SkyTraq PX1172R - NMEA Output Description; NMEA Sentence Structure and Messages

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NMEAOutputDescription
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TheoutputprotocolsupportsNMEA‐0183standard.TheimplementedmessagesincludeGGA,GLL,GSA,GSV,VTG,
RMC,ZDAandGNSmessages.TheNMEAmessageoutputhasthefollowingsentencestructure:
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$aaccc,c–c*hh<CR><LF>
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ThedetailofthesentencestructureisexplainedinTable1.
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Table1:TheNMEAsentencestructure
character HEX Description
“$” 24 Startofsentence.
Aaccc  Addressfield.“aa”isthetalkeridentifier.“ccc”identifiesthesentencetype.
“,” 2C Fielddelimiter.
C
–
c  Datasentenceblock.
“*” 2A Checksumdelimiter.
Hh  Checksumfield.
<CR><LF> 0D0A Endingofsentence.(carriagereturn,linefeed)
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Table2:OverviewofSkyTraqreceiver’sNMEAmessages 
$GPGGA Time,position,andfixrelateddataofthereceiver.
$GNGLL Position,timeandfixstatus.
$GNGSA UsedtorepresenttheID’sofsatelliteswhichareusedforpositionfix.WhenGPSsatellitesareusedfor
positionfix,$GNGSAsentenceisoutputwithsystemID1.WhenGLONASSsatellitesareusedfor
positionfix,$GNGSAsentenceisoutputwithsystemID2.WhenBDSsatellitesareusedforposition
fix,$GNGSAsentenceisoutputwithsystemID4.
$GPGSV
$GLGSV
$GAGSV
$GBGSV
Satelliteinformationaboutelevation,azimuthandCNR,$GPGSVisusedforGPSsatellites,$GLGSVis
usedforGLONASSsatellites,$GAGSVisusedforGALILEOsatellites,while$GBGSVisusedforBDS
satellites
$GNRMC Time,date,position,courseandspeeddata.
$GNVTG Courseandspeedrelativetotheground.
$GNZDA UTC,day,monthandyearandtimezone.
$GNTHS TrueHeadingandStatus.
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