The NMEA 0183 Protocol

Table of Contents
1. 2. 3. 4. 5. 6. 7. 8. What is the NMEA 0183 Standard? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 1 Electrical Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 General Sentence Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Talker Identifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Sentence Identifiers and Sentence Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Some Proprietary Sentences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Manufacturer Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

The material presented in this document has been compiled from various inofficial sources. It is neither a complete nor error-free description of the NMEA 0183 standard. In particular, it does not cover the new sentences and the high-speed interface defined in version 3.x. Klaus Betke, May 2000. Revised August 2001.

1. What is the NMEA 0183 Standard?
The National Marine Electronics Association (NMEA) is a non-profit association of manufacturers, distributors, dealers, educational institutions, and others interested in peripheral marine electronics occupations. The NMEA 0183 standard defines an electrical interface and data protocol for communications between marine instrumentation. NMEA 0183 is a voluntary industry standard, first released in March of 1983. It has been updated from time to time; the latest release, currently (August 2001) Version 3.0, July 2001, is available from the NMEA office (Warning: the price for non-members is 250 US$). P O Box 3435 New Bern NC 28564-3435 USA www.nmea.org NMEA has also established a working group to develop a new standard for data communications among shipboard electronic devices. The new standard, NMEA 2000, is a bi-directional, multi-transmitter, multi-receiver serial data network. It is multi-master and self-configuring, and there is no central controller. The NMEA began a beta testing period in January 2000 with eleven manufacturers. A release version of NMEA 2000 is expected in 2001.

The NMEA 0183 Protocol

2

2. Electrical Interface
NMEA 0183 devices are designated as either talkers or listeners (with some devices being both), employing an asynchronous serial interface with the following parameters: Baud rate: Number of data bits: Stop bits: Parity: Handshake: 4800 8 (bit 7 is 0) 1 (or more) none none

NMEA 0183 allows a single talker and several listeners on one circuit. The recommended interconnect wiring is a shielded twisted pair, with the shield grounded only at the talker. The standard dos not specify the use of a particular connector. Note: The new 0183-HS standard (HS = high speed) introduced in version 3.0 uses a 3-wire interface and a baud rate of 38400. This type of interface is not discussed here. Its is recommended that the talker output comply with EIA RS-422, a differential system with two signal lines, "A" and "B". Differential drive signals have no reference to ground and are more immune to noise. However, a single-ended line at TTL level is accepted as well. The voltages on the A line correspond to those on the TTL single wire, while the B voltages are inverted (when output A is at +5 V, output B is at 0 V, and vice versa. This is the unipolar RS-422 operation. In bipolar mode ±5 V are used). In either case, the recommended receive circuit uses an opto-isolator with suitable protection circuitry. The input should be isolated from the receiver's ground. In practice, the single wire, or the RS-422 "A" wire may be directly connected to a computer's RS-232 input. In fact even many of the latest products, like hand-held GPS receivers, do not have a RS-422 differential output, but just a single line with TTL or 5 V CMOS compatible signal level.

3. General Sentence Format
All data is transmitted in the form of sentences. Only printable ASCII characters are allowed, plus CR (carriage return) and LF (line feed). Each sentence starts with a "$" sign and ends with . There are three basic kinds of sentences: talker sentences, proprietary sentences and query sentences. Talker Sentences. The general format for a talker sentence is:
$ttsss,d1,d2,....

The first two letters following the „$” are the talker identifier. The next three characters (sss) are the sentence identifier, followed by a number of data fields separated by commas, followed by an optional checksum, and terminated by carriage return/line feed. The data fields are uniquely defined for each sentence type. An example talker sentence is:
$HCHDM,238,M

where "HC" specifies the talker as being a magnetic compass, the "HDM" specifies the magnetic heading message follows. The "238" is the heading value, and "M" designates the heading value as magnetic. A sentence may contain up to 80 characters plus "$" and CR/LF. If data for a field is not available, the field is omitted, but the delimiting commas are still sent, with no space between them. The checksum field consists of a "*" and two hex digits representing the exclusive OR of all characters between, but not including, the "$" and "*". Proprietary Sentences. The standard allows individual manufacturers to define proprietary sentence formats. These sentences start with "$P", then a 3 letter manufacturer ID, followed by whatever data the manufacturer wishes, following the general format of the standard sentences. Some proprietary sentences, mainly from Garmin, Inc., are listed in chapter 6.

The NMEA 0183 Protocol

3

Query sentences. A query sentence is a means for a listener to request a particular sentence from a talker. The general format is:
$ttllQ,sss,[CR][LF]

The first two characters of the address field are the talker identifier of the requester and the next two characters are the talker identifier of the device being queried (listener). The fifth character is always a "Q" defining the message as a query. The next field (sss) contains the three letter mnemonic of the sentence being requested. An example query sentence is:
$CCGPQ,GGA

where the "CC" device (computer) is requesting from the "GP" device (a GPS unit) the "GGA" sentence. The GPS will then transmit this sentence once per second until a different query is requested.

4. Talker Identifiers
AG AP CD CR CS CT CV CX DF EC EP ER GP HC HE HN II IN LC P RA SD SN SS TI VD DM VW WI YX ZA ZC ZQ ZV Autopilot - General Autopilot - Magnetic Communications – Digital Selective Calling (DSC) Communications – Receiver / Beacon Receiver Communications – Satellite Communications – Radio-Telephone (MF/HF) Communications – Radio-Telephone (VHF) Communications – Scanning Receiver Direction Finder Electronic Chart Display & Information System (ECDIS) Emergency Position Indicating Beacon (EPIRB) Engine Room Monitoring Systems Global Positioning System (GPS) Heading – Magnetic Compass Heading – North Seeking Gyro Heading – Non North Seeking Gyro Integrated Instrumentation Integrated Navigation Loran C Proprietary Code RADAR and/or ARPA Sounder, Depth Electronic Positioning System, other/general Sounder, Scanning Turn Rate Indicator Velocity Sensor, Doppler, other/general Velocity Sensor, Speed Log, Water, Magnetic Velocity Sensor, Speed Log, Water, Mechanical Weather Instruments Transducer Timekeeper – Atomic Clock Timekeeper – Chronometer Timekeeper – Quartz Timekeeper – Radio Update, WWV or WWVH

The NMEA 0183 Protocol

4

5. Sentence Identifiers and Formats
AAM Waypoint Arrival Alarm

1 2 3 4 5 6 | | | | | | $--AAM,A,A,x.x,N,c--c*hh 1) 2) 3) 4) 5) 6) Status, BOOLEAN, A = Arrival circle entered Status, BOOLEAN, A = perpendicular passed at waypoint Arrival circle radius Units of radius, nautical miles Waypoint ID Checksum

ALM

GPS Almanac Data

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | | | | | | | | | | | | | | | | $--ALM,x.x,x.x,xx,x.x,hh,hhhh,hh,hhhh,hhhh,hhhhhh,hhhhhh,hhhhhh,hhhhhh,hhh,hhh,*hh 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) 15) 16) Total number of messages Message Number Satellite PRN number (01 to 32) GPS Week Number: Date and time in GPS is computed as number of weeks from 6 January 1980 plus number of seconds into the week. SV health, bits 17-24 of each almanac page Eccentricity Almanac Reference Time Inclination Angle Rate of Right Ascension Root of semi-major axis Argument of perigee Longitude of ascension node Mean anomaly F0 Clock Parameter F1 Clock Parameter Checksum

APA

Autopilot Sentence "A"

1 2 3 4 5 6 7 8 9 10 11 | | | | | | | | | | | $--APA,A,A,x.xx,L,N,A,A,xxx,M,c---c*hh 1) Status V = LORAN-C Blink or SNR warning A = general warning flag or other navigation systems when a reliable fix is not available 2) Status V = Loran-C Cycle Lock warning flag A = OK or not used 3) Cross Track Error Magnitude 4) Direction to steer, L or R 5) Cross Track Units (Nautic miles or kilometres) 6) Status A = Arrival Circle Entered 7) Status A = Perpendicular passed at waypoint 8) Bearing origin to destination 9) M = Magnetic, T = True 10) Destination Waypoint ID 11) checksum

The NMEA 0183 Protocol

5

APB

Autopilot Sentence "B"

13 15 1 2 3 4 5 6 7 8 9 10 11 12| 14| | | | | | | | | | | | | | | | $--APB,A,A,x.x,a,N,A,A,x.x,a,c--c,x.x,a,x.x,a*hh 1) Status V = LORAN-C Blink or SNR warning A = general warning flag or other navigation systems when a reliable fix is not available 2) Status V = Loran-C Cycle Lock warning flag A = OK or not used 3) Cross Track Error Magnitude 4) Direction to steer, L or R 5) Cross Track Units, N = Nautical Miles 6) Status A = Arrival Circle Entered 7) Status A = Perpendicular passed at waypoint 8) Bearing origin to destination 9) M = Magnetic, T = True 10) Destination Waypoint ID 11) Bearing, present position to Destination 12) M = Magnetic, T = True 13) Heading to steer to destination waypoint 14) M = Magnetic, T = True 15) Checksum

ASD

Autopilot System Data

Format unknown

BEC

Bearing & Distance to Waypoint – Dead Reckoning

12 1 2 3 4 5 6 7 8 9 10 11| 13 | | | | | | | | | | | | | $--BEC,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x.x,T,x.x,M,x.x,N,c--c*hh 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) Time (UTC) Waypoint Latitude N = North, S = South Waypoint Longitude E = East, W = West Bearing, True T = True Bearing, Magnetic M = Magnetic Nautical Miles N = Nautical Miles Waypoint ID Checksum

The NMEA 0183 Protocol

6

BOD

Bearing – Waypoint to Waypoint

1 2 3 4 5 6 7 | | | | | | | $--BOD,x.x,T,x.x,M,c--c,c--c*hh 1) 2) 3) 4) 5) 6) 7) Bearing Degrees, TRUE T = True Bearing Degrees, Magnetic M = Magnetic TO Waypoint FROM Waypoint Checksum

BWC

Bearing and Distance to Waypoint – Latitude, N/S, Longitude, E/W, UTC, Status

11 1 2 3 4 5 6 7 8 9 10 | 12 13 | | | | | | | | | | | | | $--BWC,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x.x,T,x.x,M,x.x,N,c--c*hh 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) Time (UTC) Waypoint Latitude N = North, S = South Waypoint Longitude E = East, W = West Bearing, True T = True Bearing, Magnetic M = Magnetic Nautical Miles N = Nautical Miles Waypoint ID Checksum

BWR

Bearing and Distance to Waypoint – Rhumb Line Latitude, N/S, Longitude, E/W, UTC, Status

11 1 2 3 4 5 6 7 8 9 10 | 12 13 | | | | | | | | | | | | | $--BWR,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x.x,T,x.x,M,x.x,N,c--c*hh 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) Time (UTC) Waypoint Latitude N = North, S = South Waypoint Longitude E = East, W = West Bearing, True T = True Bearing, Magnetic M = Magnetic Nautical Miles N = Nautical Miles Waypoint ID Checksum

The NMEA 0183 Protocol

7

BWW

Bearing – Waypoint to Waypoint

1 2 3 4 5 6 7 | | | | | | | $--BWW,x.x,T,x.x,M,c--c,c--c*hh 1) 2) 3) 4) 5) 6) 7) Bearing Degrees, TRUE T = True Bearing Degrees, Magnetic M = Magnetic TO Waypoint FROM Waypoint Checksum

DBK

Depth Below Keel

1 2 3 4 5 6 7 | | | | | | | $--DBK,x.x,f,x.x,M,x.x,F*hh 1) 2) 3) 4) 5) 6) 7) Depth, feet f = feet Depth, meters M = meters Depth, Fathoms F = Fathoms Checksum

DBS

Depth Below Surface

1 2 3 4 5 6 7 | | | | | | | $--DBS,x.x,f,x.x,M,x.x,F*hh 1) 2) 3) 4) 5) 6) 7) Depth, feet f = feet Depth, meters M = meters Depth, Fathoms F = Fathoms Checksum

DBT

Depth Below Transducer

1 2 3 4 5 6 7 | | | | | | | $--DBT,x.x,f,x.x,M,x.x,F*hh 1) 2) 3) 4) 5) 6) 7) Depth, feet f = feet Depth, meters M = meters Depth, Fathoms F = Fathoms Checksum

DCN

Decca Position

obsolete

The NMEA 0183 Protocol

8

DPT

Heading – Deviation & Variation

1 2 3 | | | $--DPT,x.x,x.x*hh 1) Depth, meters 2) Offset from transducer; positive means distance from transducer to water line, negative means distance from transducer to keel 3) Checksum

DSC

Digital Selective Calling Information

Format unknown

DSE

Extended DSC

Format unknown

DSI

DSC Transponder Initiate

Format unknown

DSR

DSC Transponder Response

Format unknown

DTM

Datum Reference

Format unknown

FSI

Frequency Set Information

1 2 3 4 5 | | | | | $--FSI,xxxxxx,xxxxxx,c,x*hh 1) 2) 3) 4) 5) Transmitting Frequency Receiving Frequency Communications Mode (NMEA Syntax 2) Power Level Checksum

GBS

GPS Satellite Fault Detection

Format unknown

The NMEA 0183 Protocol

9

GGA

Global Positioning System Fix Data. Time, Position and fix related data for a GPS receiver

11 1 2 3 4 5 6 7 8 9 10 | 12 13 14 15 | | | | | | | | | | | | | | | $--GGA,hhmmss.ss,llll.ll,a,yyyyy.yy,a,x,xx,x.x,x.x,M,x.x,M,x.x,xxxx*hh 1) 2) 3) 4) 5) 6) Time (UTC) Latitude N or S (North or South) Longitude E or W (East or West) GPS Quality Indicator, 0 - fix not available, 1 - GPS fix, 2 - Differential GPS fix Number of satellites in view, 00 - 12 Horizontal Dilution of precision Antenna Altitude above/below mean-sea-level (geoid) Units of antenna altitude, meters Geoidal separation, the difference between the WGS-84 earth ellipsoid and mean-sea-level (geoid), "-" means mean-sea-level below ellipsoid Units of geoidal separation, meters Age of differential GPS data, time in seconds since last SC104 type 1 or 9 update, null field when DGPS is not used Differential reference station ID, 0000-1023 Checksum

7) 8) 9) 10) 11) 12) 13) 14) 15)

GLC

Geographic Position, Loran-C

12 14 1 2 3 4 5 6 7 8 9 10 11| 13| | | | | | | | | | | | | | | $--GLC,xxxx,x.x,a,x.x,a,x.x,a.x,x,a,x.x,a,x.x,a*hh 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) GRI Microseconds/10 Master TOA Microseconds Master TOA Signal Status Time Difference 1 Microseconds Time Difference 1 Signal Status Time Difference 2 Microseconds Time Difference 2 Signal Status Time Difference 3 Microseconds Time Difference 3 Signal Status Time Difference 4 Microseconds Time Difference 4 Signal Status Time Difference 5 Microseconds Time Difference 5 Signal Status Checksum

GLL

Geographic Position – Latitude/Longitude

1 2 3 4 5 6 7 | | | | | | | $--GLL,llll.ll,a,yyyyy.yy,a,hhmmss.ss,A*hh 1) 2) 3) 4) 5) 6) 7) Latitude N or S (North or South) Longitude E or W (East or West) Time (UTC) Status A - Data Valid, V - Data Invalid Checksum

The NMEA 0183 Protocol

10

GRS

GPS Range Residuals

Format unknown

GST

GPS Pseudorange Noise Statistics

Format unknown

GSA

GPS DOP and active satellites

1 2 3 14 15 16 17 18 | | | | | | | | $--GSA,a,a,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x.x,x.x,x.x*hh 1) Selection mode 2) Mode 3) ID of 1st satellite used for fix 4) ID of 2nd satellite used for fix ... 14) ID of 12th satellite used for fix 15) PDOP in meters 16) HDOP in meters 17) VDOP in meters 18) Checksum

GSV

Satellites in view

1 2 3 4 5 6 7 n | | | | | | | | $--GSV,x,x,x,x,x,x,x,...*hh 1) total number of messages 2) message number 3) satellites in view 4) satellite number 5) elevation in degrees 6) azimuth in degrees to true 7) SNR in dB more satellite infos like 4)-7) n) Checksum

GTD

Geographic Location in Time Differences

1 2 3 4 5 6 | | | | | | $--GTD,x.x,x.x,x.x,x.x,x.x*hh 1) 2) 3) 4) 5) n) time difference time difference time difference time difference time difference Checksum

GXA

TRANSIT Position – Latitude/Longitude, Location and Time of TRANSIT Fix at Waypoint

obsolete

The NMEA 0183 Protocol

11

HDG

Heading – Deviation & Variation

1 2 3 4 5 6 | | | | | | $--HDG,x.x,x.x,a,x.x,a*hh 1) 2) 3) 4) 5) 6) Magnetic Magnetic Magnetic Magnetic Magnetic Checksum Sensor heading in degrees Deviation, degrees Deviation direction, E = Easterly, W = Westerly Variation degrees Variation direction, E = Easterly, W = Westerly

HDM

Heading – Magnetic

1 2 3 | | | $--HDM,x.x,M*hh 1) Heading Degrees, magnetic 2) M = magnetic 3) Checksum

HDT

Heading – True

1 2 3 | | | $--HDT,x.x,T*hh 1) Heading Degrees, true 2) T = True 3) Checksum

HSC

Heading Steering Command

1 2 3 4 5 | | | | | $--HSC,x.x,T,x.x,M,*hh 1) 2) 3) 4) 5) Heading Degrees, True T = True Heading Degrees, Magnetic M = Magnetic Checksum

The NMEA 0183 Protocol

12

LCD

Loran-C Signal Data

1 2 3 4 5 6 7 8 9 10 11 12 13 14 | | | | | | | | | | | | | | $--LCD,xxxx,xxx,xxx,xxx,xxx,xxx,xxx,xxx,xxx,xxx,xxx,xxx,xxx*hh 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) GRI Microseconds/10 Master Relative SNR Master Relative ECD Time Difference 1 Microseconds Time Difference 1 Signal Status Time Difference 2 Microseconds Time Difference 2 Signal Status Time Difference 3 Microseconds Time Difference 3 Signal Status Time Difference 4 Microseconds Time Difference 4 Signal Status Time Difference 5 Microseconds Time Difference 5 Signal Status Checksum

MSK

MSK Receiver Interface (for DGPS Beacon Receivers)

1 2 3 4 5 6 | | | | | | $GPMSK,xxx.x,xx,xxx,xx,N*hh 1) Frequency in kHz (283.5 to 325.0) 2) Frequency Selection M1 = Manual A1 = Automatic (field 1 empty) 3) MSK bit rate (100 or 200) 4) Bit Rate Selection M2 = Manual A2 = Automatic (field 3 empty) 5) Period of output of performance status message, 0 to 100 seconds ($CRMSS) 6) Checksum

MSS

MSK Receiver Signal Status

Format unknown

MWD

Wind Direction & Speed

Format unknown

MTW

Water Temperature

1 2 3 | | | $--MTW,x.x,C*hh 1) Degrees 2) Unit of Measurement, Celcius 3) Checksum

The NMEA 0183 Protocol

13

MWV

Wind Speed and Angle

1 2 3 4 5 | | | | | $--MWV,x.x,a,x.x,a*hh 1) 2) 3) 4) 5) 6) Wind Angle, 0 to 360 degrees Reference, R = Relative, T = True Wind Speed Wind Speed Units, K/M/N Status, A = Data Valid Checksum

OLN

Omega Lane Numbers

obsolete

OSD

Own Ship Data

1 2 3 4 5 6 7 8 9 10 | | | | | | | | | | $--OSD,x.x,A,x.x,a,x.x,a,x.x,x.x,a*hh 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) Heading, degrees true Status, A = Data Valid Vessel Course, degrees True Course Reference Vessel Speed Speed Reference Vessel Set, degrees True Vessel drift (speed) Speed Units Checksum

ROO

Waypoints in Active Route

1 n | | $--ROO,c---c,c---c,....*hh 1) waypoint ID ... n) checksum

RMA

Recommended Minimum Navigation Information

12 1 2 3 4 5 6 7 8 9 10 11| | | | | | | | | | | | | $--RMA,A,llll.ll,a,yyyyy.yy,a,x.x,x.x,x.x,x.x,x.x,a*hh 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) Blink Warning Latitude N or S Longitude E or W Time Difference A, µS Time Difference B, µS Speed Over Ground, Knots Track Made Good, degrees true Magnetic Variation, degrees E or W Checksum

The NMEA 0183 Protocol

14

RMB

Recommended Minimum Navigation Information

14 1 2 3 4 5 6 7 8 9 10 11 12 13| | | | | | | | | | | | | | | $--RMB,A,x.x,a,c--c,c--c,llll.ll,a,yyyyy.yy,a,x.x,x.x,x.x,A*hh 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) Status, V = Navigation receiver warning Cross Track error - nautical miles Direction to Steer, Left or Right TO Waypoint ID FROM Waypoint ID Destination Waypoint Latitude N or S Destination Waypoint Longitude E or W Range to destination in nautical miles Bearing to destination in degrees True Destination closing velocity in knots Arrival Status, A = Arrival Circle Entered Checksum

RMC

Recommended Minimum Navigation Information

12 1 2 3 4 5 6 7 8 9 10 11| | | | | | | | | | | | | $--RMC,hhmmss.ss,A,llll.ll,a,yyyyy.yy,a,x.x,x.x,xxxx,x.x,a*hh 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) Time (UTC) Status, V = Navigation receiver warning Latitude N or S Longitude E or W Speed over ground, knots Track made good, degrees true Date, ddmmyy Magnetic Variation, degrees E or W Checksum

ROT

Rate Of Turn

1 2 3 | | | $--ROT,x.x,A*hh 1) Rate Of Turn, degrees per minute, "-" means bow turns to port 2) Status, A means data is valid 3) Checksum

RPM

Revolutions

1 2 3 4 5 6 | | | | | | $--RPM,a,x,x.x,x.x,A*hh 1) 2) 3) 4) 5) 6) Source; S = Shaft, E = Engine Engine or shaft number Speed, Revolutions per minute Propeller pitch, % of maximum, "-" means astern Status, A means data is valid Checksum

The NMEA 0183 Protocol

15

RSA

Rudder Sensor Angle

1 2 3 4 5 | | | | | $--RSA,x.x,A,x.x,A*hh 1) 2) 3) 4) 5) Starboard (or single) rudder sensor, "-" means Turn To Port Status, A means data is valid Port rudder sensor Status, A means data is valid Checksum

RSD

RADAR System Data

14 1 2 3 4 5 6 7 8 9 10 11 12 13| | | | | | | | | | | | | | | $--RSD,x.x,x.x,x.x,x.x,x.x,x.x,x.x,x.x,x.x,x.x,x.x,a,a*hh 9) 10) 11) 12) 14) Cursor Range From Own Ship Cursor Bearing Degrees Clockwise From Zero Range Scale Range Units Checksum

RTE

Routes

1 2 3 4 5 x n | | | | | | | $--RTE,x.x,x.x,a,c--c,c--c, ..... c--c*hh 1) Total number of messages being transmitted 2) Message Number 3) Message mode c = complete route, all waypoints w = working route, the waypoint you just left, the waypoint you're heading to, then all the rest 4) Waypoint ID x) More Waypoints n) Checksum

SFI

Scanning Frequency Information

1 2 3 4 n | | | | | $--SFI,x.x,x.x,xxxxxx,c .......... xxxxxx,c*hh 1) 2) 3) 4) n) Total Number Of Messages Message Number Frequency 1 Mode 1 Checksum

STN

Multiple Data ID

1 2 | | $--STN,x.x,*hh 1) Talker ID Number 2) Checksum

The NMEA 0183 Protocol

16

TLL

Target Latitude and Longitude

Format unknown

TRF

TRANSIT Fix Data

obsolete

TTM

Tracked Target Message

11 13 1 2 3 4 5 6 7 8 9 10| 12| 14 | | | | | | | | | | | | | | $--TTM,xx,x.x,x.x,a,x.x,x.x,a,x.x,x.x,a,c--c,a,a*hh 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) Target Number Target Distance Bearing from own ship Bearing Units Target speed Target Course Course Units Distance of closest-point-of-approach Time until closest-point-of-approach "-" means increasing "-" means increasing Target name Target Status Reference Target Checksum

VBW

Dual Ground/Water Speed

1 2 3 4 5 6 7 | | | | | | | $--VBW,x.x,x.x,A,x.x,x.x,A*hh 1) 2) 3) 4) 5) 6) 7) Longitudinal water speed, "-" means astern Transverse water speed, "-" means port Status, A = data valid Longitudinal ground speed, "-" means astern Transverse ground speed, "-" means port Status, A = data valid Checksum

VDR

Set and Drift

1 2 3 4 5 6 7 | | | | | | | $--VDR,x.x,T,x.x,M,x.x,N*hh 1) 2) 3) 4) 5) 6) 7) Degress True T = True Degrees Magnetic M = Magnetic Knots (speed of current) N = Knots Checksum

The NMEA 0183 Protocol

17

VHW

Water Speed and Heading

1 2 3 4 5 6 7 8 9 | | | | | | | | | $--VHW,x.x,T,x.x,M,x.x,N,x.x,K*hh 1) 2) 3) 4) 5) 6) 7) 8) 9) Degress True T = True Degrees Magnetic M = Magnetic Knots (speed of vessel relative to the water) N = Knots Kilometers (speed of vessel relative to the water) K = Kilometres Checksum

VLW

Distance Traveled through Water

1 2 3 4 5 | | | | | $--VLW,x.x,N,x.x,N*hh 1) 2) 3) 4) 5) Total cumulative distance N = Nautical Miles Distance since Reset N = Nautical Miles Checksum

VPW

Speed – Measured Parallel to Wind

1 2 3 4 5 | | | | | $--VPW,x.x,N,x.x,M*hh 1) 2) 3) 4) 5) Speed, "-" means downwind N = Knots Speed, "-" means downwind M = Meters per second Checksum

VTG

Track Made Good and Ground Speed

1 2 3 4 5 6 7 8 9 | | | | | | | | | $--VTG,x.x,T,x.x,M,x.x,N,x.x,K*hh 1) 2) 3) 4) 5) 6) 7) 8) 9) Track Degrees T = True Track Degrees M = Magnetic Speed Knots N = Knots Speed Kilometers Per Hour K = Kilometres Per Hour Checksum

The NMEA 0183 Protocol

18

VWR

Relative Wind Speed and Angle

1 2 3 4 5 6 7 8 9 | | | | | | | | | $--VWR,x.x,a,x.x,N,x.x,M,x.x,K*hh 1) 2) 3) 4) 5) 6) 7) 8) 9) Wind direction Wind direction Speed N = Knots Speed M = Meters Per Speed K = Kilometers Checksum magnitude in degrees Left/Right of bow

Second Per Hour

WCV

Waypoint Closure Velocity

1 2 3 4 | | | | $--WCV,x.x,N,c--c*hh 1) 2) 3) 4) Velocity N = knots Waypoint ID Checksum

WDC

Distance to Waypoint – Great Circle

Format unknown

WDR

Distance to Waypoint – Rhumb Line

Format unknown

WNC

Distance – Waypoint to Waypoint

1 2 3 4 5 6 7 | | | | | | | $--WNC,x.x,N,x.x,K,c--c,c--c*hh 1) 2) 3) 4) 5) 6) 7) Distance, Nautical Miles N = Nautical Miles Distance, Kilometers K = Kilometers TO Waypoint FROM Waypoint Checksum

WPL

Waypoint Location

1 2 3 4 5 6 | | | | | | $--WPL,llll.ll,a,yyyyy.yy,a,c--c*hh 1) 2) 3) 4) 5) 6) Latitude N or S (North or South) Longitude E or W (East or West) Waypoint Name Checksum

The NMEA 0183 Protocol

19

XDR

Cross Track Error – Dead Reckoning

1 2 3 4 n | | | | | $--XDR,a,x.x,a,c--c, ..... *hh 1) 2) 3) 4) x) n) Transducer type Measurement data Units of measurement Name of transducer More of the same Checksum

XTE

Cross-Track Error – Measured

1 2 3 4 5 6 | | | | | | $--XTE,A,A,x.x,a,N,*hh 1) Status V = LORAN-C blink or SNR warning A = general warning flag or other navigation systems when a reliable fix is not available 2) Status V = Loran-C cycle lock warning flag A = OK or not used 3) Cross track error magnitude 4) Direction to steer, L or R 5) Cross track units. N = Nautical Miles 6) Checksum

XTR

Cross Track Error – Dead Reckoning

1 2 3 4 | | | | $--XTR,x.x,a,N*hh 1) 2) 3) 4) Magnitude of cross track error Direction to steer, L or R Units, N = Nautical Miles Checksum

ZDA

Time & Date – UTC, Day, Month, Year and Local Time Zone

1 2 3 4 5 6 7 | | | | | | | $--ZDA,hhmmss.ss,xx,xx,xxxx,xx,xx*hh 1) 2) 3) 4) 5) 6) 7) Local zone minutes description, same sign as local hours Local zone description, 00 to +/- 13 hours Year Month, 01 to 12 Day, 01 to 31 Time (UTC) Checksum

ZDL

Time and Distance to Variable Point

Format unknown

The NMEA 0183 Protocol

20

ZFO

UTC & Time from Origin Waypoint

1 2 3 4 | | | | $--ZFO,hhmmss.ss,hhmmss.ss,c--c*hh 1) 2) 3) 4) Time (UTC) Elapsed Time Origin Waypoint ID Checksum

ZTG

UTC & Time to Destination Waypoint

1 2 3 4 | | | | $--ZTG,hhmmss.ss,hhmmss.ss,c--c*hh 1) 2) 3) 4) Time (UTC) Time Remaining Destination Waypoint ID Checksum

The NMEA 0183 Protocol

21

6. Some Proprietary Sentences
$PGRMC Sensor Configuration Information
Garmin proprietary sentence 13 14 1 2 3 4 5 6 7 8 9 10| 12| | | | | | | | | | | | | | $PGRMC,A,x.x,hh,x.x,x.x,x.x,x.x,x.x,c,c,2,c*hh 1) Fix mode, A=automatic (only option) 2) Altitude above/below mean sea level, -1500.0 to 18000.0 meters 3) Earth datum index. If the user datum index (96) is specified, fields 5-8 must contain valid values. Otherwise, fields 4-8 must be null. 4) User earth datum semi-major axis, 6360000.0 to 6380000.0 meters (.001 meters resolution) 5) User earth datum inverse flattening factor, 285.0 to 310.0 (10-9 resolution) 6) User earth datum delta x earth centered coordinate, -5000.0 to 5000.0 meters (1 meter resolution) 7) User earth datum delta y earth centered coordinate, -5000.0 to 5000.0 meters (1 meter resolution) 8) User earth datum delta z earth centered coordinate, -5000.0 to 5000.0 meters (1 meter resolution) 9) Differential mode, A = automatic (output DGPS data when available, non-DGPs otherwise), D = differential exclusively (output only differential fixes) 10) NMEA Baud rate, 1 = 1200, 2 = 2400, 3 = 4800, 4 = 9600 11) Filter mode, 2 = no filtering (only option) 12) PPS mode, 1 = No PPS, 2 = 1 Hz 13) Checksum

$PGRME Estimated Position Error
Garmin proprietary sentence 1 2 3 4 5 6 7 | | | | | | | $PGRME,x.x,M,x.x,M,x.x,M*hh 1) 2) 3) 4) 5) 6) 7) Estimated horizontal position error (HPE) Unit, metres Estimated vertical error (VPE) Unit, metres Overall spherical equivalent position error Unit, metres Checksum

The NMEA 0183 Protocol

22

$PGRMF Position Fix Sentence
Garmin proprietary sentence 10 12 15 1 2 3 4 5 6 7 8 9 | 11| 13 14| 16 | | | | | | | | | | | | | | | | $PGRMF,x.x,x.x,ddmmyy,hhmmss,x.x,ddmm.mmmm,c,dddmm.mmmm,c,c,c,x.x,x.x,c,c*hh 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) GPS week number (0 - 1023) GPS seconds (0 - 604799) UTC date of position fix UTC time of position fix GPS leap second count Latitude N or S Longitude E or W Mode M = manual A = automatic Fix type 0 = no fix 1 = 2D fix 2 = 3D fix Speed over ground, 0 to 999 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) Checksum

11)

12) 13) 14) 15) 16)

$PGRMI Sensor Initialisation Information
Garmin proprietary sentence 1 2 3 4 5 6 7 | | | | | | | $PGRMI,ddmm.mmm,N,ddmm.mmm,E,ddmmyy,hhmmss*hh 1) 2) 3) 4) 5) 6) 7) Latitude N or S Longitude E or W Current UTC date Current UTC time Checksum

$PGRMM Map Datum
Garmin proprietary sentence 1 2 | | $PGRMM,c---c*hh 1) Currently active horizontal datum (WGS-84, NAD27 Canada, ED50, a.s.o) 2) Checksum

The NMEA 0183 Protocol

23

$PGRMO Output Sentence Enable/Disable
Garmin proprietary sentence 1 2 3 | | | $PGRMO,ccccc,c*hh 1) Target sentence description (e.g., PGRMT, GPGSV, etc.) 2) Target sentence mode 0 = disable specified sentence 1 = enable specified sentence 2 = disable all 3 = enable all output sentences (except GPALM) 3) Checksum

$PGRMT Sensor Status Information
Garmin proprietary sentence 1 2 3 4 5 6 7 8 9 10 | | | | | | | | | | $PGRMT,c...c,c,c,c,c,c,c,x.x,c*hh 1) Product, model and software version e.g. "GPS25VEE] 1.10" 2) Rom checksum test P = pass F = fail 3) Receiver failure discrete P = pass F = fail 4) Stored data lost R = retained L = lost 5) Real time clock lost R = retained L = lost 6) 0scillator drift discrete P = pass F = excessive drift detected 7) Data collection discrete C = collecting null if not collecting 8) Board temperature in degrees C 9) Board configuration data R = retained L = lost 10) Checksum

$PGRMV 3D Velocity
Garmin proprietary sentence 1 2 3 4 | | | | $PGRMV,x.x,x.x,x.x*hh 1) 2) 3) 4) True east velocity, -999.9 to 9999.9 meters/second True north velocity, -999.9 to 9999.9 meters/second Up velocity, -999.9 to 9999.9 meters/second Checksum

The NMEA 0183 Protocol

24

$PGRMZ Altitude Information
Garmin proprietary sentence 1 2 3 4 | | | | $PGRMZ,x.x,f,h*hh 1) Altitude 2) Unit, feets 3) Position fix dimensions 2 user altitude 3 GPS altitude 4) Checksum

$PSLIB

Differental GPS Beacon Receiver Control

Starlink, Inc. proprietary sentence, used by Garmin and others 1 2 3 4 | | | | $PSLIB,x.x,x.x,c*hh 1) Frequency 2) Bit rate 3) Request type J = status request K = configuration request blank = tuning message 4) Checksum

The NMEA 0183 Protocol

25

7. Manufacturer Codes
Note: This list is out-of-date, but perhaps still useful. AAR ACE ACR ACS ACT AGI AHA AIP ALD AMR AMT ANS ANX ANZ APC APN APX AQC AQD AQM ASP ATE ATM ATR ATV AVN AWA BBL BBR BDV BEC BGS BGT BHE BHR BLB BME BNI BNS BRM BRY BTH BTK BTS BXA CAT CBN CCA CCC CCL CCM CDC CEC CHI CKM CMA CMC Asian American Resources Auto-Comm Engineering Corporation ACR Electronics, Inc. Arco Solar, Inc. Advanced Control Technology Airguide Instrument Company Autohelm of America Aiphone Corporation Alden Electronics, Inc. AMR Systems Airmar Technology Antenna Specialists Analytyx Electronic Systems Anschutz of America Apelco American Pioneer, Inc. Amperex, Inc. Aqua-Chem, Inc. Aquadynamics, Inc. Aqua Meter Instrument Company American Solar Power Aetna Engineering Atlantic Marketing Company, Inc. Airtron Activation, Inc. Advanced Navigation, Inc. Awa New Zealand, Limited BBL Industries, Inc. BBR and Associates Brisson Development, Inc. Boat Electric Company Barringer Geoservice Brookes and Gatehouse, Inc. BH Electronics Bahr Technologies, Inc. Bay Laboratories Bartel Marine Electronics Neil Brown Instrument Systems Bowditch Navigation Systems Mel Barr Company Byrd Industries Benthos, Inc. Baltek Corporation Boat Sentry, Inc. Bendix-Avalex, Inc. Catel Cybernet Marine Products Copal Corporation of America Coastal Communications Company Coastal Climate Company Coastal Communications Cordic Company Ceco Communications, Inc. Charles Industries, Limited Cinkel Marine Electronics Industries Societe Nouvelle D'Equiment du Calvados Coe Manufacturing Company

CME CMP CMS CMV CNV CNX CPL CPN CPS CPT CRE CRO CRY CSI CSM CST CSV CTA CTB CTC CTE CTL CNI CWD CWV CYZ DCC DEB DFI DGC DME DMI DNS DNT DPS DRL DSC DYN DYT EBC ECT EEV EFC ELD EMC EMS ENA ENC EPM EPT ERC ESA FDN FHE FJN FMM FNT FRC FTG FUJ FEC

Cushman Electronics, Inc. C-Map, s.r.l. Coastal Marine Sales Company CourseMaster USA, Inc. Coastal Navigator Cynex Manufactoring Company Computrol, Inc. Compunav Columbus Positioning, Inc. CPT, Inc. Crystal Electronics, Limited The Caro Group Crystek Crystals Corporation Communication Systems International, Inc. Comsat Maritime Services Cast, Inc. Combined Services Current Alternatives Cetec Benmar Cell-tech Communications Castle Electronics C-Tech, Limited Continental Instruments Cubic Western Data Celwave R.F., Inc. cYz, Inc. Dolphin Components Corporation Debeg GmbH Defender Industries, Inc. Digicourse, Inc. Digital Marine Electronics Corp. Datamarine International, Inc. Dornier System GmbH Del Norte Technology, Inc. Danaplus, Inc. R.L. Drake Company Dynascan Corporation Dynamote Corporation Dytek Laboratories, Inc. Emergency Beacon Corporation Echotec, Inc. EEV, Inc. Efcom Communication Systems Electronic Devices, Inc. Electric Motion Company Electro Marine Systems, Inc. Energy Analysts, Inc. Encron, Inc. Epsco Marine Eastprint, Inc. The Ericsson Corporation European Space Agency Fluiddyne Fish Hawk Electronics Jon Fluke Company First Mate Marine Autopilots Franklin Net and Twine, Limited The Fredericks Company T.G. Faria Corporation Fujitsu Ten Corporation of America Furuno Electric Company (??)

The NMEA 0183 Protocol

26

FUR GAM GCA GES GFC GIS GPI GRM GSC GTO GVE GVT HAL HAR HIG HIT HPK HRC HRT HTI HUL HWM ICO IFD IFI IME IMI IMM IMP IMT INM INT IRT IST ITM ITR JAN JFR JMT JRC JRI JTC JTR KBE KBM KLA KMR KNG KOD KRP KVH KYI LAT LEC LMM LRD LSE LSP LTF LWR MCL

Furuno USA, Inc. GRE America, Inc. Gulf Cellular Associates Geostar Corporation Graphic Controls Corporation Galax Integrated Systems Global Positioning Instrument Corporation Garmin Corporation Gold Star Company, Limited Gro Electronics Guest Corporation Great Valley Technology HAL Communications Corporation Harris Corporation Hy-Gain Hi-Tec Hewlett-Packard Harco Manufacturing Company Hart Systems, Inc. Heart Interface, Inc. Hull Electronics Company Honeywell Marine Systems Icom of America, Inc. International Fishing Devices Instruments for Industry Imperial Marine Equipment I.M.I. ITT MacKay Marine Impulse Manufacturing, Inc. International Marketing and Trading, Inc. Inmar Electronic and Sales, Inc. Intech, Inc. Intera Technologies, Ltd. Innerspace Technology, Inc. Intermarine Electronics, Inc. Itera, Limited Jan Crystals Ray Jefferson Japan Marine Telecommunications Japan Radio Company, Inc. J-R Industries, Inc. J-Tech Associates, Inc. Jotron Radiosearch, Ltd. KB Electronics, Ld. Kennebec Marine Company Klein Associates, Inc. King Marine Radio Corporation King Radio Corporation Koden Electronics Company, Ltd. Krupp International, Inc. KVH Company Kyocera International, Inc. Latitude Corporation Lorain Electronics Corporation Lamarche Manufacturing Company Lorad Littlemore Scientific Engineering Laser Plot, Inc. Littlefuse, Inc. Lowrance Electronics Corportation Micrologic, Inc.

MDL MEC MEG MFR MFW MGN MGS MIE MIM MLE MLN MLP MLT MMB MME MMP MMS MNI MNT MNX MOT MPN MQS MRC MRE MRP MRR MRS MSB MSE MSM MST MTA MTG MTK MTR MTS MUR MVX MXX MES NAT NEF NMR NGS NOM NOV NSM NTK NVC NVS NVO OAR ODE ODN OIN OKI OLY OMN ORE

Medallion Instruments, Inc. Marine Engine Center, Inc. Maritec Engineering GmbH Modern Products, Ltd Frank W. Murphy Manufacturing Magellan Corporation MG Electronic Sales Corporation Mieco, Inc. Marconi International Marine Company Martha Lake Electronics Matlin Company Marlin Products Miller Technologies Marsh-McBirney, Inc. Marks Marine Engineering Metal Marine Pilot, Inc. Mars Marine Systems Micro-Now Instrument Company Marine Technology Marinex Motorola Memphis Net and Twine Company, Inc. Marquis Industries, Inc. Marinecomp, Inc. Morad Electronics Corporation Mooring Products of New England II Morrow, Inc. Marine Radio Service Mitsubishi Electric Company, Ltd. Master Electronics Master Mariner, Inc. Mesotech Systems, Ltd. Marine Technical Associates Narine Technical Assistance Group Martech, Inc. Mitre Corporation, Inc. Mets, Inc. Murata Erie North America Magnavox Advanced Products and Systems Company Maxxima Marine Marine Electronics Service, Inc. Nautech, Limited New England Fishing Gear, Inc. Newmar Navigation Sciences, Inc. Nav-Com, Inc. NovAtel Communications, Ltd. Northstar Marine Novatech Designs, Ltd. Navico Navstar Navionics, s.p.a. O.A.R. Corporation Ocean Data Equipment Corporation Odin Electronics, Inc. Ocean instruments, Inc. Oki Electronic Industry Company Navstar Limited (Polytechnic Electronics) Omnetics Ocean Research

The NMEA 0183 Protocol

27

OTK PCE PDM PLA PLI PMI PMP PRK PSM PTC PTG PTH RAC RAE RAY RCA RCH RCI RDI RDM REC RFP RGC RGY RMR RSL RSM RWI RME RTN SAI SBR SCR SEA SEC SEP SFN SGC SIG SIM SKA SKP SLI SME SMF SML SMI SNV SOM SOV SPL SPT SRD SRS SRT SSI STC STI STM SVY SWI

Ocean Technology Pace Prodelco Marine Systems Plath, C. Division of Litton Pilot Instruments Pernicka Marine Products Pacific Marine Products Perko, Inc. Pearce-Simpson Petro-Com P.T.I./Guest Pathcom, Inc. Racal Marine, Inc. RCA Astro-Electronics Raytheon Marine Company RCA Service Company Roach Engineering Rochester Instruments, Inc. Radar Devices Ray-Dar Manufacturing Company Ross Engineering Company Rolfite Products, Inc. RCS Global Communications, Inc. Regency Electronics, Inc. RCA Missile and Surface Radar Ross Laboratories, Inc. Robertson-Shipmate, USA Rockwell International Racal Marine Electronics Robertson Tritech Nyaskaien A/S SAIT, Inc. Sea-Bird electronics, Inc. Signalcrafters, Inc. SEA Sercel Electronics of Canada Steel and Engine Products, Inc. Seafarer Navigation International SGC, Inc. Signet, Inc. Simrad,Inc Skantek Corporation Skipper Electronics A/S Starlink, Inc. Shakespeare Marine Electronics Seattle Marine and Fishing Supply Co. Simerl Instruments Sperry Marine, Inc. Starnav Corporation Sound Marine Electronics, Inc. Sell Overseas America Spelmar Sound Powered Telephone SRD Labs Scientific Radio Systems, Inc. Standard Radio and Telefon AB Sea Scout Industries Standard Communications Sea-Temp Instrument Corporation Si-Tex Marine Electronics Savoy Electronics Swoffer Marine Instruments, Inc.

SRS TBB TCN TDL THR TLS TMT TNL TRC TSI TTK TTS TWC TXI UME UNI UNP UNF VAN VAR VCM VEX VIS VMR WAL WBG WEC WHA WMM WMR WNG WSE WTC WST YAS

Shipmate, Rauff & Sorensen, A/S Thompson Brothers Boat Manufacturing Company Trade Commission of Norway (THE) Tideland Signal Thrane and Thrane A/A Telesystems Tamtech, Ltd. Trimble Navigation Tracor, Inc. Techsonic Industries, Inc. Talon Technology Corporation Transtector Systems Transworld Communications, Inc. Texas Instruments, Inc. Umec Uniden Corporation of America Unipas, Inc. Uniforce Electronics Company Vanner, Inc. Varian Eimac Associates Videocom Vexillar Vessel Information Systems, Inc. Vast Marketing Corporation Walport USA Westberg Manufacturing, Inc. Westinghouse Electric Corporation W-H Autopilots Wait Manufacturing and Marine Sales Company Wesmar Electronics Winegard Company Wilson Electronics Corporation Watercom West Electronics Ltd. Yaesu Electronics

The NMEA 0183 Protocol

28

8. References
[1] [2] [3] [4] National Marine Electronics Association: http://www.nmea.org Torsten Baumbach's web site: http://pandora.inf.uni-jena.de/ttbb/ Peter Bennett’s GPS and NMEA site: http://vancouver-webpages.com/pub/peter/index.html Data Transmission Protocol Specification for Magellan Products. Revision 1.0. Magellan Corporation, Santa Clara 1999. Available at: http://magellangps.com This document describes the protocol used by Magellan’s consumer GPS units, including a number of NMEA 0183 proprietary sentences. [5] SBA-1 Interfacing Manual. Revision 0.0. Communications Systems International, Inc, Calgary, 1999. Available at: www.csi-dgps.com. This manual explains the interfacing of the SBA-1 DGPS beacon receiver to numerous GPS units as well as the CSI proprietary sentences used.