio.  
The base station receiver See the issue,The base station receiver is not broadcasting.  
is not broadcasting.  
above.  
Incorrect over air baud  
Connect to the rover receiver radio, and make sure that it has  
rates between reference the same setting as the reference receiver.  
and rover.  
The SCS900 software automatically configures the over-the-  
air baud rate to 9600.  
Incorrect port settings  
If the radio is receiving data and the receiver is not getting  
between roving external radio communications, use the SCS900 software to check that  
radio and receiver. the port settings are correct.  
The radio antenna cable Make sure that the external radio antenna cable is connected  
and GPS antenna cable  
are not correctly  
connected.  
between the TNC connector marked RADIO and the radio  
antenna.  
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G
Troubleshooting  
Issue  
Possible cause  
Solution  
The receiver is not The GPS antenna is  
Make sure that the GPS antenna cable is tightly seated in the  
receiving satellite connected to the wrong GPS antenna connection on the receiver and not connected  
signals antenna connector. to the wrong/radio antenna connector.  
The GPS antenna cable is Make sure that the GPS antenna cable is tightly seated in the  
loose.  
GPS antenna connection on the GPS antenna.  
The cable is damaged.  
Check the cable for any signs of damage. A damaged cable  
can inhibit signal detection from the antenna at the receiver.  
The GPS antenna is not  
in clear line of sight to  
the sky.  
Make sure that the GPS antenna is located with a clear  
view of the sky.  
Restart the receiver as a last resort (turn off and then turn  
it on again).  
The message PC The WinFlash utility is in Complete the WinFlash task and then exit the utility.  
Loader in  
use.  
Control appears  
on the front panel  
The WinFlash utility was Plug the data cable back in and then restart the receiver.  
started then the data  
cable was disconnected.  
No apparent reason.  
If the WinFlash utility is not in use, turn off the receiver  
using the Power key.  
If that does not turn it off, apply external DC power and  
hold down the Power key for 60 seconds.  
The message  
Internet software  
If possible, turn off the receiver.  
Remote Monitor  
activeappears on  
the front panel  
If possible, reload the current firmware.  
If the above solutions do not resolve this, leave the  
receiver on with no external power, so the internal  
battery completely discharges. Then, turn on the receiver.  
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A P P E N D I X  
H
Drawings  
H
In this appendix:  
The drawings in this appendix show the  
dimensions of the receiver. Refer to these  
drawings if you need to build mounting brackets  
and housings for the receiver.  
The dimensions shown in these drawings are  
inches, with millimeters shown in brackets.  
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H
Drawings  
Back view  
Side view  
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Drawings  
H
Bottom view  
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H
Drawings  
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A P P E N D I X  
I
Receiver Connector Pinout  
Information  
I
In this appendix:  
The receivers have a wide range of interfacing  
options. There are a large number adaptors and  
cables available from Trimble that provide most  
of the common interfacing combinations.  
The receiver has two connectors:  
a zero shell 7-pin Lemo connector  
a high-density 26-pin D-sub connector  
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I
Receiver Connector Pinout Information  
Lemo connector  
The lemo connector is a 7-pin 0-shell Lemo connector.  
7
6
1
5
2
3
4
Pin  
1
Usage  
RS-232 Signal GND  
GND  
2
3
RS-232 TX data out  
CAN-  
4
5
CAN+  
6
DC Power In (+) 10.5-28 V DC  
RS-232 Serial data in  
7
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Receiver Connector Pinout Information  
I
Modem multi-function port  
Pin 1 is top left  
Pin 10 is middle left  
Pin 19 is bottom left  
Pin 9 is top right  
Pin 18 is middle right  
Pin 26 is bottom right  
Pin  
1
Usage  
RS-232 Modem port data terminal ready (DTR)  
RS-232 Modem port clear to send (CTS)  
RS-232 Modem port Data Set Ready (DSR)  
RS-232 Modem port Data Carrier Detect (DCD)  
RS-232 Modem port Ring Indicator (RI)  
GND  
2
3
4
5
6
7
RS-232 Modem port 2 Transmit Data (TX)  
RS-232 Modem port 2 Receive Data (RX)  
USB+  
8
9
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
26  
Ethernet Ground (ET_GND RJ45 Pin 4)  
RS-232 Modem port Ready to Send (TX)  
RS-232 Modem port Transmit Data (TX)  
Ethernet Ground (GND RJ45 Pin 5)  
Ethernet Ground (GND RJ45 Pin 8)  
USB ID  
Ethernet Receive Data+ (RD-RJ45 Pin 6)  
Ethernet Transmit Data+ (RD-RJ45 Pin 2)  
USB-  
USB Power  
1PPS  
RS-232 Modem Port Receive Data (RX)  
Ethernet Ground (GND RJ45 Pin 7)  
GND  
DC Power In 9–28 V DC  
Ethernet Receive Data+ (RD+, RJ45 Pin 3)  
Ethernet Transmit Data+ (TD+, RJ45 Pin 1)  
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I
Receiver Connector Pinout Information  
1PPS and ASCII time tag  
The SPSx51 receiver can output a 1 pulse-per-second (1PPS) time strobe and an  
associated time tag message. The time tags are output on a user-selected port.  
The leading edge of the pulse coincides with the beginning of each UTC second. The  
pulse is driven between nominal levels of 0.0 V and 5.0 V (see Figure I.1). The leading  
edge is positive (rising from 0 V to 5 V).  
Positive slope pulse  
5 V  
0 V  
Seconds  
Time tag output here  
Time tag applies here  
Figure I.1  
Time tag relation to 1PPS wave form  
The pulse is about 8 microseconds wide, with rise and fall times of about 100 nsec.  
Resolution is approximately 40 nsec, but the following external factor limits accuracy  
to approximately 1 microsecond:  
Antenna cable length  
Each meter of cable adds a delay of about 2 nsec to satellite signals, and a  
corresponding delay in the 1PPS pulse.  
1PPS is available on pin 20 on the back connector of the receiver. If you have  
applications that require 1PPS, Trimble recommends that you use cable P/N 60789-00  
because it has the following connectors:  
D9 port for modem 1/serial 2.  
D9 port for modem 2/serial 3. Pin 9 on this D9 port has 1PPS.  
BNC connector for 1PPS.  
Ethernet male plug for connection to receiver.  
USB plug.  
DC jack for supplying power to the receiver.  
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Receiver Connector Pinout Information  
I
ASCII time tag  
Each time tag is output about 0.5 second before the corresponding pulse. Time tags are  
in ASCII format on a user-selected serial port. The format of a time tag is:  
UTC yy.mm.dd hh:mm:ss ab  
Where:  
UTC is fixed text.  
yy.mm.dd is the year, month, and date.  
hh:mm:ss is the hour (on a 24-hour clock), minute, and second. The time is in  
UTC, not GPS.  
a is an integer number representing the position-fix type:  
1 = time only  
2 = 1D & time  
3 = currently unused  
4 = 2D & time  
5 = 3D & time  
b is the number of GPS satellites being tracked.  
Each time tag is terminated by a carriage return, line feed sequence. A typical  
printout looks like:  
UTC 02.12.21 20:21:16 56  
UTC 02.12.21 20:21:17 56  
UTC 02.12.21 20:21:18 56  
Note – If the receiver is not tracking satellites, the time tag is based on the receiver clock. In  
this case, a and b are represented by “??”. The time readings from the receiver clock are less  
accurate than time readings determined from the satellite signals.  
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I
Receiver Connector Pinout Information  
26-Pin D-sub connector wiring chart (P/N 60789-00)  
RJ45 plug  
USB A plug  
DE9-P plug  
DE9-S plug  
DC jack  
BNC plug  
DCD  
RX2  
TX2  
DTR  
GND  
DSR  
RTS  
CTS  
RI  
4
21  
12  
1
6
3
11  
2
5
1
2
3
4
5
6
7
8
9
DE9P  
(Serial 2)  
TX3  
RX3  
7
8
2
3
5
9
DE9S  
(Serial 3)  
1 PPS  
20  
CTR  
COND  
BNC  
SHELL  
TX+  
TX-  
RX+  
GND  
GND  
RX-  
GND  
GND  
26  
17  
25  
10  
13  
16  
22  
14  
1
2
3
4
5
6
7
8
RJ45 plug  
+5 V DC  
Data-  
Data+  
ID  
19  
18  
9
5
1
2
3
4
USB A plug (M)  
DC Jack  
POLE  
SHELL  
PWR  
GND  
24  
23  
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Glossary  
1PPS  
Pulse-per-second. Used in hardware timing. A pulse is generated in conjunction with a  
time stamp. This defines the instant when the time stamp is applicable.  
almanac  
A file that contains orbit information on all the satellites, clock corrections, and  
atmospheric delay parameters. The almanac is transmitted by a GPS satellite to a GPS  
receiver, where it facilitates rapid acquisition of GPS signals when you start collecting  
data, or when you have lost track of satellites and are trying to regain GPS signals.  
The orbit information is a subset of the emphemeris / ephemerides data.  
AutoBase  
AutoBase technology uses the position of the receiver to automatically select the  
correct base station; allowing for one button press operation of a base station. It  
shortens setup time associated with repeated daily base station setups at the same  
location on jobsites.  
base station  
Also called reference station. A base station in construction, is a receiver placed at a  
known point on a jobsite that tracks the same satellites as an RTK rover, and provides  
a real-time differential correction message stream through radio to the rover, to obtain  
centimeter level positions on a continuous real-time basis. A base station can also be a  
part of a virtual reference station network, or a location at which GPS observations are  
collected over a period of time, for subsequent postprocessing to obtain the most  
accurate position for the location.  
BINEX  
BInary EXchange format. BINEX is an operational binary format standard for  
GPS/GLONASS/SBAS research purposes. It has been designed to grow and allow  
encapsulation of all (or most) of the information currently allowed for in a range of  
other formats.  
broadcast server  
carrier  
An Internet server that manages authentication and password control for a network of  
VRS servers, and relays VRS corrections from the VRS server that you select.  
A radio wave having at least one characteristic (such as frequency, amplitude, or phase)  
that can be varied from a known reference value by modulation.  
carrier frequency  
The frequency of the unmodulated fundamental output of a radio transmitter. The GPS  
L1 carrier frequency is 1575.42 MHz.  
carrier phase  
Is the cumulative phase count of the GPS or GLONASS carrier signal at a given time.  
cellular modems  
A wireless adaptor that connects a laptop computer to a cellular phone system for data  
transfer. Cellular modems, which contain their own antennas, plug into a PC Card slot  
or into the USB port of the computer and are available for a variety of wireless data  
services such as GPRS.  
CMR  
Compact Measurement Record. A real-time message format developed by Trimble for  
broadcasting corrections to other Trimble receivers. CMR is a more efficient  
alternative to RTCM.  
CMR+  
covariance  
A statistical measure of the variance of two random variables that are observed or  
measured in the same mean time period. This measure is equal to the product of the  
deviations of corresponding values of the two variables from their respective means.  
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Glossary  
datum  
Also called geodetic datum. A mathematical model designed to best fit the geoid,  
defined by the relationship between an ellipsoid and, a point on the topographic  
surface, established as the origin of the datum. World geodetic datums are typically  
defined by the size and shape of an ellipsoid and the relationship between the center of  
the ellipsoid and the center of the earth.  
Because the earth is not a perfect ellipsoid, any single datum will provide a better  
model in some locations than in others. Therefore, various datums have been  
established to suit particular regions.  
For example, maps in Europe are often based on the European datum of 1950 (ED-50).  
Maps in the United States are often based on the North American datum of 1927  
(NAD-27) or 1983 (NAD-83).  
All GPS coordinates are based on the WGS-84 datum surface.  
deep discharge  
DGPS  
Withdrawal of all electrical energy to the end-point voltage before the cell or battery is  
recharged.  
differential  
correction  
Differential correction is the process of correcting GPS data collected on a rover with  
data collected simultaneously at a base station. Because the base station is on a known  
location, any errors in data collected at the base station can be measured, and the  
necessary corrections applied to the rover data.  
Differential correction can be done in real-time, or after the data has been collected by  
differential GPS  
DOP  
Dilution of Precision. A measure of the quality of GPS positions, based on the geometry  
of the satellites used to compute the positions. When satellites are widely spaced  
relative to each other, the DOP value is lower, and position accuracy is greater. When  
satellites are close together in the sky, the DOP is higher and GPS positions may  
contain a greater level of error.  
PDOP (Position DOP) indicates the three-dimensional geometry of the satellites. Other  
DOP values include HDOP (Horizontal DOP) and VDOP (Vertical DOP), which  
indicate the accuracy of horizontal measurements (latitude and longitude) and  
vertical measurements respectively. PDOP is related to HDOP and VDOP as follows:  
PDOP2 = HDOP2 + VDOP2  
dual-frequency GPS A type of receiver that uses both L1 and L2 signals from GPS satellites. A  
dual-frequency receiver can compute more precise position fixes over longer distances  
and under more adverse conditions because it compensates for ionospheric delays.  
EGNOS  
European Geostationary Navigation Overlay Service. A satellite-based augmentation  
system (SBAS) that provides a free-to-air differential correction service for GPS.  
EGNOS is the European equivalent of WAAS, which is available in the United States.  
elevation mask  
ellipsoid  
The angle below which the receiver will not track satellites. Normally set to 10 degrees  
to avoid interference problems caused by buildings and trees, atmospheric issues, and  
multipath errors.  
An ellipsoid is the three-dimensional shape that is used as the basis for mathematically  
modeling the earth’s surface. The ellipsoid is defined by the lengths of the minor and  
major axes. The earth’s minor axis is the polar axis and the major axis is the equatorial  
axis.  
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Glossary  
emphemeris /  
ephemerides  
A list of predicted (accurate) positions or locations of satellites as a function of time. A  
set of numerical parameters that can be used to determine a satellite’s position.  
Available as broadcast ephemeris or as postprocessed precise ephemeris.  
epoch  
The measurement interval of a GPS receiver. The epoch varies according to the  
measurement type: for real-time measurement it is set at one second; for  
postprocessed measurement it can be set to a rate of between one second and one  
minute. For example, if data is measured every 15 seconds, loading data using  
30-second epochs means loading every alternate measurement.  
feature  
A feature is a physical object or event that has a location in the real world, which you  
want to collect position and/or descriptive information (attributes) about. Features  
can be classified as surface or non-surface features, and again as points,  
lines/breaklines, or boundaries/areas.  
firmware  
GLONASS  
The program inside the receiver that controls receiver operations and hardware.  
Global Orbiting Navigation Satellite System. GLONASS is a Soviet space-based  
navigation system comparable to the American GPS system. The operational system  
consists of 21 operational and 3 non-operational satellites in 3 orbit planes.  
GNSS  
GSOF  
HDOP  
Global Navigation Satellite System.  
General Serial Output Format. A Trimble proprietary message format.  
Horizontal Dilution of Precision. HDOP is a DOP value that indicates the accuracy of  
horizontal measurements. Other DOP values include VDOP (vertical DOP) and PDOP  
(Position DOP).  
Using a maximum HDOP is ideal for situations where vertical precision is not  
particularly important, and your position yield would be decreased by the vertical  
component of the PDOP ( for example, if you are collecting data under canopy).  
L1  
L2  
The primary L-band carrier used by GPS and GLONASS satellites to transmit satellite  
data.  
The secondary L-band carrier used by GPS and GLONASS satellites to transmit  
satellite data.  
L2C  
L5  
A modernized code that allows significantly better ability to track the L2 frequency.  
The third L-band carrier used by GPS satellites to transmit satellite data. L5 will  
provide a higher power level than the other carriers. As a result, acquiring and tracking  
weak signals will be easier.  
Moving Base  
MSAS  
Moving Base is an RTK positioning technique in which both reference and rover  
receivers are mobile. Corrections are sent from a “base” receiver to a “rover” receiver  
and the resultant baseline (vector) has centimeter-level accuracy.  
MTSAT Satellite-Based Augmentation System. A satellite-based augmentation system  
(SBAS) that provides a free-to-air differential correction service for GPS. MSAS is the  
Japanese equivalent of WAAS, which is available in the United States.  
multipath  
Interference, similar to ghosts on an analog television screen, that occurs when GPS  
signals arrive at an antenna having traversed different paths. The signal traversing the  
longer path yields a larger pseudorange estimate and increases the error. Multiple  
paths can arise from reflections off the ground or off structures near the antenna.  
NMEA  
National Marine Electronics Association. NMEA 0183 defines the standard for  
interfacing marine electronic navigational devices. This standard defines a number of  
'strings' referred to as NMEA strings that contain navigational details such as positions.  
Most Trimble GPS receivers can output positions as NMEA strings.  
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Glossary  
OmniSTAR  
The OmniSTAR HP/XP service allows the use of new generation dual-frequency  
receivers with the OmniSTAR service. The HP/XP service does not rely on local  
reference stations for its signal, but utilizes a global satellite monitoring network.  
Additionally, while most current dual-frequency GPS systems are accurate to within a  
meter or so, OmniSTAR with XP is accurate in 3D to better than 30 cm.  
PDOP  
Position Dilution of Precision. PDOP is a DOP value that indicates the accuracy of  
three-dimensional measurements. Other DOP values include VDOP (vertical DOP) and  
HDOP (Horizontal Dilution of Precision).  
Using a maximum PDOP value is ideal for situations where both vertical and  
horizontal precision are important.  
postprocessing  
Postprocessing is the processing of satellite data after it has been collected, in order to  
eliminate error. This involves using computer software to compare data from the rover  
with data collected at the base station.  
real-time differential Also known as real-time differential correction or DGPS. Real-time differential GPS is the  
GPS  
process of correcting GPS data as you collect it. Corrections are calculated at a base  
station and then sent to the receiver through a radio link. As the rover receives the  
position it applies the corrections to give you a very accurate position in the field.  
Most real-time differential correction methods apply corrections to code phase  
positions.  
While DGPS is a generic term, its common interpretation is that it entails the use of  
single-frequency code phase data sent from a GPS base station to a rover GPS receiver  
to provide sub-meter position accuracy. The rover receiver can be at a long range  
(greater than 100 kms (62 miles)) from the base station.  
rover  
A rover is any mobile GPS receiver that is used to collect or update data in the field,  
typically at an unknown location.  
Roving mode  
RTCM  
Roving mode applies to the use of a rover receiver to collect data, stakeout, or control  
earthmoving machinery in real time using RTK techniques.  
Radio Technical Commission for Maritime Services. A commission established to  
define a differential data link for the real-time differential correction of roving GPS  
receivers. There are three versions of RTCM correction messages. All Trimble GPS  
receivers use Version 2 protocol for single-frequency DGPS type corrections. Carrier  
phase corrections are available on Version 2, or on the newer Version 3 RTCM protocol,  
which is available on certain Trimble dual-frequency receivers. The Version 3 RTCM  
protocol is more compact but is not as widely supported as Version 2.  
RTK  
real-time kinematic. A real-time differential GPS method that uses carrier phase  
measurements for greater accuracy.  
SBAS  
Satellite-Based Augmentation System. SBAS is based on differential GPS, but applies to  
wide area (WAAS/EGNOS and MSAS) networks of reference stations. Corrections and  
additional information are broadcast via geostationary satellites.  
signal-to-noise ratio SNR. The signal strength of a satellite is a measure of the information content of the  
signal, relative to the signal’s noise. The typical SNR of a satellite at 30° elevation is  
between 47 and 50 dBHz.  
skyplot  
The satellite skyplot confirms reception of a differentially corrected GPS signal and  
displays the number of satellites tracked by the GPS receiver, as well as their relative  
positions.  
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Glossary  
SNR  
triple frequency GPS A type of receiver that uses three carrier phase measurements (L1, L2, and L5).  
UTC  
VRS  
Universal Time Coordinated. A time standard based on local solar mean time at the  
Greenwich meridian.  
Virtual Reference Station. A VRS system consists of GPS hardware, software, and  
communication links. It uses data from a network of base stations to provide  
corrections to each rover that are more accurate than corrections from a single base  
station.  
To start using VRS corrections, the rover sends its position to the VRS server. The VRS  
server uses the base station data to model systematic errors (such as ionospheric  
noise) at the rover position. It then sends RTCM correction messages back to the rover.  
WAAS  
Wide Area Augmentation System. WAAS was established by the Federal Aviation  
Administration (FAA) for flight and approach navigation for civil aviation. WAAS  
improves the accuracy and availability of the basic GPS signals over its coverage area,  
which includes the continental United States and outlying parts of Canada and  
Mexico.  
The WAAS system provides correction data for visible satellites. Corrections are  
computed from ground station observations and then uploaded to two geostationary  
satellites. This data is then broadcast on the L1 frequency, and is tracked using a  
channel on the GPS receiver, exactly like a GPS satellite.  
Use WAAS when other correction sources are unavailable, to obtain greater accuracy  
than autonomous positions. For more information on WAAS, refer to the FAA website  
The EGNOS service is the European equivalent and MSAS is the Japanese equivalent of  
WAAS.  
WGS-84  
World Geodetic System 1984. Since January 1987, WGS-84 has superseded WGS-72 as  
the datum used by GPS.  
The WGS-84 datum is based on the ellipsoid of the same name.  
SPSx51 Modular GPS Receivers User Guide 183  
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Glossary  
184 SPSx51 Modular GPS Receivers User Guide  
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NORTH AMERICA  
EUROPE  
ASIA - PACIFIC  
Trimble Construction Division  
5475 Kellenburger Road  
Dayton, Ohio 45424  
usA  
800-538-7800 (Toll Free)  
+1-937-245-5600 Phone  
+1-937-233-9004 Fax  
Trimble GmbH  
Trimble Navigation Australia  
PTY Limited  
Am Prime Parc 11  
65479 Raunheim  
gerMANY  
+49-6142-2100-0 Phone  
+49-6142-2100-550 Fax  
Level 1/120 Wickham Street  
Fortitude Valley, QLD 4006  
AusTrALiA  
+61-7-3216-0044 Phone  
+61-7-3216-0088 Fax  
www.trimble.com  
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