Garmin Proprietary NMEA 0183 Sentences TECHNICAL SPECIFICATIONS
Garmin International, Inc. 1200 E. 151st Street Olathe, KS 66062 USA 190-00684-00, Revision C December 2008
Copyright 2008 Garmin Ltd. or its subsidiaries Garmin International, Inc. 1200 East 151st Street, Olathe, Kansas 66062, USA Tel. (913) 397.8200 or (800) 800.1020 Fax (913) 397.8282 Garmin (Europe) Ltd. Liberty House, Hounsdown Business Park Southampton, Hampshire, SO40 9RB UK Tel. +44 (0) 870.8501241 (outside the UK) (within the UK) Fax +44 (0) 870.8501251 Garmin Corporation No. 68, Jangshu 2nd Road, Shijr, Taipei County, Taiwan Tel. 886/2.2642.9199 Fax 886/2.2642.9099 All rights reserved. Except as expressly provided herein, no part of this manual may be reproduced, copied, transmitted, disseminated, downloaded or stored in any storage medium, for any purpose without the express prior written consent of Garmin. Garmin hereby grants permission to download a single copy of this manual onto a hard drive or other electronic storage medium to be viewed and to print one copy of this manual or of any revision hereto, provided that such electronic or printed copy of this manual must contain the complete text of this copyright notice and provided further that any unauthorized commercial distribution of this manual or any revision hereto is strictly prohibited. Information in this document is subject to change without notice. Garmin reserves the right to change or improve its products and to make changes in the content without obligation to notify any person or organization of such changes or improvements. Visit the Garmin Web site (www.garmin.com) for current updates and supplemental information concerning the use and operation of this and other Garmin products. Garmin is a trademark of Garmin Ltd. or its subsidiaries, registered in the USA and other countries. Web site address: www.garmin.com
RECORD OF REVISIONS Revision A B C Revision Date 04/21/06 04/24/06 12/30/08 Description Initial Release Revised and redrawn Added PGRMW sentence ECO # -37482 58677

190-00684-00

Garmin Proprietary NMEA Sentences Technical Specifications Page ii

Rev. C

TABLE OF CONTENTS Introduction....1
1.1 Garmin Proprietary NMEA Sentences....1
GPS Receiver Software Interface...1
2.1 Received NMEA 0183 Sentences....1
2.1.1 2.1.2 2.1.3 2.1.4 2.1.5 2.2.1 2.2.2 2.2.3 2.2.4 2.2.5 2.2.6 2.2.7 2.2.8 2.2.9 Sensor Initialization Information (PGRMI)... 1 Sensor Configuration Information (PGRMC)... 2 Additional Sensor Configuration Information (PGRMC1)... 2 Output Sentence Enable/Disable (PGRMO).... 3 Additional Waypoint Information (PGRMW)... 3 Sentence Transmission Rate.... 4 Estimated Error Information (PGRME).... 5 GPS Fix Data Sentence (PGRMF).... 5 Aviation Height and VNAV Data (PGRMH)... 5 Map Datum (PGRMM).... 5 Sensor Status Information (PGRMT)... 5 3D velocity Information (PGRMV).... 6 Altitude (PGRMZ).... 6 DGPS Beacon Information (PGRMB).... 6
2.2 Transmitted NMEA 0183 Sentences....4
Appendix A: Earth Datums.....7
LIST OF TABLES AND FIGURES
Table 1: NMEA 0183 Output Sentence Order and Size... 4 Table 2: Characters per Second for Available Baud Rates.... 4
Garmin Proprietary NMEA Sentences Technical Specifications Page iii
INTRODUCTION GARMIN PROPRIETARY NMEA SENTENCES
Garmin Proprietary NMEA sentences are designed for use with Garmin GPS sensors and GPS units in order to interface with external devices for data interpretation and recording. Refer to your Garmin Product Owners Manual to determine the specific sentences supported by your product. NOTE: Not all Garmin GPS units support NMEA interfaces. For those devices that do not support NMEA 0183, refer to the Garmin Device Interface SDK for specific information about the Garmin Protocol. The Garmin Device Interface SDK is located on the Garmin Web site at http://www.garmin.com/support/ commProtocol.html.
GPS RECEIVER SOFTWARE INTERFACE
The interface protocol design of most Garmin products is based on the National Marine Electronics Associations NMEA 0183 ASCII interface specification. This standard is fully defined in NMEA 0183, Version 2.30. Copies may be obtained from NMEA, http://www.nmea.org/. In addition to the standard NMEA 0183 sentences, Garmin GPS receivers may transmit or receive 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 Garmins proprietary sentence. The letter (or letters) that follow the characters $PGRM uniquely identifies that particular Garmin proprietary sentence.

RECEIVED NMEA 0183 SENTENCES
The following paragraphs define the sentences that can be received on a GPS units port. Null fields in the configuration sentence indicate no change in the particular configuration parameter. All sentences received by the GPS unit 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, noninclusive. Any letters used in the hex representation must be capitalized, 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 GPS unit.
Sensor Initialization Information (PGRMI)
The $PGRMI sentence provides information used to initialize the GPS sensors 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 contains 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> <2> <3> <4> <5> <6> <7> Latitude, ddmm.mmm format (leading zeros must be transmitted) Latitude hemisphere, N or S Longitude, dddmm.mmm format (leading zeros must be transmitted) Longitude hemisphere, E or W Current UTC date, ddmmyy format Current UTC time, hhmmss format Receiver Command, A = Auto Locate, R = Unit Reset
Garmin Proprietary NMEA Sentences Technical Specifications Page 1

Sensor Configuration Information (PGRMC)
The $PGRMC sentence provides information used to configure a GPS sensors 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 contains 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> <4> <5> <6> <7> <8> <9> Fix mode, A = automatic, 2 = 2D exclusively (host system must supply altitude), 3 = 3D exclusively Altitude above/below mean sea level, -1500.0 to 10000.0 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 your Appendix A for a list of earth datums and the corresponding earth datum index. 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> NMEA 0183 Baud rate, 1 = 1200, 2 = 2400, 3 = 4800, 4 = 9600, 5 = 19200, 6 = 300, 7 = 600 <11> Velocity filter, 0 = No filter, 1 = Automatic filter, 2-255 = Filter time constant (e.g., 10 = 10 second filter) <12> Not used <13> Not used <14> Dead reckoning valid time 1-30 (sec) All configuration changes take effect after receipt of a valid value except baud rate. Baud rate change takes effect on the next power cycle or an external reset event.

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 echos this sentence upon its receipt if no errors are detected. If an error is detected, the echoed PGRMC1 sentence contains 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>*hh<CR><LF> <1> NMEA 0183 output time 1-900 (sec) <2> Binary Phase Output Data, 1 = Off, 2 = On. <3> Automatic Position Averaging when Stopped, 1 = Off, 2 = On <4> No Effect (DGPS beacon frequency 0.0, 283.5 325.0 kHz in 0.5 kHz steps) <5> No Effect (DGPS beacon bit rate 0, 25, 50, 100, or 200 bps) <6> No Effect (DGPS beacon scanning, 1 = Off, 2 = On) <7> NMEA 0183 version 2.30 mode indicator, 1 = Off, 2 = On <8> DGPS mode, W = WAAS Only, N = None (DGPS disabled) <9> Power Save Mode for GPS, P = Power Save mode, N = Normal <10> Adaptive Transmission Enabled, 1 = Off, 2 = On <11> Auto Power Off, 1 = Off, 2 = On <12> Power On with External Charger, 1 = Off, 2 = On Configuration changes take effect immediately, with the exception of Binary Phase Output Data, which takes effect on the next power cycle or a reset event. A reset can be commanded by sending the sentence $PGRMI,,,,,,,R (refer to Section 2.1.1 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 190-00684-00 Garmin Proprietary NMEA Sentences Technical Specifications Page 2 Rev. C
the data format to NMEA 0183. Then follow by sending a PGRMC1 sentence that turns off the Binary Phase Output Data format: 10 0A 00 CE (Hexadecimal)
Output Sentence Enable/Disable (PGRMO)
The $PGRMO sentence provides the ability to enable and disable specific output sentences. $PGRMO,<1>,<2>*hh<CR><LF> Target sentence description (e.g., 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: 1. 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 (e.g., $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 causes the GPS sensor to transmit all stored almanac information. All other NMEA 0183 sentence transmission will be suspended temporarily. $PGRMO,,G causes the COM port to change to Garmin Data Transfer format for the duration of the power cycle. The Garmin mode is required for GPS 10, GPS 15L, GPS 15H, GPS 16, GPS 17, and GPS 18 series product software updates. <1> <2>

2. 3. 4. 5.

Additional Waypoint Information (PGRMW)
The $PGRMW sentence provides the ability to update a waypoints symbol, altitude, and comment. $PGRMW,<1>,<2>,<3>,<4>*hh<CR><LF> Waypoint identifier Altitude in meters Symbol number in Hexadecimal up to FFFF. Uses the enumerated values as defined for symbol_type. <4> Comment string The following notes apply to the PGRMW input sentence: 1. 2. 3. 4. The waypoint identifier must exactly match an existing waypoint on the unit. If the unit cannot find a waypoint that matches the given identifier, the rest of the sentence will be ignored. See Garmin Device Interface Specification 001-0063-00 for enumerated values of symbol_type. If the comment string contains more characters than the unit supports, the unit will ignore any characters beyond the size allotted for comments. Not all units support this sentence. <1> <2> <3>
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TRANSMITTED NMEA 0183 SENTENCES
The subsequent paragraphs define the sentences that can be transmitted.
Sentence Transmission Rate
Sentences are transmitted with respect to the user selected baud rate. The GPS unit transmits 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 unit transmits the selected sentences contiguously. The length of the transmission can be determined by the following equation and Tables 2 and 3: length of transmission = total characters to be transmitted --------------------------------------------characters transmitted per second
Sentence GPRMC GPGGA GPGSA GPGSV PGRME GPGLL GPVTG PGRMV PGRMF PGRMB PGRMT
Output Rate Maximum Characters Once per record* 74 Once per record* 82 Once per record* 66 Once per record* 70 Once per record* 35 Once per record* 44 Once per record* 42 Once per record* 32 Once per record* 82 Once per record* 40 Once per minute* 50 *if enabled
Table 1: NMEA 0183 Output Sentence Order and Size Baud Characters per Second Table 2: 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>. The factory set defaults result in a once per second transmission at the NMEA 0183 specification transmission rate of 4800 baud. Some Garmin products implement a one-pulse-per-second output, the rising edge of which is aligned to the UTC second boundary to within one microsecond for all conditions in which the receiver has reported a valid and accurate position for at least the previous four seconds. 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). NMEA 0183 sentences are listed in order of their occurrence within a record.

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<1> <2> <3>
Estimated Error Information (PGRME)
$PGRME,<1>,M,<2>,M,<3>,M*hh<CR><LF> 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
<1> <2> <3> <4> <5> <6> <7> <8> <9> <10> <11> <12> <13> <14> <15>
GPS Fix Data Sentence (PGRMF)
$PGRMF,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>,<15>*hh<CR><LF> GPS week number (0 - 1023) GPS seconds (0 - 604799) UTC date of position fix, ddmmyy format UTC time of position fix, hhmmss format GPS leap second count Latitude, ddmm.mmmm format (leading zeros will be transmitted) Latitude hemisphere, N or S Longitude, dddmm.mmmm format (leading zeros will be transmitted) Longitude hemisphere, E or W Mode, M = manual, A = automatic Fix type, 0 = no fix, 1 = 2D fix, 2 = 3D fix Speed over ground, 0 to 1051 kilometers/hour Course over ground, 0 to 359 degrees, true Position dilution of precision, 0 to 9 (rounded to nearest integer value) Time dilution of precision, 0 to 9 (rounded to nearest integer value)
<1> <2> <3> <4> <5> <6> <7> <8>
Aviation Height and VNAV Data (PGRMH)
$PGRMH,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>hh<CR><LF> Data status: A = data valid, v = data unusable Vertical speed, feet per minute: negative = down, positive = up VNAV profile error, feet: -999 ft (below VNAV profile) to 999 ft (above VNAV profile) Vertical speed to VNAV target, feet per minute: negative = down, positive = up Vertical speed to next waypoint, feet per minute: negative = down, positive = up Approximate height above terrain, feet (rounded to next lowest 100 feet) Desired track, degrees true Course of next route leg after active waypoint, degrees true

2.2.5 Map Datum (PGRMM)

$PGRMM,<1> *hh<CR><LF> <1> Current map datum (variable length field, for example, WGS 84)

Sensor Status Information (PGRMT)
The Garmin Proprietary sentence $PGRMT gives information concerning the status of a 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> <2> <3> <4> <5> <6> <7> <8> <9> 190-00684-00 Product, model and software version (variable length field, e.g., GPS 10 SW VER 2.01 BT VER 1.27 764) ROM checksum test, P = pass, F = fail Receiver failure discrete, P = pass, F = fail Stored data lost, R = retained, L = lost Real time clock lost, R = retained, L = lost Oscillator drift discrete, P = pass, F = excessive drift detected Data collection discrete, C = collecting, null if not collecting GPS sensor temperature in degrees C GPS sensor configuration data, R = retained, L = lost Garmin Proprietary NMEA Sentences Technical Specifications Page 5 Rev. C
3D velocity Information (PGRMV)
$PGRMV,<1>,<2>,<3>*hh<CR><LF> True east velocity, 514.4 to 514.4 meters/second True north velocity, 514.4 to 514.4 meters/second Up velocity, 999.9 to 9999.9 meters/second

<1> <2>

Altitude (PGRMZ)
$PGRMZ,<1>, f, <2>,<3>*hh<CR><LF> Current altitude, feet Fix type: 1 = no fix, 2 = 2D fix, 3 = 3D fix
DGPS Beacon Information (PGRMB)
$PGRMB,<1>,<2>,<3>,<4>,<5>,K,<6>,<7>*hh<CR><LF> Beacon tune frequency, 0.0, 283.5 325.0 kHz in 0.5 kHz steps Beacon bit rate, 0, 25, 50, 100, or 200 bps Beacon SNR, 0 to 31 Beacon data quality, 0 to 100 Distance to beacon reference station in kilometers Beacon receiver communication status (0 = Check Wiring, 1 = No Signal, 2 = Tuning, 3 = Receiving, 4= Scanning) DGPS fix source (R = RTCM, W = WAAS, N = Non-DGPS Fix) DGPS mode, A = Automatic, W = WAAS Only, R = RTCM Only, N = None (DGPS disabled)
Important Note: Garmin units equipped with Sirf technology chipsets do not support this proprietary sentence.
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APPENDIX A: EARTH DATUMS

The following is a list of the Garmin GPS 10 Earth datum indices and the corresponding earth datum name (including the area of application). NOTE: New datums are always added at the end of the list found on your Garmin GPS device. ADINDAN - Ethiopia, Mali, Senegal, Sudan AFGOOYE - Somalia AIN EL ABD 1970 - Bahrain Island, Saudi Arabia ANNA 1 ASTRO 1965 - Cocos Island ARC 1950 - Botswana, Lesotho, Malawi, Swaziland, Zaire, Zambia, Zimbabwe ARC 1960 - Kenya, Tanzania ASCENSION ISLAND 1958 - Ascension Island ASTRO BEACON E - Iwo Jima Island AUSTRALIAN GEODETIC 1966 - Australia, Tasmania Island 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 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 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 GUAM 1963 - Guam Island GUX 1 ASTRO - Guadalcanal Island HJORSEY 1955 - Iceland Garmin Proprietary NMEA Sentences Technical Specifications Page 7 Rev. C

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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.
Copyright 2008 Garmin Ltd. or its subsidiaries Garmin International, Inc. 1200 East 151st Street, Olathe, Kansas 66062, U.S.A. Garmin (Europe) Ltd. Liberty House, Hounsdown Business Park, Southampton, Hampshire, SO40 9RB UK Garmin Corporation No. 68, Jangshu 2nd Road, Shijr, Taipei County, Taiwan www.garmin.com December 2008 Part Number 190-00684-00 Rev. C