3D Software Box

NMEA 0183 protocol


NMEA 0183 = National Marine Electronics Association protocol 0183

NMEA 0183 is a protocol most commonly used to send information from GPS receivers today.

Physical layer

Usually a RS232 (V.24) serial connection.

Link layer


Total message is maximum 82 characters, including '$' and CR+LF.

Proprietary Extension Message format

Byte posLengthValueDescription
010x24 '$'Start character
110x50 'P'Type: Proprietary
23Manufacturer ID
5Message Data

Talker Message format

Byte posLengthValueDescription
010x24 '$'Start character
12Talker ID
33Message Type
6Message Data (comma separated parameters)
..10x2a '*'Separator
..2Checksum (optional, omit separator above also)
..10x0d CRStop character
..10x0a LFStop character

Query Message format

Byte posLengthValueDescription
010x24 '$'Start character
12Talker ID (of requester)
32Talker ID (of listener)
510x4f 'Q'Message Type
610x2c ','Separator
7Messages Requested Data (comma separated)
..10x2a '*'Separator
..2Checksum (optional, omit separator above also)
..10x0d CRStop character
..10x0a LFStop character

Talker ID

AGAutopilot - General
APAutopilot - Magnetic
CCComputer - Programmed Calculator (outdated)
CDCommunications - Digital Selective Calling (DSC)
CMComputer - Memory Data (outdated)
CSCommunications - Satellite
CTCommunications - Radio-Telephone (MF/HF)
CVCommunications - Radio-Telephone (VHF)
CXCommunications - Scanning Receiver
DEDECCA Navigation (outdated)
DFDirection Finder
ECElectronic Chart Display & Information System (ECDIS)
EPEmergency Position Indicating Beacon (EPIRB)
EREngine Room Monitoring Systems
GPGlobal Positioning System (GPS)
HCHeading - Magnetic Compass
HEHeading - North Seeking Gyro
HNHeading - Non North Seeking Gyro
IIIntegrated Instrumentation
INIntegrated Navigation
LALoran A (outdated)
LCLoran C
MPMicrowave Positioning System (outdated)
OMOMEGA Navigation System (outdated)
OSDistress Alarm System (outdated)
SDSounder, Depth
SNElectronic Positioning System, other/general
SSSounder, Scanning
TITurn Rate Indicator
TRTRANSIT Navigation System
VDVelocity Sensor, Doppler, other/general
DMVelocity Sensor, Speed Log, Water, Magnetic
VWVelocity Sensor, Speed Log, Water, Mechanical
WIWeather Instruments
YCTransducer - Temperature (outdated)
YDTransducer - Displacement, Angular or Linear (outdated)
YFTransducer - Frequency (outdated)
YLTransducer - Level (outdated)
YPTransducer - Pressure (outdated)
YRTransducer - Flow Rate (outdated)
YTTransducer - Tachometer (outdated)
YVTransducer - Volume (outdated)
YX Transducer
ZATimekeeper - Atomic Clock
ZCTimekeeper - Chronometer
ZQTimekeeper - Quartz
ZVTimekeeper - Radio Update, WWV or WWVH

Message Type

AAMWaypoint Arrival Alarm
ALMGPS Almanac Data
APAAutopilot Sentence "A"
APBAutopilot Sentence "B"
ASDAutopilot System Data
BODBearing - Waypoint to Waypoint
BWCBearing and Distance to Waypoint - Great Circle
BWRBearing and Distance to Waypoint - Rhumb Line
BWWBearing - Waypoint to Waypoint
DBKDepth Below Keel
DBSDepth Below Surface
DBTDepth below transducer
DCNDecca Position
DPTDepth of Water
DSCDigital Selective Calling Information
DSEExtended DSC
DSIDSC Transponder Initiate
DSRDSC Transponder Response
DTMDatum Reference
FSIFrequency Set Information
GBSGPS Satellite Fault Detection
GGAGlobal Positioning System Fix Data
GLCGeographic Position, Loran-C
GLLGeographic Position - Latitude/Longitude
GRSGPS Range Residuals
GSAGPS DOP and active satellites
GSTGPS Pseudorange Noise Statistics
GSVSatellites in view
GTDGeographic Location in Time Differences
GXATRANSIT Position - Latitude/Longitude
HDGHeading - Deviation & Variation
HDMHeading - Magnetic
HDTHeading - True
HFBTrawl Headrope to Footrope and Bottom
HSCHeading Steering Command
ITSTrawl Door Spread 2 Distance
LCDLoran-C Signal Data
MSKControl for a Beacon Receiver
MSSBeacon Receiver Status
MTWMean Temperature of Water
MWDWind Direction & Speed
MWVWind Speed and Angle
OLNOmega Lane Numbers
OSDOwn Ship Data
R00Waypoints in active route
RMARecommended Minimum Navigation Information
RMBRecommended Minimum Navigation Information
RMCRecommended Minimum Navigation Information
ROTRate Of Turn
RSARudder Sensor Angle
RSDRADAR System Data
SFIScanning Frequency Information
STNMultiple Data ID
TDSTrawl Door Spread Distance
TFITrawl Filling Indicator
TLLTarget Latitude and Longitude
TPCTrawl Position Cartesian Coordinates
TPRTrawl Position Relative Vessel
TPTTrawl Position True
TTMTracked Target Message
VBWDual Ground/Water Speed
VDRSet and Drift
VHWWater speed and heading
VLWDistance Traveled through Water
VPWSpeed - Measured Parallel to Wind
VTGTrack made good and Ground speed
VWRRelative Wind Speed and Angle
WCVWaypoint Closure Velocity
WDCDistance to Waypoint - Great Circle
WDRDistance to Waypoint - Rhumb Line
WNCDistance - Waypoint to Waypoint
WPLWaypoint Location
XDRCross Track Error - Dead Reckoning
XTECross-Track Error, Measured
XTRCross Track Error - Dead Reckoning
ZDATime & Date - UTC, day, month, year and local time zone
ZDLTime and Distance to Variable Point
ZFOUTC & Time from origin Waypoint
ZTGUTC & Time to Destination Waypoint

Manufacturer ID

3SN3-S Navigation
AARAsian American Resources
ACEAuto-Comm Engineering Corporation
ACRACR Electronics, Inc.
ACSArco Solar, Inc.
ACTAdvanced Control Technology
AGIAirguide Instrument Company
AHAAutohelm of America
AIPAiphone Corporation
ALDAlden Electronics, Inc.
AMCAlltek Marine Electronics Corp.
AMIAdvanced Marine Instrumentation, Ltd.
AMRAMR Systems
AMTAirmar Technology
ANDAndrew Corporation
ANSAntenna Specialists
ANXAnalytyx Electronic Systems
ANZAnschutz of America
APNAmerican Pioneer, Inc.
APWAutomatic Power, Inc. / Pharos Marine
APXAmperex, Inc.
AQCAqua-Chem, Inc.
AQDAquadynamics, Inc.
AQMAqua Meter Instrument Company
ARLActive Research Limited
ASPAmerican Solar Power
ATCAdvanced C Technology, Ltd
ATEAetna Engineering
ATMAtlantic Marketing Company, Inc.
ATVActivation, Inc.
AVNAdvanced Navigation, Inc.
AWAAwa New Zealand, Limited
AXNAxiom Navigation, Inc.
BBLBBL Industries, Inc.
BBRBBR and Associates
BDVBrisson Development, Inc.
BECBoat Electric Company
BGGBodensee Graavitymeter Geosystems GmbH
BGSBarringer Geoservice
BGTBrookes and Gatehouse, Inc.
BHEBH Electronics
BHRBahr Technologies, Inc.
BLBBay Laboratories
BMEBartel Marine Electronics
BMTBosch Rexroth Ag Marine Technique
BNINeil Brown Instrument Systems
BNSBowditch Navigation Systems
BRMMel Barr Company
BROBroadgate, Ltd
BRYByrd Industries
BTHBenthos, Inc.
BTKBaltek Corporation
BTSBoat Sentry, Inc.
BVEBv Engineering
BXABendix-Avalex, Inc.
CAICambridge Aero Instruments
CBNCybernet Marine Products
CCACopal Corporation of America
CCCCoastal Communications Company
CCLCoastal Climate Company
CCMCoastal Communications
CDCCordic Company
CECCeco Communications, Inc.
CEICambridge Engineering, Inc.
CHICharles Industries, Ltd.
CKMCinkel Marine Electronics Industries
CMASociete Nouvelle D'Equiment du Calvados
CMCCoe Manufacturing Company
CMECushman Electronics, Inc.
CMLCml Microsystems, PLC
CMNComnav Marine, Ltd.
CMPC-Map, s.r.l.
CMSCoastal Marine Sales Company
CMVCourseMaster USA, Inc.
CNIContinental Instruments
CNSC.N.S. Systems AB
CNVCoastal Navigator
CNXCynex Manufactoring Company
CPLComputrol, Inc.
CPSColumbus Positioning, Inc.
CRECrystal Electronics, Limited
CROThe Caro Group
CRYCrystek Crystals Corporation
CSICommunication Systems International, Inc.
CSMComsat Maritime Services
CSRCsr Stockholm
CSTCast, Inc.
CSVCombined Services
CTACurrent Alternatives
CTBCetec Benmar
CTCCell-tech Communications
CTECastle Electronics
CTLC-Tech, Limited
CTSC-Tech Systems
CWDCubic Western Data
CWVCelwave R.F., Inc.
CYZcYz, Inc.
DASDassault Sercel Navigation-Positioning
DBMDeep Blue Marine
DCCDolphin Components Corporation
DEBDebeg GmbH
DECDecca Division, Litton Marine Systems, Bv
DFIDefender Industries, Inc.
DGCDigicourse, Inc.
DMEDigital Marine Electronics Corp.
DMIDatamarine International, Inc.
DNSDornier System GmbH
DNTDel Norte Technology, Inc.
DOIDigital Oaceans Inc.
DPSDanaplus, Inc.
DRLR.L. Drake Company
DSCDynascan Corporation
DTNDytechna, Ltd
DYNDynamote Corporation
DYTDytek Laboratories, Inc.
EANEuro Avionics Navigationssysteme Gmbh
EBCEmergency Beacon Corporation
ECTEchotec, Inc.
EDOEdo Corporation Electroacoustics Div.
EFCEfcom Communication Systems
EKCEastman Kodak
ELAAllied Signal Elac Nautik
ELDElectronic Devices, Inc.
EMCElectric Motion Company
EMSElectro Marine Systems, Inc.
ENAEnergy Analysts, Inc.
ENCEncron, Inc.
EPMEpsco Marine
EPTEastprint, Inc.
ERCThe Ericsson Corporation
ESAEuropean Space Agency
ESCElectronics Emporium, Division Of Esc Products
ESYE-Systems, Eci Division
FECFuruno Electric Company
FHEFish Hawk Electronics
FJNJon Fluke Company
FLAFlarm Technolgy
FLOFloscan Incorporated
FMMFirst Mate Marine Autopilots
FNTFranklin Net and Twine, Limited
FRCThe Fredericks Company
FSTFastrax Oy
FTGT.G. Faria Corporation
FUJFujitsu Ten Corporation of America
FURFuruno USA, Inc.
GAMGRE America, Inc.
GCAGulf Cellular Associates
GECGec Plessey Semiconductors
GESGeostar Corporation
GFCGraphic Controls Corporation
GFVGfv Marine Ltd.
GISGalax Integrated Systems
GNVGeonav International
GPIGlobal Positioning Instrument Corporation
GPRGlobal Positioning System Joint Program Office (Rockwell Collins)
GRMGarmin Corporation
GSCGold Star Company, Limited
GTIGenesis Technology International Ltd
GTOGro Electronics
GVEGuest Corporation
GVTGreat Valley Technology
HAIHydragraphic Associates, Ltd
HALHAL Communications Corporation
HARHarris Corporation
HILPhilips Navigation A/S
HMSHyde Marine Systems, Inc.
HRCHarco Manufacturing Company
HRTHart Systems, Inc.
HTIHeart Interface, Inc.
HULHull Electronics Company
HWMHoneywell Marine Systems
IBMIbm Microelectronics
ICGInitiative Computing Usa, Inc. Initiative Computing Ag
ICOIcom of America, Inc.
IFDInternational Fishing Devices
IFIInstruments for Industry
IMEImperial Marine Equipment
IMIInternational Marine Instruments
IMMITT MacKay Marine
IMPImpulse Manufacturing, Inc.
IMRIdeal Technologies Inc
IMTInternational Marketing and Trading, Inc.
INMInmar Electronic and Sales, Inc.
INTIntech, Inc.
IRTIntera Technologies, Ltd.
ISTInnerspace Technology, Inc.
ITMIntermarine Electronics, Inc.
ITRItera, Limited
IWWInland Waterways (Germany)
JANJan Crystals
JASJasco Research Ltd.
JFRRay Jefferson
JMTJapan Marine Telecommunications
JRCJapan Radio Company, Inc.
JRIJ-R Industries, Inc.
JTCJ-Tech Associates, Inc.
JTRJotron Radiosearch, Ltd.
KBEKB Electronics, Ltd.
KBMKennebec Marine Company
KELKnudsen Engineering, Ltd
KHUKelvin Hughes Ltd
KLAKlein Associates, Inc.
KMEKyushu Matsushita Electric
KMRKing Marine Radio Corporation
KNCKongsberg Norcontrols
KNGKing Radio Corporation
KODKoden Electronics Company, Ltd.
KRPKrupp International, Inc.
KSTKongsberg Seatex A/S
KVHKVH Company
KYIKyocera International, Inc.
L3AL3 Communications Recorders Division
LATLatitude Corporation
LCILasercraft Inc.
LECLorain Electronics Corporation
LITLitton Laser Systems
LMMLamarche Manufacturing Company
LSELittlemore Scientific Engineering
LSPLaser Plot, Inc.
LSTLite Systems Engineering
LTFLittlefuse, Inc.
LTILaser Technology, Inc.
LWRLowrance Electronics Corportation
MCACanadian Marconi Company
MCIMatsushita Communications
MCLMicrologic, Inc.
MDLMedallion Instruments, Inc.
MDSMarine Data Systems
MECMarine Engine Center, Inc.
MEGMaritec Engineering GmbH
MESMarine Electronics Service, Inc.
MEWMatsushita Electric Works
MFRModern Products, Ltd
MFWFrank W. Murphy Manufacturing
MGNMagellan Corporation
MGSMG Electronic Sales Corporation
MIEMieco, Inc.
MIMMarconi International Marine Company
MLEMartha Lake Electronics
MLNMatlin Company
MLPMarlin Products
MLTMiller Technologies
MMBMarsh-McBirney, Inc.
MMEMarks Marine Engineering
MMPMetal Marine Pilot, Inc.
MMSMars Marine Systems
MMTMicro Modular Technologies
MNIMicro-Now Instrument Company
MNTMarine Technology
MPIMegapulse, Inc.
MPNMemphis Net and Twine Company, Inc.
MQSMarquis Industries, Inc.
MRCMarinecomp, Inc.
MREMorad Electronics Corporation
MRPMooring Products of New England
MRRII Morrow, Inc.
MRSMarine Radio Service
MSBMitsubishi Electric Company, Ltd.
MSEMaster Electronics
MSFMicrosoft Corporation
MSMMaster Mariner, Inc.
MSTMesotech Systems, Ltd.
MTAMarine Technical Associates
MTDMaritel Data Services
MTGNarine Technical Assistance Group
MTIMobile Telesystems, Inc.
MTKMartech, Inc.
MTRMitre Corporation, Inc.
MTSMets, Inc.
MURMurata Erie North America
MVXMagnavox Advanced Products and Systems Company
MXXMaxxima Marine
NATNautech, Limited
NAVNavtec, Incorporated
NEFNew England Fishing Gear, Inc.
NGSNavigation Sciences, Inc.
NOMNav-Com, Inc.
NORNortech Surveys (Canada)
NOVNovAtel Communications, Ltd.
NSMNorthstar Marine
NTINorthstar Technologies, Inc.
NTKNovatech Designs, Ltd.
NTSNavtech Systems
NUTNautitech Pty, Ltd
NVONavionics, s.p.a.
NWCNaval Warfare Center
OARO.A.R. Corporation
ODEOcean Data Equipment Corporation
ODNOdin Electronics, Inc.
OHBOHB Systems
OINOcean instruments, Inc.
OKIOki Electronic Industry Company
OLYNavstar Limited (Polytechnic Electronics)
OMTOmnitech A/Ss
OREOcean Research
OSIOffshore Systems Intl.
OSLOffshore Systems, Ltd.
OTKOcean Technology
PCMpSea Marine Systems
PDMProdelco Marine Systems
PLAPlath, C. Division of Litton
PLIPilot Instruments
PMIPernicka Marine Products
PMPPacific Marine Products
PNLPoints North, Ltd
PRKPerko, Inc.
PSTPointstar A/S
PTHPathcom, Inc.
RACRacal Marine, Inc.
RAERCA Astro-Electronics
RAYRaytheon Marine Company
RCARCA Service Company
RCHRoach Engineering
RCIRochester Instruments, Inc.
RDIRadar Devices
RDMRay-Dar Manufacturing Company
RECRoss Engineering Company
RFPRolfite Products, Inc.
RGCRCS Global Communications, Inc.
RGLRiegl Laser Measurement Systems
RGYRegency Electronics, Inc.
RMERacal Marine Electronics
RMRRCA Missile and Surface Radar
RSLRoss Laboratories, Inc.
RSMRobertson-Shipmate, USA
RTNRobertson Tritech Nyaskaien A/S
RWIRockwell International
SAEStn Atlas Elektronic GmbH
SAJSaj Instrument Ab
SALConsilium Marine AB
SAPSystems Engineering & Assessment, Ltd
SBRSea-Bird electronics, Inc.
SCLSokkia Company, Ltd
SCOSimoco Telecommunications Ltd
SCRSignalcrafters, Inc.
SECSercel Electronics of Canada
SEPSteel and Engine Products, Inc.
SERSercel France
SFNSeafarer Navigation International
SIGSignet, Inc.
SKASkantek Corporation
SKPSkipper Electronics A/S
SLIStarlink, Inc.
SMEShakespeare Marine Electronics
SMFSeattle Marine and Fishing Supply Co.
SMISperry Marine, Inc.
SMLSimerl Instruments
SNPScience Applications International Corp
SNVStarnav Corporation
SNYSony Corporation Mobile Electronics
SOMSound Marine Electronics, Inc.
SONSonardyne International Ltd
SOVSell Overseas America
SPTSound Powered Telephone
SRFSirf Technology, Inc.
SRSScientific Radio Systems, Inc.
SRTStandard Radio and Telefon AB
SSCSwedish Space Corporation
SSESeven Star Electronics
SSISea Scout Industries
STCStandard Communications
STISea-Temp Instrument Corporation
STLStreamline Technology, Ltd
STMSi-Tex Marine Electronics
STOStowe Marine Electronics
STTSaab Transpondertech AB
SVYSavoy Electronics
SWISwoffer Marine Instruments, Inc.
TBBThompson Brothers Boat Manufacturing Company
TCNTrade Commission of Norway (THE)
TDLTideland Signal
TELPlessey Tellumat
THRThrane and Thrane A/A
TMTTamtech, Ltd.
TNLTrimble Navigation
TOPTopcon Positioning Systems, Inc.
TRCTracor, Inc.
TRSTravroute Software
TSITechsonic Industries, Inc.
TTKTalon Technology Corporation
TTSTranstector Systems
TWCTransworld Communications, Inc.
TXITexas Instruments, Inc.
UELUltra Electronics Ltd
UNFUniforce Electronics Company
UNIUniden Corporation of America
UNPUnipas, Inc.
VANVanner, Inc.
VARVarian Eimac Associates
VISVessel Information Systems, Inc.
VMRVast Marketing Corporation
WALWalport USA
WBGWestberg Manufacturing, Inc.
WBRWesbar Corporation
WECWestinghouse Electric Corporation
WHAW-H Autopilots
WMMWait Manufacturing and Marine Sales Company
WMRWesmar Electronics
WNGWinegard Company
WSEWilson Electronics Corporation
WSTWest Electronics Ltd.
YASYaesu Electronics

Typical messages

GGA - Global Positioning System Fixed Data

ParameterName Example Unit Description
1 UTC Time 161229.487 hhmmss.sss
2 Latitude 3723.2475 ddmm.mmmm (degrees + minutes)
3 N/S indicator N N=north or S=south
4 Longitude 12158.3416 dddmm.mmmm (degrees + minutes)
5 E/W indicator W E=east or W=west
6 Position fix indicator 1 0: Fix not available or invalid
1: GPS SPS Mode, fix valid
2: Differential GPS, SPS Mode, fix valid
3: GPS PPS Mode, fix valid
6: Dead Reckoning Mode, fix valid (NMEA 2.3 or higher)
7 Satellites used 07 Range: 0-12
8 HDOP 1.0 Horizontal Dilution of Precision
9 MSL altitude 9.0 meters Altitude above mean sea level
10 Unit M M=meters
11 Geoid separation meters
12 Unit M M=meters
13 Age of diff. corr. seconds Or null if DGPS is not used
14 Diff. ref. station id 0000

Example: $GPGGA, 161229.487,3723.2475,N,12158.3416,W,1,07,1.0,9.0,M,,,,0000*18

GLL - Geographic Position Latitude/Longitude

ParameterName Example Unit Description
1 Latitude 3723.2475 ddmm.mmmm
2 N/S indicator N N=north or S=south
3 Longitude 12158.3416 dddmm.mmmm
4 E/W indicator W E=east or W=west
5 UTC Time 161229.487 hhmmss.sss
6 Status A A: Data is valid
V: Data is not valid
7 Mode A (NMEA 3.0 or higher)
A: Autonomous

Example: $GPGLL,3723.2475,N,12158.3416,W,161229.487,A,A*41

GSA - GNSS DOP and Active Satellites

ParameterName Example Unit Description
1 Mode 1 1: Fix is not available
2: 2D (<4 SV's used)
3: 3D (>3 SV's used)
2 Mode 2 M: Manual - forced to operate in 2D or 3D mode
A: Automatic - allowed to automatically switch 2D/3D
3 Satellite in solution, ch 1 07 Sv on Channel 1
4 Satellite in solution, ch 2 02 Sv on Channel 2
5 Satellite in solution, ch 3 Sv on Channel 3
6 Satellite in solution, ch 4 Sv on Channel 4
7 Satellite in solution, ch 5 Sv on Channel 5
8 Satellite in solution, ch 6 Sv on Channel 6
9 Satellite in solution, ch 7 Sv on Channel 7
10 Satellite in solution, ch 8 Sv on Channel 8
11 Satellite in solution, ch 9 Sv on Channel 9
12 Satellite in solution, ch 10 Sv on Channel 10
13 Satellite in solution, ch 11 Sv on Channel 11
14 Satellite in solution, ch 12 Sv on Channel 12
15 PDOP 1.8 Position Dilution of Precision
16 HDOP 1.0 Horizontal Dilution of Precision
17 VDOP 1.5 Vertical Dilution of Precision

Example: $GPGSA,A,3,07,02,26,27,09,04,15,,,,,,1.8,1.0,1.5*33

GSV - GNSS Satellites in View

ParameterName Example Unit Range Description
1 Number of messages 1-3
2 Message number 1-3
3 Satellites in view 07
4 Channel 1: Satelitte ID 07 1-32 Range: 1-32
5 Channel 1: Elevation 79 degrees 0-90
6 Channel 1: Azimuth 048 degrees 0-359
7 Channel 1: SNR (C/No) 42 dBHz 0-99 null when not tracking
8 Channel 2: Satelitte ID 07 1-32 Range: 1-32
9 Channel 2: Elevation 79 degrees 0-90
10 Channel 2: Azimuth 048 degrees 0-359
11 Channel 2: SNR (C/No) 42 dBHz 0-99 null when not tracking
12 Channel 3: Satelitte ID 07 1-32 Range: 1-32
13 Channel 3: Elevation 79 degrees 0-90
14 Channel 3: Azimuth 048 degrees 0-359
15 Channel 3: SNR (C/No) 42 dBHz 0-99 null when not tracking
16 Channel 4: Satelitte ID 07 1-32 Range: 1-32
17 Channel 4: Elevation 79 degrees 0-90
18 Channel 4: Azimuth 048 degrees 0-359
19 Channel 4: SNR (C/No) 42 dBHz 0-99 null when not tracking

Example: $GPGSV,2,1,07,07,79,048,42,02,51,062,43,26,36,256,42,27,27,138,42*71

RMC - Recommended Minimum Specific GNSS Data

ParameterName Example Unit Description
1 UTC Time 161229.487 hhmmss.sss
2 Status A A: Data is valid
V: Data is not valid
3 Latitude 3723.2475 ddmm.mmmm
4 N/S indicator N N=north or S=south
5 Longitude 12158.3416 dddmm.mmmm
6 E/W indicator W E=east or W=west
7 Speed over ground 0.13 knots
8 Course over ground 309.62 degrees
9 Date 120598 ddmmyy
10 Magnetic variation degrees
11 Mode A degrees (NMEA 2.3 or higher)
A: Autonomous

Example: $GPRMC, 161229.487,A,3723.2475,N,12158.3416,W,0.13,309.62,120598,,*10

VTG - Course Over Ground and Ground Speed

ParameterName Example Unit Description
1 Course over ground 309.62 degrees Measured heading
2 Reference T T=True
3 Course degrees Measured heading
4 Reference M M=Magnetic
5 Speed 0.13 knots Measured horizontal speed
6 Units N N=knots
7 Speed 0.2 km/h Measured horizontal speed
8 Units K K=km/h
9 Mode A degrees (NMEA 2.3 or higher)
A: Autonomous

Example: $GPVTG, 309.62, T,,M,0.13,N,0.2,K*6E

MSS - MSK Receiver Signal

ParameterName Example Unit Description
1 Signal strength 55 dB
2 Signal-to-Noise ratio 27 dB
3 Beacon frequency 318.0 kHz Currently tracked frequency
4 Beacon bit rate 100 bps
5 Channel number 1 The channel of the beacon being used if a multi-channel beacon receiver is used. (NMEA 2.3 or higher)

Example: $GPMSS,55,27,318.0,100,1,*57

ZDA - SiRF Timing Message

ParameterName Example Unit Description
1 UTC Time 181813
2 Day 14 days Range: 01-31
3 Month 10 months Range: 01-12
4 Year 2003 years Range: 1980-2079?
5 Local zone hour 00 Offset from UTC
6 Local zone minutes 00 Offset from UTC


RMB - Recommended Minimum Navigation Information

ParameterName Example Unit Description
1 Status A A: Data is valid
V: Data is not valid
2 Crosstrack error 161229.487 nautical miles
3 Direction to steer L: Left
R: Right
4 Origin waypoint id
5 Destination waypoint id
6 Latitude 3723.2475 ddmm.mmmm (For destination waypoint)
7 N/S indicator N N=north or S=south
8 Longitude 12158.3416 dddmm.mmmm (For destination waypoint)
9 E/W indicator W E=east or W=west
10 Range to destination 0.13 nautical miles
11 Bearing to destination 309.62 degrees
12 Destination closing velocity2.2 knots ddmmyy
13 Arrival status degrees A: Entered or perpendicular passed


RMA - Navigation data from present position

ParameterName Example Unit Description
1 Status A A: Data is valid
V: Data is not valid
2 Latitude 3723.2475 ddmm.mmmm
3 N/S indicator N N=north or S=south
4 Longitude 12158.3416 dddmm.mmmm
5 E/W indicator W E=east or W=west
6 not used
7 not used
8 Speed over ground 0.13 knots
9 Course over ground 309.62 degrees
10 Variation degrees
11 Direction of variation E E: East
W: West


SerialMon support