SkyTraq PX1172R-20 User manual

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PX1172R‐20
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Features
 Decimeter‐levelaccuracyRTKreceiver
 Multi‐Band,Quad‐GNSS
 17mmx22mmsize
 NMEA‐0183andRTCM3.xprotocol
 Easytointegrate
 Operatingtemperature‐40~+85ºC 
 RoHScompliant
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Applications
 HighAccuracyGuidance
 GISdatacollection
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LowCostRTKReceiverfor
Decimeter‐LevelAccuracy
PositioningApplications
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ThePX1172R‐20offersdecimeter‐levelaccuracybasedoncarrier
phase RTK technique and can be used for a wide range of
high‐accuracypositioningapplications.Its17mmx22mmstamp
size makes it ideal for mobile precision positioning application
requiringcompactformfactor.
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ThereceiverreceivesRTCM3.xdatafromalocalbasestation,a
virtualreferencestation(VRS)inaNetworkRTKconfiguration,
oranotherSkyTraqRTKreceiversetupasinbasestationmode
to perform carrier phase RTK processing, achieving decimeter
levelaccuraterelativepositioning.
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The PX1172R‐20 receiver is based on SkyTraq’s
high‐performance Phoenix GNSS chipset, featuring fast signal
acquisition search engine and high‐sensitivity track engine.
Search engine performs 16 million time‐frequency hypothesis
testing per second, offering industry‐leading signal acquisition
performance.
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Thereceiverisoptimizedformassmarketapplicationsrequiring
high‐precision decimeter‐level accuracy, high‐performance, low
power,andlowercost.
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TECHNICALSPECIFICATIONS
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ReceiverType   230channelPhoenixGNSSengine
GPSL1/L2C,BeiDouB1/B2,GalileoE1/E5b,GLONASSL1/L2,QZSSL1/ L 2 C 
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AccuracyPosition1.5mCEPautonomousmode
20cm+1ppmRTKmode
Velocity0.05m/sec*
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Time12ns
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TimetoFirstFix   1secondhot‐startunderopensky(average)
28secondwarm‐startunderopensky(average)
29secondcold‐startunderopensky(average)
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RTKConvergence  <10sec 
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Reacquisition   1s
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MaxUpdateRate  1/2/4/5/8/10Hz
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OperationalLimits  Altitude<80,000mandvelocity<515m/s
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SerialInterface   3.3VLVTTLlevel
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ProtocolNMEA‐0183V4.1
GGA,GLL,GSA,GSV,RMC,VTG
115200baud,8,N,1
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RTCM3.x
115200baud,8,N,1
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DatumDefaultWGS‐84anduserdefinableinstand‐alonemode
DependsonbasereferenceframewheninRTKmode
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InputVoltage   3.3VDC+/‐10%
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CurrentConsumption  100mA
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Dimension17mmLx22mmWx2.9mmH
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Weight:1.7g
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OperatingTemperature ‐40oC~+85oC 
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StorageTemperature  ‐55oC~+100oC
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Humidity5%~95%non‐condensing
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*150%@30m/sfordynamicoperation
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FUNCTIONALDESCRIPTION
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ActiveantennaisrequiredtousewithPX1172R‐20.Thereceivedsignalgoesthroughasignal
splitter,toindividualL1andL2/L5SAWfilterstoremoveout‐bandinterference,thentothePX100
GNSSreceiverchipforRTKsignalprocessing.UsingcorrectiondatafromanRTKbasestation,the
roverPX1172R‐20computesitspositiontocentimeter‐levelaccuracyrelativetothebasestation. 
SUPPORTEDRTCMMESSAGES
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Whenoperatinginrovermode,PX1172R‐20candecodefollowingRTCM3.3messages:
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RTCMMessageType Description
1004 ExtendedL1/L2GPSRTKobservables
1005 StationaryRTKreferencestationantennareferencepoint
1006 StationaryRTKreferencestationARPwithantennaheight
1012 ExtendedL1/L2GLONASSRTKobservables
1033 Receiverandantennadescription
1074 GPSMSM4
1075 GPSMSM5
1076 GPSMSM6
1077 GPSMSM7
1084 GLONASSMSM4
1085 GLONASSMSM5
1086 GLONASSMSM6
1087 GLONASSMSM7
1094 GalileoMSM4
1095 GalileoMSM5
1096 GalileoMSM6
1097 GalileoMSM7
1114
Q
ZSSMSM4
1115 QZSSMSM5
1116 QZSSMSM6

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1117 QZSSMSM7
1124 BeiDouMSM4
1125 BeiDouMSM5
1126 BeiDouMSM6
1127 BeiDouMSM7
1230 GLONASSCode‐PhaseBiases
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PINOUT
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PINOUTDESCRIPTION
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PinNo. Name Description
1
GND Ground
2
RF_IN
RFinput 
3
GND Ground
4,5,6
NC
Noconnection,emptypin
7
VCC_RF
VoltageforexternalLNA
8,9,10,11
NC
Noconnection,emptypin
12
GND
Ground
13
NC
Noconnection,emptypin
14
GND
Ground
15,16,17,18,19
NC
Noconnection,emptypin

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20
RTK_STAT Status signal
0:RTKFix
Blink  :RTKFloat
1:otherwise
21,22,23,24,25
NC
Noconnection,emptypin
26
RXD2
UARTserialdatainput,3.3VLVTTL.
OnesimplexasynchronousserialUARTportisimplemented.ThisUARTinputis
normallyforsendingRTCM‐SC104correctiondataorbasestationSkyTraqraw
measurementdatatothereceiverat115200 baudrate.Inthe idlecondition,
thispinshouldbedrivenHIGH.Ifthedrivingcircuitryispoweredindependently
ofPX1172R‐20,ensurethatthispinisnotdriventoHIGHwhenPX1172R‐20is
put to sleep, or a 10K‐ohm series resistor can be added to minimize leakage
current.
27
TXD2
UARTserialdataoutput,3.3VLVTTL.
Notused.
28,29,30,31
NC
Noconnection,emptypin
32
GND
Ground
33,34
VDD33 Powersupply,3.3VDC
35
NC
Noconnection,emptypin
36
V_BCKP Backupsupply voltage for internalRTC andbackup SRAM,1.3V~ 3.6V. VBAT
must be applied whenever VCC is applied. This pin should be powered
continuously to minimize the startup time. If VCC and V_BCKP are both
removed,thereceiverwillbeinfactorydefaultmodeuponpowerup,alluser
configurationsetislost.Forapplicationsthedoesnotcarecoldstartingevery
time,thispincanbeconnecttoVCC.
37
GND
Ground
38,39,40
NC
Noconnection,emptypin
41
GND
Ground
42
TXD UARTserialdataoutput,3.3VLVTTL.
One full‐duplex asynchronous serial UART port is implemented. This UART
output is normally used for sending position, time and velocityinformation
fromthereceiverinNMEA‐0183format.Whenidle,thispinoutputHIGH.
43
RXD UARTserialdatainput,3.3VLVTTL.
Onefull‐duplexasynchronousserialUARTportisimplemented.ThisUARTinput
is normally for sending commands or information to the receiver in SkyTraq
binary protocol. In the idle condition, this pin should be driven HIGH. If the
drivingcircuitryispoweredindependentlyofPX1172R‐20,ensurethatthispin
is not driven to HIGH when PX1172R‐20 is put to sleep, or a 10K‐ohm series
resistorcanbeaddedtominimizeleakagecurrent.
RTCM‐SC104correctiondatacanalsobesenttothisUARTinput.
44
SDA
Notused,leaveunconnected
45
SCL Notused,leaveunconnected
46,47
NC
Noconnection,emptypin
48
GND
Ground
49
RSTN Externalactive‐lowresetinputto thebaseband.
Onlyneededwhenpowersupplyrisetimeisverysloworsoftwarecontrolled
resetisdesired.
50
BOOT_SEL
Noconnectionfornormaluse.Pull‐lowforloadingfirmwareintoemptyor
corruptedFlashmemoryfromROMmode.
51
TRIG
Externalinterrupttriggerinput
52
NC
Noconnection,emptypin

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53
1PPS
One‐pulse‐per‐second (1PPS) time mark output, 3.3V LV‐TTL. The rising edge
synchronizedtoUTCsecondwhengetting3Dpositionfix.Thepulsedurationis
about100msecatrateof1Hz.
54
NC
Noconnection,emptypin
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TheRTCMcorrectiondatacanbeinputfromeitherpin‐43RXDorpin‐26RXD2,butnotboth.
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MECHANICALDIMENSION
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Symbol Dimension(mm)
A 17.00
B 22.00
C 3.85
D 1.05
E 1.90
F 1.10
G 0.80
H 1.50
K 3.65
L 3.25
M 2.10
N 1.10
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ELECTRICALSPECIFICATIONS
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ABSOLUTEMAXIMUMRATINGS
Parameter Minimum Maximum Condition
SupplyVoltage(VCC) ‐0.5 3.6 Volt
BackupBatteryVoltage(V_BCKP) ‐0.5 3.6 Volt
InputPinVoltage ‐0.5 VCC+0.5 Volt
InputPoweratRF_IN  +5 dBm
StorageTemperature ‐55 +100 degC
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OPERATINGCONDITIONS
Parameter Min Typ Max Unit
SupplyVoltage(VDD33) 3 3.3 3.6 Volt
AcquisitionCurrent(excludeactiveantennacurrent)  100  mA
TrackingCurrent(excludeactiveantennacurrent)  100  mA
BackupVoltage(V_BCKP) 1.3  3.6 Volt
BackupCurrent(VDD33voltageapplied)  54  uA
BackupCurrent(VDD33voltageoff)  13  uA
OutputLowVoltage   0.4 Volt
OutputHIGHVoltage 2.4   Volt
InputLOWVoltage   0.8 Volt
InputHIGHVoltage 2   Volt
InputLOWCurrent ‐10  10 uA
InputHIGHCurrent ‐10  10 uA
RFInputImpedance(RF_IN)  50  Ohm
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APPLICATIONCIRCUIT
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ForPrecisePositioning,RoverModeConfiguration1
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ForPrecisePositioning,RoverModeConfiguration2 
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RECOMMANDEDREFLOWPROFILE
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Thereflowprofileshownaboveshouldnotbeexceeded,sinceexcessivetemperaturesortransporttimesduring
reflowcandamagethemodule.Coolingtemperaturefallrate:max3°C/sec


12
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ANTENNACONSIDERATIONS

The PX1172R‐20 is designed to be used with GPS L1/L2C, GLONASS L1/L2, Beidou B1I/B2I, Galileo E1/E5b
multi‐frequency active antenna. Antenna with gain up to 40dB and noise figure less than 2dB can be used. It is
importanttoselectahigh‐performanceantennatoachieveoptimalRTKperformance. 


POWERSUPPLYREQUIREMENT

PX1172R‐20 requires a stable power supply, avoid ripple on VCC pin (<50mVpp). Power supplynoise can affect the
receiver’ssensitivity.BypasscapacitorsshouldbeplacedclosetothemoduleVCCpin,withvaluesadjusteddepending
ontheamountandtypeofnoisepresentonthesupplyline.



BACKUPSUPPLY 

The purpose of backup supply voltage pin (V_BCKP) is to keep the SRAM memory and the RTC powered when the
moduleispowereddown.Thisenablesthemoduletohaveafastertime‐to‐first‐fixwhenthemoduleispoweredon
again.Thebackupcurrentdrainislessthan55μA.Innormalpoweredonstate,theinternalprocessoraccesstheSRAM
andcurrentdrainishigherinactivemode



1PPSOUTPUT 

A1pulsepersecondsignal(100msecHIGHduration)isgeneratedon1PPSpinwhenthereceiverhas3Dpositionfix
using4ormoresatellites.TherisingedgeofthepulseisalignedwithUTCsecond,withaccuracyofabout10nsec.It
outputsconstantLOWwhennopositionfixisavailableinitially. 



LAYOUTGUIDELINES 

SeparateRFanddigitalcircuitsintodifferentPCBregions. 

Itisnecessarytomaintain50‐ohmimpedancethroughouttheentireRFsignalpath.TrykeepingtheRFsignalpathas
shortaspossible. 

DonotroutetheRFsignallinenearnoisysourcessuchasdigitalsignals,oscillators,switchingpowersupplies,orother
RF transmitting circuit. Do not route the RF signal under or over any other components (includingPX1172R‐20), or
othersignaltraces.DonotroutetheRFsignalpathonaninnerlayerofamulti‐layerPCBtominimizesignalloss.

AvoidsharpbendsforRFsignalpath.Maketwo45‐degbendsoracircularbendinsteadofasingle90‐degreebendif
needed.

Avoid vias with RF signal path whenever possible. Every via addsinductiveimpedance.Viasareacceptablefor
connectingtheRFgroundsbetweendifferentlayers.Eachofthemodule’sgroundpinsshouldhaveshorttracetying
immediatelytothegroundplanebelowthroughavia.

ThebypasscapacitorsshouldbelowESRceramictypesandlocateddirectlyadjacenttothepintheyarefor.






13
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HANDLINGGUIDELINE

ThePX1172R‐20modulesareratedMSL4,mustbeusedforSMTreflowmountingwithin72hoursaftertakenoutfrom
the vacuumed ESD‐protective moisture barrier bag in factory condition < 30degC / 60% RH. If this floor life time is
exceeded,orifthereceivedESD‐protectivemoisturebarrierbagisnotinvacuumedstate,thenthedeviceneedtobe
pre‐bakedbeforeSMTreflowprocess.Bakingistobedoneat85degCfor8to12hours.Oncebaked,floorlifecounting
beginsfrom0,andhas72hoursoffloorlifeatfactorycondition<30degC/60%RH.

PX1172R‐20moduleisESDsensitivedeviceandshouldbehandledwithcare.



RTKUsageGuideline

BelowconditionsarerequiredforgettingRTKfixsolution.Iftheconditionsarenotmet,PX1172R‐20willonlyhave
floatorDGPS/3DsolutionandbehavelikeanormalGNSSreceiver.

*Openskyenvironmentwithoutinterference
*Signalover37dB/Hz 
*14ormoresatellitesabove15degreeelevationanglewithgoodsatellitegeometryorlowDOPvalue;generallymore
satelliteswillhavefasterRTKfix

14
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NMEAOutputDescription

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:

$aaccc,c–c*hh<CR><LF>

ThedetailofthesentencestructureisexplainedinTable1.

Table1:TheNMEAsentencestructure
character HEX Description
“$” 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)


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,$GNGSAsentenceisoutputwithsystemID2.WhenGalileosatellitesareusedforposition
fix,$GNGSAsentenceisoutputwithsystemID3.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.



















15
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TheformatsofthesupportedNMEAmessagesaredescribedasfollows:
GGA–GlobalPositioningSystemFixData
Time,positionandfixrelateddataforaGPSreceiver. 

Structure:
$GPGGA,hhmmss.sss,ddmm.mmmmmmm,a,dddmm.mmmmmmm,a,x,xx,x.x,x.x,M,x.x,M,x.x,xxxx*hh<CR><LF>
123456789101112

Example: 
$GPGGA,033010.000,2447.0895508,N,12100.5234656,E,4,12,0.7,94.615,M,19.600,M,,0000*66<CR><LF>

Field Name Example Description
1 UTCTime 033010.000 UTCofpositioninhhmmss.sssformat,(000000.000~235959.999)
2 Latitude 2447.0895508 Latitudeinddmm.mmmmmmmformat
Leadingzerostransmitted
3 N/SIndicator N Latitudehemisphereindicator,‘N’=North,‘S’=South
4 Longitude 12100.5234656 Longitudeindddmm.mmmmmmmformat
Leadingzerostransmitted
5 E/WIndicator E Longitudehemisphereindicator,‘E’ =East,‘W’=West
6 GPSquality
indicator

4 GPSqualityindicator
0:positionfixunavailable
1:validpositionfix,SPSmode 
2:validpositionfix,differentialGPSmode
3:GPSPPSMode,fixvalid
4:RealTimeKinematic.SystemusedinRTKmodewithfixedintegers
5:FloatRTK.SatellitesystemusedinRTKmode.,floatingintegers
6:Estimated(deadreckoning)Mode
7:ManualInputMode
8:SimulatorMode
7 SatellitesUsed 12 Numberofsatellitesinuse,(00~12)
8 HDOP 0.7 Horizontaldilutionofprecision,(0.0~99.9)
9 Altitude 94.615 meansealevel(geoid),(‐9999.9~17999.9)
10 GeoidalSeparation 19.600 Geoidalseparationinmeters
11 AgepfDifferential
GPSdata
AgeofDifferentialGPSdata
NULLwhenDGPSnotused
12 DGPSStationID 0000 DifferentialreferencestationID,0000~1023
13 Checksum 66

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16
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GLL–Latitude/Longitude
Latitudeandlongitudeofcurrentposition,time,andstatus.

Structure:
$GNGLL,ddmm.mmmmmmm,a,dddmm.mmmmmmm,a,hhmmss.sss,A,a*hh<CR><LF>
12345678

Example: 
$GNGLL,2447.0895508,N,12100.5234656,E,033010.000,A,D*48<CR><LF>

Field Name Example Description
1 Latitude 2447.0895508 Latitudeinddmm.mmmmmmmformat
Leadingzerostransmitted
2 N/SIndicator N Latitudehemisphereindicator
‘N’=North
‘S’=South
3 Longitude 12100.5234656 Longitudeindddmm.mmmmmmmformat
Leadingzerostransmitted
4 E/WIndicator E Longitudehemisphereindicator
‘E’=East
‘W’=West
5 UTCTime 033010.000 UTCtimeinhhmmss.sssformat(000000.000~235959.999)
6 Status A Status,‘A’=Datavalid,‘V’=Datanotvalid
7 ModeIndicator D Modeindicator
‘A’=Autonomousmode
‘D’=Differentialmode
‘E’=Estimated(deadreckoning)mode
‘M’=Manualinputmode
‘S’=Simulatormode
‘N’=Datanotvalid
8 Checksum 48








17
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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.


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

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>

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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*GNSSSignalIDidentifiestheGNSSsignalnameaccordingtoTable3.
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Table3:GNSSIdentificationTableforGSA,GSV
System SystemID(Talker) SignalID SignalName
GPS 1(GP) 0
1
2
3
4
5
6
7
8
Allsignals
L1C/A
L1 P(Y)
L1C
L2 P(Y)
L2C‐M
L2C‐L
L5‐I
L5‐Q
GLONASS 2(GL) 0
1
2
3
4
All signals
G1 C/A
G1P
G2 C/A
GLONASS (M) G2P
GALILEO 3(GA) 0
1
2
3
4
5
6
7
All signals
E5a
E5b
E5 a+b
E6‐A
E6‐BC
L1‐A
L1‐BC
BDS 4(BD) 0
1
5
B
8
3
All signals
B1
B2A
B2
B3
B1C
IRNSS 5(GI) 0
4
All signals
L5
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GSV–GNSSSatellitesinView
Numberofsatellites(SV)inview,satelliteIDnumbers,elevation,azimuth,andSNRvalue.Foursatellitesmaximumper
transmission. 

Structure:
$GPGSV,x,x,xx,xx,xx,xxx,xx,…,xx,xx,xxx,xx,x*hh<CR><LF>
1234567456789

Example: 
$GPGSV,3,1,10,24,83,125,48,193,66,057,44,21,53,277,45,15,43,034,47,1*58<CR><LF>
$GPGSV,3,2,10,20,40,325,43,05,16,113,40,13,15,050,39,12,14,146,42,1*6E<CR><LF>
$GPGSV,3,3,10,10,13,314,,32,06,261,,1*62<CR><LF>
$GPGSV,2,1,05,24,83,125,49,193,66,057,44,15,43,034,45,05,16,113,36,6*5B<CR><LF>
$GPGSV,2,2,05,12,14,146,37,6*57<CR><LF>
$GBGSV,3,1,09,13,65,247,45,06,60,334,43,03,59,204,41,26,58,153,47,1*7E<CR><LF>
$GBGSV,3,2,09,16,57,325,45,01,53,142,42,21,52,046,47,04,38,118,,1*7A<CR><LF>
$GBGSV,3,3,09,07,20,169,37,1*40<CR><LF>
$GBGSV,2,1,07,13,65,247,47,06,60,334,47,03,59,204,47,16,57,325,47,3*7C<CR><LF>
$GBGSV,2,2,07,01,53,142,49,04,38,118,45,07,20,169,43,3*44<CR><LF>
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Field Name Example Description
1 Numberofmessage 3 TotalnumberofGSV messagestobetransmitted(1‐5)
2 Sequencenumber 1 SequencenumberofcurrentGSVmessage
3 Satellitesinview 10 Totalnumberofsatellitesinview (00~20)
4 SatelliteID 24 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4satellitesareincludedin
eachGSVsentence.
5 Elevation 83 Satelliteelevationindegrees,(00~90)
6 Azimuth 125 Satelliteazimuthangleindegrees,(000~359)
7 SNR 48 C/NoindB(00~99)
Nullwhennottracking
8 SignalID 1 SignalID*
9 Checksum 58
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RMC–RecommendedMinimumSpecificGNSSData
Time,date,position,courseandspeeddataprovidedbyaGNSSnavigationreceiver.

Structure:
$GPRMC,hhmmss.sss,A,dddmm.mmmmmmm,a,dddmm.mmmmmmm,a,x.x,x.x,ddmmyy,,,a,a*hh<CR><LF>
123456789101112
Example: 
$GNRMC,033010.000,A,2447.0895508,N,12100.5234656,E,000.0,000.0,111219,,,R,V*18<CR><LF>

Field Name Example Description
1 UTCtime 033010.000 UTCtimeinhhmmss.sssformat(000000.00~235959.999)
2 Status A Status
‘V’=Navigationreceiverwarning
‘A’=DataValid
3 Latitude 2447.0895508 Latitudeindddmm.mmmmmmmformat
Leadingzerostransmitted
4 N/Sindicator N Latitudehemisphereindicator
‘N’=North
‘S’=South
5 Longitude 12100.5234656 Longitudeindddmm.mmmmmmmformat
Leadingzerostransmitted
6 E/WIndicator E Longitudehemisphereindicator
‘E’=East
‘W’=West
7 Speedoverground 000.0 Speedovergroundinknots(000.0~999.9)
8 Courseoverground 000.0 Courseovergroundindegrees(000.0~359.9)
9 UTCDate 111219 UTCdateofpositionfix,ddmmyyformat
10 Modeindicator R Modeindicator
‘A’=Autonomousmode
‘D’=Differentialmode
‘E’=Estimated(deadreckoning)mode
‘F’=FloatRTK.SatellitesystemusedinRTKmode,floating
integers
‘M’=ManualInputMode
‘N’=Datanotvalid
‘P’=Precise
‘R’=RealTimeKinematic.SystemusedinRTKmodewithfixed
integers
‘S’=SimulatorMode
11 Navigationstatus V NavigationstatusindicatoraccordingtoIEC61108requirement
on‘Navigational(orFailure)warningsandstatusindicators’.
‘S’=Safe
‘C’=Caution
‘U’=Unsafe
‘V’=Navigationstatusnotvalid,equipmentisnotproviding
navigationstatusindicator.
12 checksum 18
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