Garmin GPS Receiver 18X User Manual

GPS 18x  
TECHNICAL  
SPECIFICATIONS  
Garmin International, Inc.  
1200 E. 151st Street  
Olathe, KS 66062 USA  
190-00879-08 Revision D  
October 2011  
Download from Www.Somanuals.com. All Manuals Search And Download.  
TABLE OF CONTENTS  
1 Introduction..............................................................................................................................1  
1.1 Cautions...........................................................................................................................................................1  
1.2 Limited Warranty ............................................................................................................................................2  
1.3 Overview.........................................................................................................................................................3  
1.4 Features ...........................................................................................................................................................3  
1.5 GPS 18x Series................................................................................................................................................4  
1.5.1  
1.5.2  
1.5.3  
GPS 18x USB.................................................................................................................................................... 4  
GPS 18x PC ...................................................................................................................................................... 4  
GPS 18x LVC, GPS 18x LVC-5m, and GPS 18x-5Hz ..................................................................................... 4  
1.6 Technical Specifications..................................................................................................................................5  
1.6.1  
Physical Characteristics..................................................................................................................................... 5  
1.6.1.1 Size.................................................................................................................................................... 5  
1.6.1.2 Weight............................................................................................................................................... 5  
1.6.1.3 Color.................................................................................................................................................. 5  
1.6.1.4 Case Material..................................................................................................................................... 5  
1.6.1.5 Cable Length ..................................................................................................................................... 5  
Electrical Characteristics................................................................................................................................... 5  
1.6.2.1 Input Voltage..................................................................................................................................... 5  
1.6.2.2 Input Current ..................................................................................................................................... 5  
1.6.2.3 CMOS Serial Output Levels.............................................................................................................. 5  
1.6.2.4 GPS Receiver Sensitivity .................................................................................................................. 5  
1.6.2.5 Environmental Characteristics........................................................................................................... 6  
GPS Performance.............................................................................................................................................. 6  
1.6.3.1 Receiver............................................................................................................................................. 6  
1.6.3.2 Acquisition Times ............................................................................................................................. 6  
1.6.3.3 Update Rate....................................................................................................................................... 6  
1.6.3.4 Accuracy ........................................................................................................................................... 6  
Interfaces........................................................................................................................................................... 6  
1.6.4.1 GPS 18x Electrical Characteristics.................................................................................................... 6  
1.6.4.2 Garmin Interface and Garmin USB Protocol..................................................................................... 6  
1.6.4.3 GPS 18x PC, GPS 18x LVC, & GPS 18x-5Hz Protocols.................................................................. 7  
1.6.4.4 Measurement Pulse Output (GPS 18x LVC & GPS 18x-5Hz only).................................................. 7  
1.6.2  
1.6.3  
1.6.4  
2 GPSx 18x LVC & GPS 18x -5Hz Wiring and Pinouts .........................................................8  
2.1 GPS 18x LVC & GPS 18x -5Hz Pinout..........................................................................................................8  
2.2 GPS 18x LVC & GPS 18x -5Hz Wiring Diagrams.........................................................................................8  
3 Mechanical Characteristics & Mounting.............................................................................10  
4 GPS 18x PC, GPS 18x LVC, & GPS 18x-5Hz Software Interface....................................12  
4.1 Received NMEA 0183 Sentences .................................................................................................................12  
4.1.1  
4.1.2  
4.1.3  
4.1.4  
4.1.5  
Almanac Information (ALM).......................................................................................................................... 12  
Sensor Initialization Information (PGRMI) .................................................................................................... 13  
Sensor Configuration Information (PGRMC) ................................................................................................. 13  
Additional Sensor Configuration Information (PGRMC1) ............................................................................. 14  
Output Sentence Enable/Disable (PGRMO) ................................................................................................... 14  
4.2 Transmitted NMEA 0183 Sentences.............................................................................................................15  
4.2.1  
4.2.2  
4.2.3  
4.2.4  
4.2.5  
4.2.6  
4.2.7  
Sentence Transmission Rate............................................................................................................................ 15  
Transmitted Time............................................................................................................................................ 16  
Global Positioning System Almanac Data (ALM).......................................................................................... 16  
Global Positioning System Fix Data (GGA) ................................................................................................... 17  
GPS DOP and Active Satellites (GSA)........................................................................................................... 17  
GPS Satellites in View (GSV)......................................................................................................................... 17  
Recommended Minimum Specific GPS/TRANSIT Data (RMC) ................................................................... 18  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page iii  
Download from Www.Somanuals.com. All Manuals Search And Download.  
4.2.8  
4.2.9  
Track Made Good and Ground Speed (VTG) ................................................................................................. 18  
Geographic Position (GLL)............................................................................................................................. 18  
4.2.10 Estimated Error Information (PGRME) .......................................................................................................... 18  
4.2.11 GPS Fix Data Sentence (PGRMF) .................................................................................................................. 19  
4.2.12 Programmable Device ID (PGRMID)............................................................................................................. 19  
4.2.13 Map Datum (PGRMM)................................................................................................................................... 19  
4.2.14 Sensor Status Information (PGRMT).............................................................................................................. 19  
4.2.15 3D Velocity Information (PGRMV) ............................................................................................................... 20  
4.2.16 DGPS Beacon Information (PGRMB) ............................................................................................................ 20  
4.3 Baud Rate Selection ......................................................................................................................................20  
4.4 Measurement Pulse Output (GPS 18x LVC & 18x-5Hz only)......................................................................20  
4.4.1  
4.4.2  
One-Pulse-Per-Second (PPS) Output (GPS 18x LVC Only)........................................................................... 20  
Five-Pulse-Per-Second Output (GPS 18x-5Hz Only) ..................................................................................... 20  
Appendix A: Earth Datum List ..................................................................................................22  
Appendix B: Garmin Binary Output Format ...........................................................................25  
Appendix C: Changing the Baud Rate in Garmin Mode.........................................................29  
Appendix D: GPS 18x PC/ LVC/18x-5Hz & Windows Serial Mouse Issue ...........................30  
Appendix E: Sensor Configuration Software............................................................................32  
Downloading the Sensor Configuration Software........................................................................................................... 32  
Selecting a Model ........................................................................................................................................................... 32  
Connecting to the Sensor ................................................................................................................................................ 32  
Menus 33  
File Menu........................................................................................................................................................................ 33  
Comm Menu ................................................................................................................................................................... 33  
Config Menu................................................................................................................................................................... 33  
View Menu ..................................................................................................................................................................... 34  
Help Menu ...................................................................................................................................................................... 34  
LIST OF TABLES AND FIGURES  
Table 1: GPS 18x LVC & GPS 18x-5Hz Wire Pinout ..................................................................................................8  
Figure 1: Computer Serial Port Interconnection............................................................................................................8  
Figure 2. PDA Serial Port Interconnection....................................................................................................................9  
Figure 3. Basic NMEA Device Interconnection............................................................................................................9  
Figure 4a. GPS 18x Bottom Case Dimensions, Under Mold.......................................................................................10  
Figure 4b. GPS 18x Bottom Case, Outside of Casing .................................................................................................10  
Figure 5. GPS 18x Suction Cup Mount Center Hole Dimensions...............................................................................11  
Figure 6. GPS 18x Flush Mount Dimensions..............................................................................................................11  
Figure 7. GPS 18x Flush Mount Center Hole Dimensions..........................................................................................11  
Table 2: NMEA 0183 Output Sentence Order and Size ..............................................................................................15  
Table 3: Characters per Second for Available Baud Rates..........................................................................................15  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page iv  
Download from Www.Somanuals.com. All Manuals Search And Download.  
1
INTRODUCTION  
1.1 CAUTIONS  
CAUTION  
The GPS system is operated by the government of the United States, which is solely responsible for its accuracy and  
maintenance. Although the GPS 18x is a precision electronic NAVigation AID (NAVAID), any NAVAID can be  
misused or misinterpreted, and therefore become unsafe. Use these products at your own risk. To reduce the risk,  
carefully review and understand all aspects of these Technical Specifications before using the GPS 18x. When in  
actual use, carefully compare indications from the GPS to all available navigation sources including the information  
from other NAVAIDs, visual sightings, charts, etc. For safety, always resolve any discrepancies before continuing  
navigation.  
FCC  
Compliance  
This device complies with part 15 of the FCC Rules. 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.  
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. 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 may cause  
harmful interference to radio communications if not installed and used in accordance with the instructions. 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 of the following measures:  
Reorient or relocate the receiving antenna.  
Increase the separation between the equipment and the receiver.  
Connect the equipment into an outlet that is on a different circuit from the GPS unit.  
Consult the dealer or an experienced radio/TV technician for help.  
This product does not contain any user-serviceable parts. Repairs should only be made by an authorized Garmin  
service center. Unauthorized repairs or modifications could result in permanent damage to the equipment, and void  
your warranty and your authority to operate this device under Part 15 regulations.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 1  
Download from Www.Somanuals.com. All Manuals Search And Download.  
1.2 LIMITED WARRANTY  
This Garmin product is warranted to be free from defects in materials or workmanship for one year from the date of  
purchase. Within this period, Garmin will, at its sole option, repair or replace any components that fail in normal  
use. Such repairs or replacement will be made at no charge to the customer for parts or labor, provided that the  
customer shall be responsible for any transportation cost. This warranty does not apply to: (i) cosmetic damage, such  
as scratches, nicks and dents; (ii) consumable parts, such as batteries, unless product damage has occurred due to a  
defect in materials or workmanship; (iii) damage caused by accident, abuse, misuse, water, flood, fire, or other acts  
of nature or external causes; (iv) damage caused by service performed by anyone who is not an authorized service  
provider of Garmin; or (v) damage to a product that has been modified or altered without the written permission of  
Garmin. In addition, Garmin reserves the right to refuse warranty claims against products or services that are  
obtained and/or used in contravention of the laws of any country.  
This product is intended to be used only as a travel aid and must not be used for any purpose requiring precise  
measurement of direction, distance, location or topography. Garmin makes no warranty as to the accuracy or  
completeness of map data in this product.  
THE WARRANTIES AND REMEDIES CONTAINED HEREIN ARE EXCLUSIVE AND IN LIEU OF ALL  
OTHER WARRANTIES EXPRESS, IMPLIED, OR STATUTORY, INCLUDING ANY LIABILITY ARISING  
UNDER ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE,  
STATUTORY OR OTHERWISE. THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, WHICH MAY  
VARY FROM STATE TO STATE.  
IN NO EVENT SHALL GARMIN BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT OR  
CONSEQUENTIAL DAMAGES, INCLUDING, WITHOUT LIMITATION, DAMAGES FOR ANY TRAFFIC  
FINES OR CITATIONS, WHETHER RESULTING FROM THE USE, MISUSE OR INABILITY TO USE THE  
PRODUCT OR FROM DEFECTS IN THE PRODUCT. SOME STATES DO NOT ALLOW THE EXCLUSION  
OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATIONS MAY NOT APPLY  
TO YOU.  
Garmin retains the exclusive right to repair or replace (with a new or newly-overhauled replacement product) the  
device or software or offer a full refund of the purchase price at its sole discretion. SUCH REMEDY SHALL BE  
YOUR SOLE AND EXCLUSIVE REMEDY FOR ANY BREACH OF WARRANTY.  
To obtain warranty service, contact your local Garmin authorized dealer or call Garmin Product Support for  
shipping instructions and an RMA tracking number. Securely pack the device and a copy of the original sales  
receipt, which is required as the proof of purchase for warranty repairs. Write the tracking number clearly on the  
outside of the package. Send the device, freight charges prepaid, to any Garmin warranty service station.  
Online Auction Purchases: Products purchased through online auctions are not eligible for warranty coverage.  
Online auction confirmations are not accepted for warranty verification. To obtain warranty service, an original or  
copy of the sales receipt from the original retailer is required. Garmin will not replace missing components from any  
package purchased through an online auction.  
International Purchases: A separate warranty may be provided by international distributors for devices purchased  
outside the United States depending on the country. If applicable, this warranty is provided by the local in-country  
distributor and this distributor provides local service for your device. Distributor warranties are only valid in the area  
of intended distribution. Devices purchased in the United States or Canada must be returned to the Garmin service  
center in the United Kingdom, the United States, Canada, or Taiwan for service.  
Garmin’s Marine Warranty Policy: Certain Garmin Marine products in certain areas have a longer warranty  
period and additional terms and conditions. Go to www.garmin.com/support/warranty.html for more details and to  
see if your product is covered under Garmin’s Marine Warranty Policy.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 2  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
1.3 OVERVIEW  
The GPS 18x series products include an embedded receiver and an antenna. Based on the proven technology found  
in other Garmin GPS receivers, the GPS 18x tracks multiple satellites at a time while providing fast time-to-first-fix,  
precise navigation updates (five times per second for the GPS 18x-5Hz, and once per second for the GPS 18x USB,  
18x PC, and 18x LVC), and low power consumption. This generation of GPS sensors includes the capability of FAA  
Wide Area Augmentation System (WAAS) differential GPS.  
The GPS 18x design uses the latest technology and high-level circuit integration to achieve superior performance  
while minimizing space and power requirements. The hardware capability combined with software intelligence  
makes the GPS 18x easy to integrate and use.  
The GPS 18x series products are designed to withstand rugged operating conditions and are waterproof to IEC  
60529 IPX7, immersion in 1 meter of water for 30 minutes. These complete GPS receivers require minimal  
additional components to be supplied by an OEM or system integrator. A minimum system must provide the GPS  
with a source of power and a clear view of the GPS satellites. Internal FLASH memory allows the GPS to retain  
critical data such as satellite orbital parameters, last-known position, date and time. End user interfaces such as  
keyboards and displays are the responsibility of the application designer.  
1.4 FEATURES  
GPS receiver tracks and uses multiple satellites for fast, accurate positioning and velocity estimates.  
Differential DGPS capability using real-time WAAS corrections yielding position accuracy of less than 3  
meters.  
Compact, rugged design ideal for applications with minimal space.  
Factory configuration meets the needs of most systems that expect NMEA 0183 data from a GPS receiver.  
Configuration commands are available to customize the NMEA 0183 output (see section 4.1 Received  
(GPS 18x LVC and GPS 18x-5Hz only) Highly accurate measurement pulse output for precise timing  
measurements: one-pulse-per-second (1 Hz) for the GPS 18x LVC or 5 Hz for GPS 18x-5Hz. Pulse width  
is configurable in 20-millisecond increments from 20 ms to 980 ms with 1 µs accuracy.  
Configurable for binary format data output.  
FLASH-based program allows new software revisions through a Web site download.  
Non-volatile memory does not require battery backup.  
Onboard rechargeable backup battery can maintain the real-time clock for up to 10 days.  
Configurable parameters include expected position, current time and date, and preferred position fix type  
(3D or automatic).  
Waterproof design allows continuous exposure to the prevailing weather conditions at most locations.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 3  
Download from Www.Somanuals.com. All Manuals Search And Download.  
1.5 GPS 18x SERIES  
There are several different versions of GPS 18x available. Refer below for a list of the three major divisions of the  
GPS 18x Series.  
1.5.1 GPS 18x USB  
The GPS 18x USB interfaces to a computer with an available USB port. Drivers  
are available for use on Windows computers. Macintosh and Linux drivers are  
not available from Garmin. After the drivers are loaded, the device appears to the  
Windows operating system as a USB-connected device and appears in Device  
Manager as a Garmin USB Device.  
1.5.2 GPS 18x PC  
The GPS 18x PC interfaces to a serial port of a computer via a DB-9  
connector and receives power through a 12-volt cigarette lighter adapter.  
The unit accepts TIA-232-F (RS-232) level inputs and transmits voltage  
levels that swing from zero V (ground) to 5 V TIA-232-F (RS-232)  
polarity.  
The GPS 18x PC can cause an issue with Windows operating systems if  
the DB9 connector is plugged into the computer before the navigation  
software is up and running. The Windows operating system may  
interpret the serial connector on the GPS 18x as a serial mouse. Please  
1.5.3 GPS 18x LVC, GPS 18x LVC-5m, and GPS 18x-5Hz  
These products interface to a serial port. The units accept TIA-232-F (RS-232) level inputs and transmit voltage  
levels that swing from ground to the positive supply voltage, TIA-232-F (RS-232) polarity. They also have reverse  
polarity protection. The cable contains wires for power, ground, receive, transmit, and measurement pulse output.  
At the end of the cable, the wires are terminated in a connector that is used  
by Garmin for testing purposes. Most customers will remove this  
connector and replace it with another connector of their own choosing.  
Removing the factory installed connector and/or replacing with another  
customer-supplied connector will have no affect on the warranty (see  
section 1.2 Limited Warranty). The factory-installed connector will mate  
with JST right-angle PCB-mount connector (model BM06B-SRSS-TBT)  
or side-entry PCB-mount connector (model SM06B-SRSS-TB). You may  
obtain technical information on these PCB-mount mating connectors from  
the JST Web site: www.jst.com.  
Note: Unless otherwise specified, all references to the GPS 18x LVC also include the GPS 18x LVC-5m.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 4  
Download from Www.Somanuals.com. All Manuals Search And Download.  
1.6 TECHNICAL SPECIFICATIONS  
Specifications are subject to change without notice.  
1.6.1 Physical Characteristics  
1.6.1.1 Size  
61 mm (2.4 inches) in diameter and 19.5 mm (0.77 inches) in height  
1.6.1.2 Weight  
GPS 18x USB:  
3.7 oz (105 g)  
6.3 oz (180 g)  
GPS 18x PC:  
GPS 18x LVC-5m (5 meter cable): 5.6 oz (160 g)  
GPS 18x-5Hz (5 meter cable): 5.8 oz (165 g)  
1.6.1.3 Color  
Black  
1.6.1.4 Case Material  
Polycarbonate thermoplastic that is waterproof to IEC 60529 IPX7 level (immersion in 1 meter of water for 30  
minutes)  
1.6.1.5 Cable Length  
GPS 18x USB: 2 meter  
GPS 18x PC: 2 meter  
GPS 18x LVC: 5 meter (Garmin Part Number 010-00321-36)  
GPS 18x-5Hz: 5 meter  
1.6.2 Electrical Characteristics  
1.6.2.1 Input Voltage  
GPS 18x USB: 4.4–5.5 Vdc  
GPS 18x PC:  
8–30 Vdc (Automotive supply from cigarette lighter jack)  
GPS 18x LVC: 4.0–5.5 Vdc  
GPS 18x-5Hz: 4.0–5.5 Vdc  
1.6.2.2 Input Current  
GPS 18x USB: 110 mA @ 5.0 Vdc  
GPS 18x PC: 65 mA @ 12 Vdc  
GPS 18x LVC: 90 mA @ 5.0 Vdc  
GPS 18x-5Hz: 100 mA @ 5.0 Vdc  
1.6.2.3 CMOS Serial Output Levels  
GPS 18x PC:  
0 Vdc to 5 Vdc (Asynchronous Serial, TIA-232-F (RS-232) Compatible Polarity)  
GPS 18x LVC and GPS 18x-5Hz: 0 Vdc to Vin, between 4 and 5.5 Vdc (Asynchronous Serial, TIA-232-F  
(RS-232) Compatible Polarity)  
1.6.2.4 GPS Receiver Sensitivity  
-185 dBW minimum  
190-00879-08  
GPS 18x Technical Specifications  
Page 5  
Rev. D  
Download from Www.Somanuals.com. All Manuals Search And Download.  
1.6.2.5 Environmental Characteristics  
Operating Temperature: -30°C to +80°C (-22°F to +176°F)  
Storage Temperature: -40°C to +90°C (-40°F to +194°F)  
1.6.3 GPS Performance  
1.6.3.1 Receiver  
WAAS-enabled GPS receiver continuously tracks and uses multiple satellites to compute and update your position.  
1.6.3.2 Acquisition Times  
Reacquisition: Less than 2 seconds  
Hot:  
Approx. 1 second (all data known)  
Warm:  
Cold:  
Approx. 38 seconds (initial position, time, and almanac known; ephemeris unknown)  
Approx. 45 seconds  
1.6.3.3 Update Rate  
GPS 18x USB, PC, and LVC:  
1 record per second  
5 records per second  
GPS 18x-5Hz:  
1.6.3.4 Accuracy  
GPS Standard Positioning Service (SPS)  
Position:  
Velocity:  
< 15 meters, 95% typical  
0.1 knot RMS steady state  
WAAS  
Position:  
Velocity:  
< 3 meters, 95% typical  
0.1 knot RMS steady state  
Measurement Pulse Output Time: ±1 microsecond at rising edge of the pulse  
Dynamics: 999 knots velocity (only limited at altitude greater than 60,000 feet), 2g dynamics  
1.6.4 Interfaces  
1.6.4.1 GPS 18x Electrical Characteristics  
GPS 18x USB: USB 2.0 full-speed protocol compatible, as well as USB 1.1 full-speed protocol.  
GPS 18x PC and LVC: TIA-232-F (RS-232) compatible asynchronous receiver. Default setting is 4800  
baud.  
GPS 18x-5Hz: TIA-232-F (RS-232) compatible asynchronous receiver. Default setting is 19200 baud.  
1.6.4.2 Garmin Interface and Garmin USB Protocol  
Refer to the Garmin Device Interface Specification found in the Garmin Device Interface SDK for information  
about the Garmin Interface and the Garmin USB Protocol. At the time of this printing, this document is located on  
See Appendix B: Garmin Binary Output Format for additional information concerning access to binary data from  
the GPS 18x USB.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 6  
Download from Www.Somanuals.com. All Manuals Search And Download.  
1.6.4.3 GPS 18x PC, GPS 18x LVC, & GPS 18x-5Hz Protocols  
NMEA 0183 Version 2.0 or NMEA 0183 Version 2.30 (Version 2.0 is factory default, programmable by  
data field 7 of the PGRMC1 sentence described in section 4.1.4 Additional Sensor Configuration  
Available NMEA 0183 output sentences include GPALM, GPGGA, GPGSA, GPGSV, GPRMC, GPVTG,  
GPGLL, PGRME, PGRMF, PGRMID, PGRMM, PGRMT, PGRMV, and PGRMB (Garmin proprietary  
sentences). See section 4.2 Transmitted NMEA 0183 Sentences for format descriptions.  
Configuration and initialization is accomplished with NMEA 0183 input sentences. Allows initialization of  
information such as expected position, date, time, earth datum, and differential mode. See section 4.1  
Received NMEA 0183 Sentences for format descriptions.  
Configurable for binary data output.  
1.6.4.4 Measurement Pulse Output (GPS 18x LVC & GPS 18x-5Hz only)  
GPS 18x LVC: 1 Hz pulse with programmable width, configurable in 20 ms increments form 20 ms to 980  
ms. See section 4.1.3 Sensor Configuration Information (PGRMC) for details about configuring the  
Measurement Pulse Output (or PPS) feature.  
GPS 18x-5Hz: 5 Hz pulse synchronized with the time of fix. One of the five pulses will align with the UTC  
second boundary. The pulse width is programmable from 20 ms to 180 ms. The PGRMC sentence will  
indicate which pulse is at the top-of-the-second. See section 4.1.3 Sensor Configuration Information  
(PGRMC) for details about configuring the Measurement Pulse Output (or PPS) feature.  
1 µs accuracy for all conditions in which the GPS 18x LVC or GPS 18x-5Hz has reported a valid and  
accurate position fix for at least the previous 4 seconds.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 7  
Download from Www.Somanuals.com. All Manuals Search And Download.  
2
GPSX 18x LVC & GPS 18x -5Hz WIRING AND PINOUTS  
The GPS 18x LVC/18x-5Hz interfaces to a serial port. The unit accepts TIA-232-F (RS-232) level inputs and  
transmits voltage levels from ground to the input voltage, TIA-232-F (RS-232) polarity.  
The GPS 18x LVC/18x-5Hz wires are terminated with a six-wire connector that is used by Garmin for testing  
purposes. You can remove this connector without voiding your warranty (see section 1.2 Limited Warranty).  
2.1 GPS 18x LVC & GPS 18x -5Hz PINOUT  
GPS 18x Pin  
Color  
Signal Name  
Wire Gauge  
#
1
2
3
4
5
6
Yellow  
Red  
Black  
White  
Black  
Green  
Measurement Pulse Output  
Vin  
28  
26  
28  
28  
26  
28  
Ground  
Transmit Data  
Ground  
Receive Data  
Table 1: GPS 18x LVC & GPS 18x-5Hz Wire Pinout  
2.2 GPS 18x LVC & GPS 18x -5Hz WIRING DIAGRAMS  
Figure 1: Computer Serial Port Interconnection  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 8  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Figure 2. PDA Serial Port Interconnection  
Figure 3. Basic NMEA Device Interconnection  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 9  
Download from Www.Somanuals.com. All Manuals Search And Download.  
3
MECHANICAL CHARACTERISTICS & MOUNTING  
The central threaded recess accepts a metric M3 threaded bolt. The recess is approximately 4 mm deep (4.32 +/-  
0.08 mm). The following drawings show example geometries for mounting hardware in case you wish to design  
your own custom mount. Figure 5 shows mounting geometry for a mount formed from steel sheet metal that is 1.15  
mm thick. Figure 7 shows similar mounting geometry for mount formed from aluminum sheet metal that is 1.25 mm  
thick. Use caution when tightening the mounting bolt. Tightening the mounting bolt can cause the mount to pull  
tight directly against the metal insert, not against the plastic housing, which would tend to pull the insert out of the  
plastic. Figure 6 shows the dimensions of our GPS 18x Flush Mount, part number 010-10453-00.  
Figure 4a. GPS 18x Bottom Case Dimensions, Under Mold  
UNITS: MILLIMETERS  
Figure 4b. GPS 18x Bottom Case, Outside of Casing  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 10  
Download from Www.Somanuals.com. All Manuals Search And Download.  
UNITS: MILLIMETERS  
Figure 5. GPS 18x Suction Cup Mount Center Hole Dimensions  
UNITS: MILLIMETERS  
Figure 6. GPS 18x Flush Mount Dimensions  
Figure 7. GPS 18x Flush Mount Center Hole Dimensions  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 11  
Download from Www.Somanuals.com. All Manuals Search And Download.  
4
GPS 18x PC, GPS 18x LVC, & GPS 18x-5Hz SOFTWARE INTERFACE  
The interface protocol design of the GPS 18x PC, LVC, and GPS 18x-5Hz products is based on the National Marine  
Electronics Association’s NMEA 0183 ASCII interface specification. This standard is fully defined in NMEA 0183,  
Version 2.30. Copies may be obtained from NMEA at www.nmea.org.  
In addition to the standard NMEA 0183 sentences, the GPS 18x PC, LVC, and GPS 18x-5Hz may also be  
configured to transmit information over their serial interface using NMEA 0183 compliant Garmin proprietary  
sentences. These proprietary sentences begin with the characters, “$PGRM”, instead of the characters “$G” that are  
typical of the standard NMEA 0183 sentences. The characters “$P” indicate that the sentence is a proprietary  
implementation and the characters and “GRM” indicate that it is Garmin’s proprietary sentence. The letter (or  
letters) that follow the characters “$PGRM” uniquely identifies that particular Garmin proprietary sentence.  
It is also possible to configure the GPS 18x PC, LVC, and GPS 18x-5Hz to transmit binary data information over  
their serial interface. See Appendix B: Garmin Binary Output Format for details.  
The GPS 18x USB does not transmit NMEA sentences: It transmits using the Garmin USB interface. The Garmin  
USB interface is discussed in the Garmin Device Interface Specification found in the Garmin Device Interface SDK  
located on the Garmin Web site at: www.garmin.com/support/commProtocol.html.  
You can configure the GPS 18x USB to transmit binary data information over the USB interface. Refer to Appendix  
The following sections describe the NMEA 0183 data format of each sentence transmitted and received by the GPS  
18x PC, LVC, and GPS 18x-5Hz products.  
4.1 RECEIVED NMEA 0183 SENTENCES  
The following paragraphs define the sentences that can be received on the GPS sensors’ port. Null fields in the  
configuration sentence indicate no change in the particular configuration parameter. All sentences received by the  
GPS sensor must be terminated with <CR><LF>, the ASCII characters for carriage return (0D hexadecimal) and  
line feed (0A hexadecimal). The checksum *hh is used for parity checking data and is not required, but is  
recommended for use in environments containing high electromagnetic noise. It is generally not required in normal  
PC environments. When used, the parity bytes (hh) are the ASCII representation of the exclusive-or (XOR) sum of  
all the characters between the “$” and “*” characters, non-inclusive. The hex representation must be a capital letter,  
such as 3D instead of 3d. Sentences may be truncated by <CR><LF> after any data field and valid fields up to that  
point will be acted on by the sensor.  
4.1.1 Almanac Information (ALM)  
The $GPALM sentence can be used to initialize the GPS sensor’s stored almanac information in the unlikely event  
of non-volatile memory loss or after storing longer than six months without tracking GPS satellites.  
$GPALM,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>,<15>*hh<CR><LF>  
<1>  
<2>  
Total number of ALM sentences to be transmitted by the GPS sensor during almanac download.  
This field can be null or any number when sending almanac to the GPS sensor.  
Number of current ALM sentence. This field can be null or any number when sending almanac  
to the GPS sensor.  
<3>  
<4>  
<5>  
<6>  
<7>  
<8>  
<9>  
Satellite PRN number, 01 to 32  
GPS week number  
SV health, bits 17–24 of each almanac page  
Eccentricity  
Almanac reference time  
Inclination angle  
Rate of right ascension  
<10> Root of semi major axis  
<11> Omega, argument of perigee  
<12> Longitude of ascension node  
<13> Mean anomaly  
<14> af0 clock parameter  
<15> af1 clock parameter  
190-00879-08  
GPS 18x Technical Specifications  
Page 12  
Rev. D  
Download from Www.Somanuals.com. All Manuals Search And Download.  
     
4.1.2 Sensor Initialization Information (PGRMI)  
The $PGRMI sentence provides information used to initialize the GPS sensor’s set position and time used for  
satellite acquisition. Receipt of this sentence by the GPS sensor causes the software to restart the satellite acquisition  
process. If there are no errors in the sentence, it will be echoed upon receipt. If an error is detected, the echoed  
PGRMI sentence will contain the current default values. Current PGRMI defaults (with the exception of the  
Receiver Command, which is a command rather than a mode) can also be obtained by sending $PGRMIE to the  
GPS sensor.  
$PGRMI,<1>,<2>,<3>,<4>,<5>,<6>,<7>*hh<CR><LF>  
<1>  
Latitude, ddmm.mmm format for GPS 18x PC/LVC; ddmm.mmmmm format for GPS 18x-  
5Hz (leading zeros must be transmitted)  
<2>  
<3>  
Latitude hemisphere, N or S  
Longitude, ddmm.mmm format for GPS 18x PC/LVC; ddmm.mmmmm format for GPS  
18x-5Hz (leading zeros must be transmitted)  
<4>  
<5>  
<6>  
Longitude hemisphere, E or W  
Current UTC date, ddmmyy format  
Current UTC time, hhmmss format for GPS 18x PC/LVC; hhmmss.s format for GPS 18x-  
5Hz  
<7>  
Receiver Command, A = Cold Start, R = Unit Reset  
4.1.3 Sensor Configuration Information (PGRMC)  
The $PGRMC sentence provides information used to configure the GPS sensor’s operation. Configuration  
parameters are stored in non-volatile memory and retained between power cycles. The GPS sensor will echo this  
sentence upon its receipt if no errors are detected. If an error is detected, the echoed PGRMC sentence will contain  
the current default values. Current default values can also be obtained by sending $PGRMCE to the GPS sensor.  
$PGRMC,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>*hh<CR><LF>  
<1>  
<2>  
<3>  
Fix mode, A = Automatic, 3 = 3D exclusively  
Altitude above/below mean sea level, -1500.0 to 18000.0 meters  
Earth datum index. If the user datum index (96) is specified, fields <4> through <8> must contain  
valid values. Otherwise, fields <4> through <8> must be null. Refer to Appendix A: Earth Datum List  
for a list of earth datum and the corresponding earth datum index.  
<4>  
<5>  
<6>  
<7>  
<8>  
<9>  
User earth datum semi-major axis, 6360000.000 to 6380000.000 meters (.001 meters resolution)  
User earth datum inverse flattening factor, 285.0 to 310.0 (10-9 resolution)  
User earth datum delta x earth centered coordinate, -5000.0 to 5000.0 meters (1 meter resolution)  
User earth datum delta y earth centered coordinate, -5000.0 to 5000.0 meters (1 meter resolution)  
User earth datum delta z earth centered coordinate, -5000.0 to 5000.0 meters (1 meter resolution)  
Differential mode, A = Automatic (output DGPS data when available, non-DGPS otherwise), D =  
Differential exclusively (output only differential fixes)  
<10>  
<11>  
<12>  
<13>  
NMEA 0183 Baud rate, 3 = 4800, 4 = 9600, 5 = 19200, 8 = 38400 (for GPS 18x-5Hz only)  
No Effect (This field is not used on this model and is included only for backwards compatibility)  
Measurement Pulse Output, 1 = Disabled, 2 = Enabled  
Measurement Pulse Output pulse length, (n+1)*20 ms  
For 18 LVC/PC n = 0 through 48 (max. 980 ms)  
For GPS 18x-5Hz n = 0 through 8 (max. 180 ms)  
Example: n = 4 corresponds to a 100 ms wide pulse  
<14>  
Dead reckoning valid time 1 to 30 sec. for the GPS 18x PC/LVC  
or 0.2 to 30.0 sec. for the GPS 18x-5Hz  
All configuration changes take effect after receipt of a valid value except baud rate and Measurement Pulse Output  
mode. Baud rate and Measurement Pulse Output mode changes take effect on the next power cycle or an external  
reset event.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 13  
Download from Www.Somanuals.com. All Manuals Search And Download.  
   
4.1.4 Additional Sensor Configuration Information (PGRMC1)  
The $PGRMC1 sentence provides additional information used to configure the GPS sensor operation. Configuration  
parameters are stored in non-volatile memory and retained between power cycles. The GPS sensor will echo this  
sentence upon its receipt if no errors are detected. If an error is detected, the echoed PGRMC1 sentence will contain  
the current default values. Current default values can also be obtained by sending $PGRMC1E to the GPS sensor.  
$PGRMC1,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>,<15>*hh<CR><LF>  
<1>  
NMEA 0183 output time 1 to 900 (sec). Not applicable to GPS 18x-5Hz, which always outputs data at  
5 Hz (200 ms)  
<2>  
<3>  
<4>  
<5>  
<6>  
<7>  
<8>  
<9>  
Binary Output Data, 1 = Off, 2 = On.  
No Effect (This field is not used on this model and is included only for backwards compatibility)  
No Effect (DGPS beacon frequency: 0.0, 283.5 to 325.0 kHz in 0.5 kHz steps)  
No Effect (DGPS beacon bit rate: 0, 25, 50, 100, or 200 bps)  
No Effect (DGPS beacon scanning, 1 = Off, 2 = On)  
NMEA 0183 version 2.30 mode indicator, 1 = Off, 2 = On  
DGPS WAAS mode, W = WAAS Enabled, N = WAAS Disabled  
Power Save Mode, P = Power Save mode, N = Normal  
<10> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<11> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<12> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<13> Measurement Pulse Output Auto Off Mode, 1 = Off, 2 = On  
<14> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<15> Low Velocity Threshold , 1 = Off, 2 = On  
Configuration changes take effect immediately, with the exception of Binary Output Data, which takes effect on the  
next power cycle or a reset event. Send the sentence “$PGRMI,,,,,,,R” to command a reset (refer to section 4.1.2  
Sensor Initialization Information (PGRMI)). If the GPS sensor is in the Binary data mode, it is necessary to send the  
following eight-byte data stream to temporarily change the data format to NMEA 0183. Then follow by sending a  
PGRMC1 sentence that turns off the Binary Output Data format:  
10 0A 02 26 00 CE 10 03 (Hexadecimal)  
4.1.5 Output Sentence Enable/Disable (PGRMO)  
The $PGRMO sentence provides the ability to enable and disable specific output sentences. The following sentences  
are enabled at the factory for the GPS 18x PC and LVC: GPGGA, GPGSA, GPGSV, GPRMC, and PGRMT.  
The following sentences are enabled at the factory for the GPS 18x-5Hz: GPGGA, GPGSA, GPRMC, GPVTG, and  
PGRMT.  
$PGRMO,<1>,<2>*hh<CR><LF>  
<1>  
<2>  
Target sentence description (for example, PGRMT, GPGSV, etc.)  
Target sentence mode, where 0 = Disable specified sentence, 1 = enable specified sentence, 2 =  
Disable all output sentences, 3 = Enable all output sentences (except GPALM), 4 = Restore factory  
default output sentences  
The following notes apply to the PGRMO input sentence:  
If the target sentence mode is “2” (Disable all), “3” (Enable all), or ‘4’ (Restore defaults), the target sentence  
description is not checked for validity. In this case, an empty field is allowed (for example, $PGRMO,,3), or the  
mode field may contain from 1 to 5 characters.  
If the target sentence mode is “0” (Disable) or “1” (Enable), the target sentence description field must be an  
identifier for one of the sentences that can be output by the GPS sensor.  
If either the target sentence mode field or the target sentence description field is not valid, the PGRMO sentence will  
have no effect.  
$PGRMO,GPALM,1 will cause the GPS sensor to transmit all stored almanac information. All other NMEA 0183  
sentence transmission will be suspended temporarily.  
$PGRMO,,G will cause the COM port to change to Garmin Data Transfer format for the duration of the power  
cycle. The Garmin mode is required for GPS 18x series product software updates.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 14  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
4.2 TRANSMITTED NMEA 0183 SENTENCES  
The subsequent paragraphs define the sentences that can be transmitted by the GPS 18x PC and LVC.  
4.2.1 Sentence Transmission Rate  
Sentences are transmitted with respect to the user selected baud rate.  
The GPS sensor will transmit each sentence (except where noted in particular transmitted sentence descriptions) at a  
periodic rate based on the user selected baud rate and user selected output sentences. The GPS sensor will transmit  
the selected sentences contiguously. The length of the transmission can be determined by the following equation and  
Tables 2 and 3:  
total characters to be transmitted  
length of transmission  
=
---------------------------------------------  
characters transmitted per second  
Sentence  
Output by Default?  
Maximum Characters  
GPRMC  
GPGGA  
GPGSA  
GPGSV  
PGRME  
GPGLL  
GPVTG  
PGRMV  
PGRMF  
PGRMB  
PGRMID  
PGRMM  
PGRMT  
74  
82  
66  
70  
35  
44  
42  
32  
82  
40  
82  
(PC and LVC only)  
(18x-5Hz)  
Once per minute  
50  
Table 2: NMEA 0183 Output Sentence Order and Size  
Baud  
4800  
Characters per Second  
480  
960  
9600  
19200  
38400  
1920  
3840  
Table 3: Characters per Second for Available Baud Rates  
The maximum number of fields allowed in a single sentence is 82 characters including delimiters. Values in the  
table include the sentence start delimiter character “$” and the termination delimiter <CR><LF>. For the GPS 18x  
PC and LVC, the factory set defaults result in a once per second transmission at the NMEA 0183 specification  
transmission rate of 4800 baud. For the GPS 18x-5Hz, the factory set defaults will result in a five times per second  
transmission at 19200 baud.  
For the GPS 18x LVC: Regardless of the selected baud rate, the information transmitted by the GPS sensor is  
referenced to the one-pulse-per-second output pulse immediately preceding the GPRMC sentence, or whichever  
sentence is output first in the burst (see Table 2 above).  
For the GPS 18x-5Hz: Regardless of the selected baud rate, the information transmitted by the GPS sensor is  
referenced to the preceding five-times-per-second output pulse.  
The GPS 18x USB can use Spanner (an application that can provide NMEA output via a virtual COM port) to  
receive the same default NMEA sentences as the GPS 18x PC and LVC at a rate of once per second. Spanner is  
available for free on the Garmin web site. To download the software, start at www.garmin.com/oem, select the GPS  
18x USB, and then select Updates & Downloads.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 15  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
4.2.2 Transmitted Time  
The GPS sensor outputs Coordinated Universal Time (UTC) date and time of day in the transmitted sentences.  
Before the initial position fix, the on-board clock provides the date and time of day. After the initial position fix, the  
date and time of day are calculated using GPS satellite information and are synchronized with the measurement  
pulse output.  
The GPS 18x-5Hz outputs a UTC with a tenths-of-a-second precision: 123456.8, for example.  
The GPS sensor uses information obtained from the GPS satellites to add or delete UTC leap seconds and correct the  
transmitted date and time of day. The transmitted date and time of day for leap second correction follow the  
guidelines in “National Institute of Standards and Technology Special Publication 432 (Revised 1990)” (for sale by  
the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C., 20402, U.S.A.).  
When a positive leap second is required, one second is inserted at the beginning of the first hour (0h 0m 0s) of the  
day that the positive leap is occurring. The minute containing the leap second is 61 seconds long. The GPS sensor  
would have transmitted this information for the leap second added December 31, 1998 as follows:  
$GPRMC,235959,A,3851.3651,N,09447.9382,W,000.0,221.9,071103,003.3,E*69  
$GPRMC,000000,A,3851.3651,N,09447.9382,W,000.0,221.9,081103,003.3,E*67  
$GPRMC,000000,A,3851.3651,N,09447.9382,W,000.0,221.9,081103,003.3,E*67  
$GPRMC,000001,A,3851.3651,N,09447.9382,W,000.0,221.9,081103,003.3,E*66  
If a negative leap second should be required, one second will be deleted at the end of some UTC month. The minute  
containing the leap second will be only 59 seconds long. In this case, the GPS sensor will not transmit the time of  
day 0h 0m 0s (the “zero” second) for the day from which the leap second is removed.  
$GPRMC,235959,A,3851.3650,N,09447.9373,W,000.0,000.0,111103,003.3,E*69  
$GPRMC,000001,A,3851.3650,N,09447.9373,W,000.0,000.0,121103,003.3,E*6A  
$GPRMC,000002,A,3851.3650,N,09447.9373,W,000.0,000.0,121103,003.3,E*69  
4.2.3 Global Positioning System Almanac Data (ALM)  
Almanac sentences are not normally transmitted. Send the GPS sensor a $PGRMO,GPALM,1 command to initiate  
almanac transmission. Upon receipt of this command, the GPS sensor will transmit available almanac information  
on GPALM sentences. During the transmission of almanac sentences, other NMEA 0183 data output is suspended  
temporarily.  
$GPALM,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>,<15>*hh<CR><LF>  
<field information> can be found in section 4.1.1 Almanac Information (ALM).  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 16  
Download from Www.Somanuals.com. All Manuals Search And Download.  
4.2.4 Global Positioning System Fix Data (GGA)  
$GPGGA,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,M,<10>,M,<11>,<12>*hh<CR><LF>  
<1>  
<2>  
UTC time of position fix, hhmmss format for GPS 18x PC or LVC; hhmmss.s format for GPS  
18x-5Hz  
Latitude, ddmm.mmmm format for GPS 18x PC/LVC; ddmm.mmmmm for GPS 18x-5Hz  
(leading zeros will be transmitted)  
<3>  
<4>  
Latitude hemisphere, N or S  
Longitude, dddmm.mmmm format for GPS 18x PC/LVC; dddmm.mmmmm for GPS 18x-5Hz  
(leading zeros will be transmitted)  
<5>  
<6>  
Longitude hemisphere, E or W  
GPS quality indication, 0 = fix not available, 1 = Non-differential GPS fix available, 2 =  
Differential GPS (WAAS) fix available, 6 = Estimated  
<7>  
<8>  
<9>  
Number of satellites in use, 00 to 12 (leading zeros will be transmitted)  
Horizontal dilution of precision, 0.5 to 99.9  
Antenna height above/below mean sea level, -9999.9 to 99999.9 meters  
<10> Geoidal height, -999.9 to 9999.9 meters  
<11> Null (Differential GPS)  
<12> Null (Differential Reference Station ID)  
4.2.5 GPS DOP and Active Satellites (GSA)  
$GPGSA,<1>,<2>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<4>,<5>,<6>*hh<CR><LF>  
<1>  
<2>  
<3>  
Mode, M = Manual, A = Automatic  
Fix type, 1 = not available, 2 = 2D, 3 = 3D  
PRN number, 01 to 32, of satellite used in solution, up to 12 transmitted (leading zeros will be  
transmitted)  
<4>  
<5>  
<6>  
Position dilution of precision, 0.5 to 99.9  
Horizontal dilution of precision, 0.5 to 99.9  
Vertical dilution of precision, 0.5 to 99.9  
4.2.6 GPS Satellites in View (GSV)  
$GPGSV,<1>,<2>,<3>,<4>,<5>,<6>,<7>,...<4>,<5>,<6>,<7>*hh<CR><LF>  
<1>  
<2>  
<3>  
<4>  
<5>  
<6>  
<7>  
Total number of GSV sentences to be transmitted  
Number of current GSV sentence  
Total number of satellites in view, 00 to 12 (leading zeros will be transmitted)  
Satellite PRN number, 01 to 32 (leading zeros will be transmitted)  
Satellite elevation, 00 to 90 degrees (leading zeros will be transmitted)  
Satellite azimuth, 000 to 359 degrees, true (leading zeros will be transmitted)  
Signal to noise ratio (C/No) 00 to 99 dB (leading zeros will be transmitted)  
Note: Items <4>,<5>,<6>, and <7> repeat for each satellite in view to a maximum of four (4) satellites per sentence.  
Additional satellites in view information must be sent in subsequent bursts of NMEA 0183 data. These fields will be  
null if unused.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 17  
Download from Www.Somanuals.com. All Manuals Search And Download.  
4.2.7 Recommended Minimum Specific GPS/TRANSIT Data (RMC)  
$GPRMC,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>*hh<CR><LF>  
<1>  
UTC time of position fix, hhmmss format for GPS 18x PC/LVC;  
hhmmss.s format for GPS 18x-5Hz  
<2>  
<3>  
Status, A = Valid position, V = NAV receiver warning  
Latitude, ddmm.mmmm format for GPS 18x PC/LVC; ddmm.mmmmm format for GPS 18x-  
5Hz (leading zeros must be transmitted)  
<4>  
<5>  
Latitude hemisphere, N or S  
Longitude, dddmm.mmmm format for GPS 18x PC/LVC; dddmm.mmmmm format for GPS  
18x-5Hz (leading zeros must be transmitted)  
<6>  
<7>  
Longitude hemisphere, E or W  
Speed over ground, GPS 18x PC and LVC: 000.0 to 999.9 knots, GPS 18x-5Hz: 000.00 to  
999.99 knots (leading zeros will be transmitted)  
<8>  
<9>  
Course over ground, 000.0 to 359.9 degrees, true (leading zeros will be transmitted)  
UTC date of position fix, ddmmyy format  
<10> Magnetic variation, 000.0 to 180.0 degrees (leading zeros will be transmitted)  
<11> Magnetic variation direction, E or W (westerly variation adds to true course)  
<12> Mode indicator (only output if NMEA 0183 version 2.30 active), A = Autonomous,  
D = Differential, E = Estimated, N = Data not valid  
4.2.8 Track Made Good and Ground Speed (VTG)  
$GPVTG,<1>,T,<2>,M,<3>,N,<4>,K,<5>*hh<CR><LF>  
<1>  
<2>  
<3>  
<4>  
<5>  
True course over ground, GPS 18x PC and LVC: 000 to 359 degrees, GPS 18x-5Hz: 000.0 to  
359.9 degrees(leading zeros will be transmitted)  
Magnetic course over ground, 000 to 359 degrees, GPS 18x-5Hz: 000.0 to 359.9  
degrees(leading zeros will be transmitted)  
Speed over ground, GPS 18x PC and LVC: 000.0 to 999.9 knots, GPS 18x-5Hz: 000.00 to  
999.99 knots (leading zeros will be transmitted)  
Speed over ground, GPS 18x PC and LVC: 0000.0 to 1851.8 kilometers per hour, GPS 18x-  
5Hz: 0000.00 to 1851.89 (leading zeros will be transmitted)  
Mode indicator (only output if NMEA 0183 version 2.30 active), A = Autonomous,  
D = Differential, E = Estimated, N = Data not valid  
4.2.9 Geographic Position (GLL)  
$GPGLL,<1>,<2>,<3>,<4>,<5>,<6>,<7>*hh<CR><LF>  
<1>  
Latitude, ddmm.mmmm format for GPS 18x PC/LVC; ddmm.mmmmm format for GPS 18x-  
5Hz (leading zeros must be transmitted)  
<2>  
<3>  
Latitude hemisphere, N or S  
Longitude, dddmm.mmmm format for GPS 18x PC/LVC; dddmm.mmmmm format for GPS  
18x-5Hz (leading zeros must be transmitted)  
<4>  
<5>  
Longitude hemisphere, E or W  
UTC time of position fix, hhmmss format for GPS 18x PC/LVC; hhmmss.s format for GPS  
18x-5Hz  
<6>  
<7>  
Status, A = Valid position, V = NAV receiver warning  
Mode indicator (only output if NMEA 0183 version 2.30 active), A = Autonomous,  
D = Differential (WAAS), E = Estimated, N = Data not valid  
4.2.10 Estimated Error Information (PGRME)  
$PGRME,<1>,M,<2>,M,<3>,M*hh<CR><LF>  
<1>  
<2>  
<3>  
Estimated horizontal position error (HPE), 0.0 to 999.9 meters  
Estimated vertical position error (VPE), 0.0 to 999.9 meters  
Estimated position error (EPE), 0.0 to 999.9 meters  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 18  
Download from Www.Somanuals.com. All Manuals Search And Download.  
4.2.11 GPS Fix Data Sentence (PGRMF)  
$PGRMF,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>,<15>*hh<CR><LF>  
<1>  
<2>  
<3>  
<4>  
GPS week number (0 to 1023)  
GPS seconds (0 to 604799)  
UTC date of position fix, ddmmyy format  
UTC time of position fix, hhmmss format for GPS 18x PC/LVC; hhmmss.s format for GPS  
18x-5Hz  
<5>  
<6>  
GPS leap second count  
Latitude, ddmm.mmmm format for GPS 18x PC/LVC; ddmm.mmmmm format for GPS 18x-  
5Hz (leading zeros must be transmitted)  
<7>  
<8>  
Latitude hemisphere, N or S  
Longitude, dddmm.mmmm format for GPS 18x PC/LVC; dddmm.mmmmm format for GPS  
18x-5Hz (leading zeros must be transmitted)  
<9>  
Longitude hemisphere, E or W  
<10> Mode, M = Manual, A = Automatic  
<11> Fix type, 0 = no fix, 1 = 2D fix, 2 = 3D fix  
<12> Speed over ground, 0 to 1851 kilometers/hour  
<13> Course over ground, 0 to 359 degrees, true  
<14> Position dilution of precision, 0 to 9 (rounded to nearest integer value)  
<15> Time dilution of precision, 0 to 9 (rounded to nearest integer value)  
4.2.12 Programmable Device ID (PGRMID)  
The Garmin Proprietary sentence $PGRMID gives the device owner the flexibility of naming each sensor device  
with a custom text value.  
$PGRMID,<1>,<2>,<3>*hh<CR><LF>  
<1>  
<2>  
<3>  
ID Configuration Command, S = Set ID, C = Clear ID, E = Echo ID  
User Defined ID (Maximum number of characters = 58)  
Garmin Unit ID (Predefined and unique to each device)  
4.2.13 Map Datum (PGRMM)  
The Garmin Proprietary sentence $PGRMM gives the name of the map datum currently in use by the GPS sensor.  
This information is used by the Garmin MapSource real-time plotting application.  
$PGRMM,<1>*hh<CR><LF>  
<1> Name of map datum currently in use (variable length field, for example, “WGS 84”)  
4.2.14 Sensor Status Information (PGRMT)  
The Garmin Proprietary sentence $PGRMT gives information concerning the status of the GPS sensor. This  
sentence is transmitted once per minute regardless of the selected baud rate.  
$PGRMT,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>*hh<CR><LF>  
<1> Product, model and software version (variable length field, for example, “GPS 18x VER 2.05”)  
<2> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<3> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<4> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<5> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<6> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<7> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<8> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<9> No Effect (This field is not used on this model and is included only for backwards compatibility)  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 19  
Download from Www.Somanuals.com. All Manuals Search And Download.  
4.2.15 3D Velocity Information (PGRMV)  
$PGRMV,<1>,<2>,<3>*hh<CR><LF>  
<1> True east velocity, -514.4 to 514.4 meters/second for GPS 18x PC/LVC; -514.44 to 514.44 for GPS  
18x-5Hz  
<2> True north velocity, -514.4 to 514.4 meters/second for GPS 18x PC/LVC; -514.44 to 514.44 for GPS  
18x-5Hz  
<3> Up velocity, -999.9 to 999.9 meters/second for GPS 18x PC/LVC; -999.99 to 999.99 for GPS 18x-5Hz  
4.2.16 DGPS Beacon Information (PGRMB)  
Note: The GPS 18x products do not support PGRMB at this time.  
$PGRMB,<1>,<2>,<3>,<4>,<5>,K,<6>,<7>,<8>*hh<CR><LF>  
<1> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<2> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<3> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<4> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<5> Distance to beacon reference station in kilometers  
<6> No Effect (This field is not used on this model and is included only for backwards compatibility)  
<7> DGPS fix source (R = RTCM, W = WAAS, N = Non-DGPS Fix)  
<8> DGPS mode, A = Automatic, W = WAAS Only, R = RTCM Only, N = None (DGPS disabled)  
4.3 BAUD RATE SELECTION  
Baud rate selection can be performed by sending the appropriate configuration sentence to the GPS sensor as  
4.4 MEASUREMENT PULSE OUTPUT (GPS 18x LVC & 18x-5Hz ONLY)  
4.4.1 One-Pulse-Per-Second (PPS) Output (GPS 18x LVC Only)  
The highly accurate one-pulse-per-second (PPS) output is provided for applications requiring precise timing  
measurements. After the initial position fix has been calculated, the PPS signal is generated and continues until the  
unit is powered down. The rising edge of the signal is aligned to the start of each GPS second within 1 µs for all  
conditions in which the re ceiver has reported a valid and accurate position for at least the previous 4 seconds.  
The NMEA 0183 sentences that follow each rising edge of the PPS signal tell when you were and where you were at  
that previous rising edge of the PPS signal, beginning with the GPRMC sentence as the lead sentence in any  
particular NMEA 0183 record.  
Regardless of the selected baud rate, the information transmitted by the GPS 18x series products is referenced to the  
pulse immediately preceding the NMEA 0183 RMC sentence.  
The accuracy of the one-pulse-per-second output is maintained only while the GPS receiver is computing a valid  
position fix. To obtain the most accurate results, the one-pulse-per-second output should be calibrated against a local  
time reference to compensate for cable and internal receiver delays and the local time bias.  
The default pulse width is 100 ms, however; it may be programmed in 20 ms increments between 20 ms and 980 ms  
4.4.2 Five-Pulse-Per-Second Output (GPS 18x-5Hz Only)  
The highly accurate five-pulse-per-second output is provided for applications requiring precise timing  
measurements. After the initial position fix has been calculated, the GPS 18x-5Hz generates the pulse signal, which  
continues until power down. The rising edge of the signal is aligned to the start of each GPS second within 1 µs for  
all conditions in which the receiver has reported a valid and accurate position for at least the previous 4 seconds.  
The NMEA 0183 sentences that follow each rising edge of the Measurement Pulse Output signal tell when and  
where you were at that previous rising edge of the Measurement Pulse Output signal, beginning with the GPRMC  
sentence as the lead sentence in any particular NMEA 0183 record.  
Regardless of the selected baud rate, the information transmitted by the GPS 18x-5Hz is referenced to the preceding  
five times per-second output pulse.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 20  
Download from Www.Somanuals.com. All Manuals Search And Download.  
The accuracy of the five-pulse-per-second output is maintained only while the GPS 18x-5Hz can compute a valid  
position fix. To obtain the most accurate results, the five-pulse-per-second output should be calibrated against a  
local time reference to compensate for cable and internal receiver delays and the local time bias.  
The default pulse width is 100 ms, however; it may be programmed in 20 ms increments between 20 ms and 180 ms  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 21  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
APPENDIX A: EARTH DATUM LIST  
The following is a list of the Garmin GPS 18x Earth datum indices and the corresponding earth datum name  
(including the area of application):  
0
ADINDAN–Ethiopia, Mali, Senegal, Sudan  
AUSTRALIAN GEODETIC 1984–Australia, Tasmania Island  
ASTRO DOS 71/4–St. Helena Island  
ASTRONOMIC STATION 1952–Marcus Island  
ASTRO B4 SOROL ATOLL–Tern Island  
BELLEVUE (IGN)–Efate and Erromango Islands  
BERMUDA 1957–Bermuda Islands  
9
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
25  
26  
27  
BOGOTA OBSERVATORY–Colombia  
CAMPO INCHAUSPE–Argentina  
CANTON ASTRO 1966–Phoenix Islands  
CAPE CANAVERAL–Florida, Bahama Islands  
CAPE–South Africa  
CARTHAGE–Tunisia  
CHATHAM 1971–Chatham Island (New Zealand)  
CHUA ASTRO–Paraguay  
CORREGO ALEGRE–Brazil  
DJAKARTA (BATAVIA)–Sumatra Island (Indonesia)  
DOS 1968–Gizo Island (New Georgia Islands)  
EASTER ISLAND 1967–Easter Island  
EUROPEAN 1950–Austria, Belgium, Denmark, Finland, France, Germany, Gibraltar, Greece, Italy,  
Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland  
28  
29  
30  
31  
32  
EUROPEAN 1979–Austria, Finland, Netherlands, Norway, Spain, Sweden, Switzerland  
FINLAND HAYFORD 1910–Finland  
GANDAJIKA BASE–Republic of Maldives  
GEODETIC DATUM 1949–New Zealand  
ORDNANCE SURVEY OF GREAT BRITAIN 1936–England, Isle of Man, Scotland, Shetland Islands,  
Wales  
33  
34  
35  
36  
37  
38  
39  
40  
41  
42  
43  
GUAM 1963–Guam Island  
GUX 1 ASTRO–Guadalcanal Island  
HJORSEY 1955–Iceland  
HONG KONG 1963–Hong Kong  
INDIAN–Bangladesh, India, Nepal  
INDIAN–Thailand, Vietnam  
IRELAND 1965–Ireland  
ISTS O73 ASTRO 1969–Diego Garcia  
JOHNSTON ISLAND 1961–Johnston Island  
KANDAWALA–Sri Lanka  
KERGUELEN ISLAND–Kerguelen Island  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 22  
Download from Www.Somanuals.com. All Manuals Search And Download.  
44  
45  
46  
47  
48  
49  
50  
51  
52  
53  
54  
55  
56  
57  
KERTAU 1948–West Malaysia, Singapore  
L.C. 5 ASTRO–Cayman Brac Island  
LIBERIA 1964–Liberia  
LUZON–Mindanao Island  
LUZON–Phillippines (excluding Mindanao Island)  
MAHE 1971–Mahe Island  
MARCO ASTRO–Salvage Islands  
MASSAWA–Eritrea (Ethiopia)  
MERCHICH–Morocco  
MIDWAY ASTRO 1961–Midway Island  
MINNA–Nigeria  
NORTH AMERICAN 1927–Alaska  
NORTH AMERICAN 1927–Bahamas (excluding San Salvador Island)  
NORTH AMERICAN 1927–Central America (Belize, Costa Rica, El Salvador, Guatemala, Honduras,  
Nicaragua)  
58  
59  
60  
NORTH AMERICAN 1927–Canal Zone  
NORTH AMERICAN 1927–Canada (including Newfoundland Island)  
NORTH AMERICAN 1927–Caribbean (Barbados, Caicos Islands, Cuba, Dominican Republic, Grand  
Cayman, Jamaica, Leeward Islands, Turks Islands)  
61  
62  
63  
64  
65  
66  
67  
68  
69  
70  
71  
72  
73  
74  
75  
76  
77  
78  
79  
80  
81  
82  
NORTH AMERICAN 1927–Mean Value (CONUS)  
NORTH AMERICAN 1927–Cuba  
NORTH AMERICAN 1927–Greenland (Hayes Peninsula)  
NORTH AMERICAN 1927–Mexico  
NORTH AMERICAN 1927–San Salvador Island  
NORTH AMERICAN 1983–Alaska, Canada, Central America, CONUS, Mexico  
NAPARIMA, BWI–Trinidad and Tobago  
NAHRWAN–Masirah Island (Oman)  
NAHRWAN–Saudi Arabia  
NAHRWAN–United Arab Emirates  
OBSERVATORIO 1966–Corvo and Flores Islands (Azores)  
OLD EGYPTIAN–Egypt  
OLD HAWAIIAN–Mean Value  
OMAN–Oman  
PICO DE LAS NIEVES–Canary Islands  
PITCAIRN ASTRO 1967–Pitcairn Island  
PUERTO RICO–Puerto Rico, Virgin Islands  
QATAR NATIONAL–Qatar  
QORNOQ–South Greenland  
REUNION–Mascarene Island  
ROME 1940–Sardinia Island  
RT 90–Sweden  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 23  
Download from Www.Somanuals.com. All Manuals Search And Download.  
83  
84  
PROVISIONAL SOUTH AMERICAN 1956–Bolivia, Chile, Colombia, Ecuador, Guyana, Peru, Venezuela  
SOUTH AMERICAN 1969–Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Guyana, Paraguay,  
Peru, Venezuela, Trinidad and Tobago  
85  
SOUTH ASIA–Singapore  
86  
PROVISIONAL SOUTH CHILEAN 1963–South Chile  
SANTO (DOS)–Espirito Santo Island  
SAO BRAZ–Sao Miguel, Santa Maria Islands (Azores)  
SAPPER HILL 1943–East Falkland Island  
SCHWARZECK–Namibia  
87  
88  
89  
90  
91  
SOUTHEAST BASE–Porto Santo and Madeira Islands  
SOUTHWEST BASE–Faial, Graciosa, Pico, Sao Jorge, and Terceira Islands (Azores)  
TIMBALAI 1948–Brunei and East Malaysia (Sarawak and Sabah)  
TOKYO–Japan, Korea, Okinawa  
TRISTAN ASTRO 1968–Tristan da Cunha  
User defined earth datum  
92  
93  
94  
95  
96  
97  
VITI LEVU 1916–Viti Levu Island (Fiji Islands)  
WAKE-ENIWETOK 1960–Marshall Islands  
WORLD GEODETIC SYSTEM 1972  
WORLD GEODETIC SYSTEM 1984  
ZANDERIJ–Surinam  
98  
99  
100  
101  
102  
103  
104  
105  
106  
107  
108  
109  
CH-1903–Switzerland  
Hu-Tzu-Shan  
Indonesia 74  
Austria  
Potsdam  
Taiwan–modified Hu-Tzu-Shan  
GDA–Geocentric Datum of Australia  
Dutch  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 24  
Download from Www.Somanuals.com. All Manuals Search And Download.  
APPENDIX B: GARMIN BINARY OUTPUT FORMAT  
In Binary Output mode, GPS 18x series products will transmit packets once per second. The record contains  
primarily post-process information such as position and velocity information. For the GPS 18x PC, GPS 18x LVC,  
and GPS 18x-5Hz the record is sent at a default baud rate of 4800 baud, 8 data bits, and no parity.  
To turn this record on for the GPS 18x PC, GPS 18x LVC, and GPS 18x-5Hz versions, use the $PGRMC1 NMEA  
sentence as described in section 4 GPS 18x PC, GPS 18x LVC, & GPS 18x-5Hz Software Interface. Refer to the  
Garmin Device Interface Specification found in the Garmin Device Interface SDK for details on how to form and  
parse Garmin packets. At the time of this printing, these specs are available from the technical suppport section of  
Note: For the GPS 18x-5Hz, a baud rate of 9600 is not high enough to transmit all of the packets (since they are  
output at a 5 Hz rate). You will need to change the baud rate to at least 38400 to be able to transmit all of the  
packets. Refer to Appendix C: Changing the Baud Rate in Garmin Mode for information.  
For the GPS 18x USB, the records must be enabled by commands to the unit. Refer to the Garmin Device Interface  
Specification found in the Garmin Device Interface SDK for details on how to form and parse Garmin packets over  
USB. At the time of this printing, these specs are available from the technical suppport section of our Web site:  
www.garmin.com/support/commProtocol.html. The ID of each command should be 10 decimal to signify that the  
record is a command. The data portion of the packet should be one of the following:  
Function  
Command (base 10)  
Position Record On  
Position Record Off  
49  
50  
Note that the satellite data information is also enabled when the position record is enabled.  
Records sent over RS232 begin with a delimiter byte (10 hex). The second byte identifies the record type (33 hex for  
a position record, 34 hex for a receiver measurement and 72 hex for a satellite data record). The third byte indicates  
the size of the data. The fourth byte is the first byte of data. The data is then followed by a checksum byte, a  
delimiter byte (10 hex), and an end-of-transmission character (03 hex). Additionally, any DLEs (0x10) that appear  
between the delimeters are escaped with a second DLE. There is sample code at the end of this section that will strip  
off the DLEs and ETXs.  
RS232 Packet:  
- 0x10  
(DLE is first byte)  
- 0x##  
(Record ID – single byte)  
- 0x##  
(Number of data bytes – single byte)  
- data bytes  
- 0x##  
(See descriptions below)  
(2’s complement of the arithmetic sum of the bytes between the delimiters)  
- 0x10  
(DLE)  
- 0x03  
(ETX is last byte)  
USB packets contain a header with a USB transport ID, a record ID, and the size of the record data in bytes. All  
unused reserved bytes in the header must be zero. Immediately following the header is the record data payload.  
Refer to the Garmin Device Interface Specification found in the Garmin Device Interface SDK for details on how to  
form and parse Garmin USB packets.  
USB Packet:  
- 0x## 0x00 0x00 0x00 (USB transport ID, 1 byte unsigned, 4 bytes reserved)  
- 0x## 0x## 0x00 0x00 (Record ID, 2 bytes unsigned, 4 bytes reserved)  
- 0x## 0x## 0x## 0x## (Number of data bytes in record, 4 bytes unsigned)  
- record data payload  
The data bytes of each packet contain the record specified by the record ID. A description of each record follows.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 25  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Satellite Data Record  
The satellite data has a record ID of 0x72 with 84 (0x54) data bytes. The data bytes contain data for 12 satellites as  
described below.  
typedef  
{
struct  
uint8  
svid; //space vehicle identification (1–32 and 33–64 for WAAS)  
uint16  
uint8  
uint16  
snr;  
//signal-to-noise ratio  
elev; //satellite elevation in degrees  
azmth; //satellite azimuth in degrees  
status; //status bit-field  
uint8  
} cpo_sat_data;  
The status bit field represents a set of booleans described below:  
Bit  
0
Meaning when bit is one (1)  
The unit has ephemeris data for the specified satellite.  
The unit has a differential correction for the specified satellite.  
The unit is using this satellite in the solution.  
1
2
This pattern is repeated for 12 satellites for a total of 12 X 7 bytes = 84 (0x54) bytes.  
The RS-232 Packet for the Satellite Record looks like:  
- 0x10  
(DLE is first byte)  
- 0x72  
(Record ID – single byte)  
(Number of data bytes – single byte)  
- 0x54  
- 12 cpo_sat_data records  
- 0x##  
- 0x10  
- 0x03  
(2’s complement of the arithmetic sum of the bytes between the delimiters)  
(DLE)  
(ETX is last byte)  
The USB Packet for the Satellite Record looks like:  
- 0x14 0x00 0x00 0x00 (USB Transport ID, 1 byte unsigned, 4 bytes reserved)  
- 0x72 0x00 0x00 0x00 (Record ID, 2 bytes unsigned, 4 bytes reserved)  
- 0x54 0x00 0x00 0x00 (Number of data bytes, 4 bytes unsigned)  
- 12 cpo_sat_data records  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 26  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Position Record  
The Position Record has a record identifier of  
typedef struct  
{
float  
float  
float  
float  
int  
alt;  
epe;  
eph;  
epv;  
fix;  
double  
double  
double  
float  
float  
float  
float  
int  
gps_tow;  
lat;  
lon;  
lon_vel;  
lat_vel;  
alt_vel;  
msl_hght;  
leap_sec;  
grmn_days;  
long  
} cpo_pvt_data;  
alt  
Ellipsoid altitude (meters)  
epe  
eph  
epv  
fix  
Estimated position error (meters)  
Position error, horizontal (meters)  
Position error, vertical (meters)  
0 = no fix; 1 = no fix; 2 = 2D; 3 = 3D; 4 = 2D differential; 5 = 3D differential;  
6 and greater = not defined  
gps_tow  
lat  
GPS time of week (sec)  
Latitude (radians)  
lon  
Longitude (radians)  
lon_vel  
lat_vel  
alt_vel  
msl_hght  
leap_sec  
Longitude velocity (meters/second)  
Latitude velocity (meters/second)  
Altitude velocity (meters/second)  
Height (mean sea level) (meters)  
UTC leap seconds  
grmn_days Garmin days (days since December 31, 1989)  
190-00879-08  
GPS 18x Technical Specifications  
Page 27  
Rev. D  
Download from Www.Somanuals.com. All Manuals Search And Download.  
DLE and ETX bytes:  
Sample C code to receive the two records should filter DLE and ETX bytes as described below:  
typedef enum  
{
DAT,  
DLE,  
ETX  
} rx_state_type;  
/* Declare and initialize static variables */  
static char  
static int  
in_que[ 256 ];  
in_que_ptr = 0;  
static rx_state_type rx_state = DAT;  
.
.
.
void add_to_que( char data )  
{
#define DLE_BYTE 0x10  
#define ETX_BYTE 0x03  
if ( rx_state == DAT )  
{
if ( data == DLE_BYTE )  
{
rx_state = DLE;  
}
else  
{
in_que[ in_que_ptr++ ] = data;  
}
}
else if ( rx_state == DLE )  
{
if ( data == ETX_BYTE )  
{
rx_state = ETX;  
}
else  
{
rx_state = DAT;  
in_que[ in_que_ptr++ ] = data;  
}
}
else if ( rx_state == ETX )  
{
if ( data == DLE_BYTE )  
{
rx_state = DLE;  
}
}
if ( in_que_ptr > 255 )  
{
in_que_ptr = 0;  
}
}
190-00879-08  
GPS 18x Technical Specifications  
Page 28  
Rev. D  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
APPENDIX C: CHANGING THE BAUD RATE IN GARMIN MODE  
In certain cases, you may need to change the default baud rate of your Garmin GPS receiver while in Garmin mode.  
Follow these steps to temporarily change the baud rate.  
Refer to the Garmin Device Interface Specification found in the Garmin Device Interface SDK for details on how to  
form and parse Garmin packets. At the time of this printing, these specs are available from the technical suppport  
1. Turn off all requests by transmitting packet:  
id = IOP_RQST_DATA (0x1C)  
data = 0 (16-bit unsigned integer )  
2. The GPS unit will respond by sending a packet with id = IOP_ACK_BYTE (0x06)  
3. After you receive the above packet, transmit packet:  
id = IOP_BAUD_RQST_DATA (0x30)  
data = baud rate to change to (32-bit unsigned integer; for example, 38400)  
4. The GPS unit will respond by sending a packet:  
id = IOP_BAUD_ACPT_DATA (0x31)  
data = highest acceptable baud rate closest to what was requested  
(32-bit unsigned integer; for example, 38361 decimal)  
5. Determine the actual baud rate value from the data sent in step 4. This value will be within +/- 5% of the actual  
baud rate. (For example, the GPS unit might send a baud rate of 38361, which correlates to a baud rate of  
38400).  
6. If the baud rate in step 5 is acceptable, transmit packet:  
id = IOP_ACK_BYTE (0x06)  
data = IOP_BAUD_ACPT_DATA (0x31)  
7. Sleep for a small amount of time, about 100 milliseconds, to make sure the packet in (6) was successfully  
transmitted to the GPS unit.  
8. Close the current connection to the GPS unit and immediately open a new connection with the new baud rate  
obtained in step 5.  
9. Immediately after establishing a connection, transmit packet:  
id = IOP_CMND_DATA (0x0A)  
data = IOP_ACK_PING (0x3A)  
10. The GPS will respond by sending a packet:  
id = IOP_ACK_BYTE (0x06)  
data = IOP_CMND_DATA (0x0A)  
11. After you receive the above packet, transmit the same packet in step 9 again.  
id = IOP_CMND_DATA (0x0A)  
data = IOP_ACK_PING (0x3A)  
12. The GPS will respond again with the same packet in step 10.  
id = IOP_ACK_BYTE (0x06)  
data = IOP_CMND_DATA (0x0A)  
13. The baud rate has been successfully changed upon receiving the above packet. If the GPS unit does not receive  
these two IOP_CMND_DATA packets within two seconds, it will reset its baud rate to 9600.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 29  
Download from Www.Somanuals.com. All Manuals Search And Download.  
APPENDIX D: GPS 18x PC/ LVC/18x-5HZ & WINDOWS SERIAL MOUSE ISSUE  
Problem: It is possible for Windows to incorrectly interpret the NMEA 0183 output of the GPS 18x PC as the  
output of a Microsoft Serial BallPoint Mouse. When that happens, Windows loads drivers for the Serial BallPoint  
Mouse. This causes the cursor to move erratically about the display, clicking, right clicking, double clicking,  
dragging and dropping displayed items as it goes. On Windows 2000 and Windows XP, you may not experience the  
problem if you wait until after the computer is booted before connecting the GPS 18x PC to the serial  
communications port. This problem is not specific to the GPS 18x PC. Any NMEA 0183 device connected to a  
Windows computer’s serial port is likely to cause this problem. Below are several possible solutions to this problem.  
Note: If your GPS 18x PC came with Garmin nRoute™ Navigation Software, you will not have this problem; the  
unit is programmed to produce data according to the binary format that is described in Appendix B: Garmin Binary  
If you wish to use a different navigation software application with your GPS 18x PC, you will need to de-select the  
“Binary Output Data” option that is discussed in Solution 3 below.  
Solution 1: The easiest solution is to disable the Serial BallPoint mouse in the Device Manager. This solution  
assumes that you do not need to use a Serial BallPoint mouse with your computer. When erratic mouse movements  
occur, follow the steps below.  
1. Unplug the DB9 connector.  
2. Right-click the My Computer icon on your desktop and select Properties to open Device Manager.  
3. Go to the hardware tab of the resulting pop-up window and click on the Device Manager button.  
4. Right-click on Serial BallPoint Mouse and choose the option to Disable (NOT uninstall) this device.  
Solution 2: Do not plug the DB9 connector into the computer until the computer is turned on and the operating  
system is completely booted up and running. Every time you use the GPS 18x PC/LVC, you will need to start the  
computer and operating system before making the connection between the GPS 18x PC and the computer. This  
solution usually works on Windows 2000 and Windows XP computers.  
Solution 3: Change the default output of the GPS 18x PC/LVC so that it does not automatically send NMEA 0183  
data to the computer (change the default configuration to enable “Binary Output Data”). Use the Garmin Sensor  
Configuration Software, named SNSRCFG.EXE, provided on the Web site to enable “Binary Output Data.” To  
download the software, start at www.garmin.com/oem, select the GPS 18x, and then select Updates and  
Downloads.  
Please note that by enabling “Binary Output Data,” the device will no longer appear as a NMEA 0183 device to your  
computer. As a result, mapping applications that expect to hear NMEA 0183 data will not recognize your GPS 18x  
P/LVC until you re-enable the NMEA 0183 output, disabling the “Binary Output Data” in the process.  
Refer to Appendix E: Sensor Configuration Software for complete information about downloading the Sensor  
Configuration Software application.  
After the Sensor Configuration Software is installed and running on your computer, follow the steps below to  
change the default data output of the GPS 18x PC, LVC, or GPS 18x-5Hz.  
1. Select the GPS 18x PC / LVC or the GPS 18x-5Hz from the list  
of sensors and click OK. The Sensor Configuration Software  
opens with the default configuration file for the GPS 18x, as  
shown on the next page.  
2. Select Config > Switch to NMEA Mode (or press the F10 key).  
3. Select Comm > Setup to open the Comm Setup Window.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 30  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
4. Select the serial port to which the GPS 18x  
is connected. Select Auto to have the  
program automatically determine the baud  
rate, or select Manual to manually select  
the baud rate of the GPS 18x. Click OK  
when done.  
5. Click the Connect icon , or select  
Comm > Connect to connect to the GPS  
18x.  
6. To view the current programming of the  
GPS 18x, select Config > Get  
Configuration from GPS (or press the F8  
key). The current programming of the GPS  
18x is displayed in the window, as shown  
on the previous page.  
7. Open the Sensor Configuration Window  
by pressing the F6 key or selecting  
Config > Sensor Configuration.  
8. Place a check mark in the box next to  
“Binary Output Data” to change the GPS  
18x to Garmin Mode. The unit will keep  
this change in the programming until you  
change it again in the software.  
Note: Selecting Config > Switch to  
Garmin Mode (or pressing the F11 key)  
only changes the unit to work in Garmin  
Mode until power is cycled through the  
unit again. For a more permanent  
change, refer to step 8 above.  
9. Click OK.  
10. When you are ready to upload the  
changes into the GPS 18x, select Config  
> Send Configuration to GPS (or press  
the F9 key). The new configuration is  
then loaded into the GPS 18x.  
11. You may disconnect and close the  
software when finished. The software  
configuration can also be saved for  
future reference.  
Software for complete information about downloading the Sensor Configuration Software application.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 31  
Download from Www.Somanuals.com. All Manuals Search And Download.  
APPENDIX E: SENSOR CONFIGURATION SOFTWARE  
The Garmin Sensor Configuration Software (SNSRCFG.exe) configures the GPS sensors based on user-selected  
parameters. Some application features include the ability to download GPS sensor configuration, maintain different  
configurations in files, and perform GPS sensor configurations quickly with the use of one function key.  
This section provides a brief overview of the Sensor Configuration Software. Refer to this section when using the  
software to configure your Garmin sensor.  
Downloading the Sensor Configuration Software  
SNSRCFG.exe is available from the Garmin Web site. To download the  
software, go to www.garmin.com/oem. Click GPS 18x 5Hz or GPS 18x OEM  
(for the GPS 18x USB, 18x PC, and 18x LVC), and click Updates &  
Downloads. SNSRCFG.exe is included in the software update download.  
Selecting a Model  
Double-click SNSRCFG.exe. The Set Base Model to… window appears.  
Select the radio button next to the type of Garmin sensor you are configuring.  
Connecting to the Sensor  
After selecting the type of sensor, the following window opens. This is the  
Main Interface Screen for the program.  
To configure your sensor, you must first  
connect to the sensor.  
1. Select Config > Switch to NMEA  
Mode (or press the F10 key).  
2. Select Comm > Setup to open the  
Comm Setup window.  
3. Select the serial port to which the sensor  
is connected. Select Auto to have the  
program automatically determine the  
baud rate, or select Manual to manually  
select the baud rate of the GPS 18x.  
Click OK.  
4. Click the Connect icon , or select  
Comm > Connect.  
5. To view the current programming of the  
sensor, select Config > Get  
Configuration from GPS (or press the  
F8 key). The current programming of the  
sensor appears as shown in the example  
to the right.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 32  
Download from Www.Somanuals.com. All Manuals Search And Download.  
 
Menus  
File Menu  
The File Menu allows you to open, save, and print sensor configurations. The items in the File Menu work like most  
Windows-based programs.  
Comm Menu  
The Comm (Communication) Menu allows you to set the port number and baud rate, as well as connect to the sensor  
and disconnect from the sensor.  
Setup: Opens the Comm Setup window. Select the serial port to which the  
sensor is connected from the drop-down list. Select Auto (the program  
determines the baud rate on its own) or Manual (you enter the baud rate) for  
the baud rate entry.  
Connect: Select Connect to connect to the sensor in order to change or  
view the configuration.  
Disconnect: Select Disconnect to disconnect from the sensor.  
Config Menu  
The Config (Configuration) Menu allows you  
to configure the sensor as it is connected.  
Sensor Configuration (F6): Opens the  
Sensor Configuration window, shown to the  
right. Many of the fields in this window  
should not be changed. Refer to the beginning  
of this manual for information on many of  
these fields. This window is used to enter a  
new latitude, longitude, and altitude for the  
sensor. This is especially helpful when you  
are programming the sensor for use in a  
particular geographic location.  
Click Reset Unit to perform a reset on the  
unit, much like cycling the power.  
Resetting the non-volatile memory (Reset  
NonVol) clears all of the data from the non-  
volatile memory.  
NMEA Sentence Selections (F7): Displays the NMEA Sentence Selections  
window. If the sentence is enabled, a check mark appears in the box to the left of  
the sentence name. Click the box to enable or disable to the sentence.  
190-00879-08  
GPS 18x Technical Specifications  
Rev. D  
Page 33  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Get Configuration From GPS (F8): Retrieves the current programming from the sensor. The programming is then  
displayed in the Main Interface window.  
Send Configuration To GPS (F9): Sends your updated configuration programming to the sensor.  
Switch to NMEA Mode (F10): Switches the unit to NMEA Mode. The sensor must be in NMEA Mode when  
connected to this software.  
Switch to Garmin Mode (F11): Switches the unit to Garmin Mode.  
Update Software (F12): After you have downloaded a new software version for the sensor, you can update the  
sensor with the new software. Select Update Software and then select the file using the Open dialog box. You must  
locate both the .rgn file and the updater.exe file.  
View Menu  
The View Menu allows you to view the NMEA sentences transmitted by the sensor. You can also customize how  
the program looks by showing and hiding the Toolbar and Status Bar.  
Help Menu  
The Help Menu displays the software version and copyright information.  
For the latest free software updates (excluding map data) throughout the life of your  
Garmin products, visit the Garmin Web site at www.garmin.com.  
© 2008–2011 Garmin Ltd. or its subsidiaries  
Garmin International, Inc.  
1200 East 151st Street, Olathe, Kansas 66062, USA  
Garmin (Europe) Ltd.  
Liberty House, Hounsdown Business Park, Southampton, Hampshire, SO40 9LR UK  
Garmin Corporation  
No. 68, Zhangshu 2nd Road, Xizhi Dist., New Taipei City, 221, Taiwan (R.O.C.)  
Part Number 190-00879-08 Rev. D  
Download from Www.Somanuals.com. All Manuals Search And Download.  

Echo Blower PAS 225 User Manual
Electro Voice Portable Speaker EVS 14B User Manual
Electro Voice Speaker Premium Surface Mount Speakers User Manual
Fender Guitar 015 0082 User Manual
Fisher Price Baby Swing 75960 User Manual
Furuno TV Video Accessories FCV 662 User Manual
GE Monogram Cooktop ZGG300LBPSS User Manual
GE Refrigerator 162D9617P005 User Manual
Giant Septic System P420A 3100 User Manual
Gitzo Camcorder Accessories G2227 User Manual