SkyTraq PX1172R - NMEA GSA - GNSS DOP and Active Satellites; GSA Structure and Field Explanations

18
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GSA–GNSSDOPandActiveSatellites
GNSSreceiveroperatingmode,satellitesusedinthenavigationsolutionreportedbytheGGAorGNSsentenceand
DOPvalues.
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Structure:
$GNGSA,A,x,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,xx,x.x,x.x,x.x,x*hh<CR><LF>
1233333333333345678
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Example: 
$GNGSA,A,3,05,12,13,15,20,21,24,193,,,,,1.2,0.7,1.0,1*08<CR><LF>
$GNGSA,A,3,01,03,04,06,07,13,16,21,26,,,,1.2,0.7,1.0,4*34<CR><LF>
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Field Name Example Description
1 Mode A Mode
‘M’=Manual,forcedtooperatein2Dor3Dmode
‘A’=Automatic,allowedtoautomaticallyswitch2D/3D
2 Mode 3 Fixtype
1=Fixnotavailable
2=2D 
3=3D
3 Satelliteused1~12 05,12,13,15,20,2
1,24,193
01~ 32areforGPS;33 ~ 64areforWAAS(PRNminus87);193
~197areforQZSS;65~88areforGLONASS(GLPRN);01~36
areforGALILEO(GAPRN);01~37areforBDS(BDPRN).GPS,
GLONASS,GALILEOandBDSsatellitesaredifferentiatedbythe
GNSSsystemIDintable3.Maximally12satellitesareincluded
ineachGSAsentence.
4 PDOP 1.2 Positiondilutionofprecision(0.0to99.9)
5 HDOP 0.7 Horizontaldilutionofprecision(0.0to99.9)
6 VDOP 1.0 Verticaldilutionofprecision(0.0to99.9)
7 GNSSSystemID 1 GNSSsystemID
*
1=GPS
2=GLONASS
3=GALILEO
4=BDS
5=IRNSS
8 Checksum 08
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*GNSSSystemIDidentifiestheGNSSsystemIDaccordingtoTable3.
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