Reference
Last revision 2026/01/09
NMEA0183 Protocol Introduction
Connect USB GPS receiver to your computer, and place in an open space. Check sensor data on via serial assistant.
The sensor will output the following data:
$GPGGA,061831.000,2236.9152,N,11403.2422,E,2,07,1.1,144.0,M,-2.2,M,4.8,0000*60
$GPGSA,A,3,18,22,25,12,14,21,24,15,,,,,1.93,1.04,1.63*01
$GPGSV,3,1,11,12,40,089,45,14,37,314,46,15,10,078,44,18,77,096,43*72
$GPGSV,3,2,11,21,27,192,31,22,60,330,43,24,24,037,45,25,42,142,41*71
$GPGSV,3,3,11,31,21,230,27,42,51,128,37,50,46,122,39*4D
$GPRMC,061831.000,A,2236.9152,N,11403.2422,E,0.00,,130214,,,D*76
$GPVTG,309.62,T, ,M,0.13,N,0.2,K*6E
GGA
Sample Data: $GPGGA,061831.000,2236.9152,N,11403.2422,E,2,07,1.1,144.0,M,-2.2,M,4.8,0000*60
| Name | Example | Unit | Description |
|---|---|---|---|
| Message ID | $GPGGA | GGA protocol header | |
| UTC time | 061831.000 | hhmmss.sss | |
| Latitude | 2236.9152 | ddmm.mmmm | |
| N/S Indication | N | N=North, S=South | |
| Longitude | 11403.2422 | dddmm.mmmm | |
| E/W Indication | E | W=West, E=East | |
| Position Indication | 2 | 0:unpositioned 1:SPS mode, position valid 2:Differential, SPS mode, position valid, 3:PPS mode, position valid | |
| Satellites Used | 07 | Range: 0 to 12 | |
| HDOP | 1.1 | Horizontal Precision | |
| MSL Altitude | 144.0 | Meters | - |
| Unit | M | Meters | |
| Geoidal | -2.2 | Meters | - |
| Units | M | - | |
| Differential Time | 4.8 | Second | Invalid when DGPS is not used |
| Differential ID | 0000 | ||
| Checksum | * 60 |
GSA
Sample Data: $GPGSA,A,3,18,22,25,12,14,21,24,15,,,,,1.93,1.04,1.63*01
| Name | Sample | Unit | Description |
|---|---|---|---|
| Message ID | $GPGSA | GSA protocol Header | |
| Mode 1 | A | M=Manual(forced to operate in 2D or 3D mode), A=Automatic | |
| Mode 2 | 3 | 1:Position invalid, 2:2D Position, 3:3D Position | |
| Satellite used | 18 | Channel 1 | |
| Satellite used | 22 | Channel 2 | |
| Satellite used | 25 | Channel 3 | |
| Satellite used | 12 | Channel 4 | |
| Satellite used | 14 | Channel 5 | |
| Satellite used | 21 | Channel 6 | |
| Satellite used | 24 | Channel 7 | |
| Satellite used | 15 | Channel 8 | |
| ,,, | ,,, | ,,, | ,,, |
| Satellite used | Channel 12 | ||
| PDOP | 1.93 | Position Precision | |
| HDOP | 1.04 | Horizontal Precision | |
| VDOP | 1.63 | Vertical Precision | |
| Checksum | * 01 |
1.3 GSV
Sample Data:
$GPGSV,3,1,11,12,40,089,45,14,37,314,46,15,10,078,44,18,77,096,43*72
$GPGSV,3,2,11,21,27,192,31,22,60,330,43,24,24,037,45,25,42,142,41*71
$GPGSV,3,3,11,31,21,230,27,42,51,128,37,50,46,122,39*4D
| Name | Sample | Unit | Description |
|---|---|---|---|
| Message ID | $GPGSV | GSV protocol header | |
| Number of messages | 3 | Range 1 to 3 | |
| Message Number | 1 | Range 1 to 3 | |
| Number of satellites | 11 | ||
| Satellite ID | 12 | Range 1 to 32 | |
| Elevation | 40 | Degrees | Max 90° |
| Azimuth | 089 | Degrees | Range 0 to 359° |
| SNR（C/No） | 45 | dBHz | Range 0 to 99, null when not tracking |
| Satellite ID | 14 | Range 1 to 32 | |
| Elevation | 37 | Degrees | Max 90° |
| Azimuth | 314 | Degrees | Range 0 to 359° |
| SNR（C/No） | 46 | dBHz | Range 0 to 99, null when not tracking |
| Satellite ID | 15 | Range 1 to 32 | |
| Elevation | 10 | Degrees | Max 90° |
| Azimuth | 078 | Degrees | Range 0 to 359° |
| SNR（C/No） | 44 | dBHz | Range 0 to 99, null when not tracking |
| Satellite ID | 18 | Range 1 to 32 | |
| Elevation | 77 | Degrees | Max 90° |
| Azimuth | 096 | Degrees | Range 0 to 359° |
| SNR（C/No） | 43 | dBHz | Range 0 to 99, null when not tracking |
| Checksum | * 72 |
RMC
Sample Code: $GPRMC,061831.000,A,2236.9152,N,11403.2422,E,0.00,,130214,,,D*76
| Name | Sample | Unit | Description |
|---|---|---|---|
| Message ID | $GPRMC | RMC Protocol Header | |
| UTC Time | 061831.000 | hhmmss.ss | |
| Status | A | A=Data valid; V=Data invalid | |
| Latitude | 2236.9152 | ddmm.mmmmm | |
| N/S Indication | N | N=North, S=South | |
| Longitude | 11403.2422 | dddmm.mmmm | |
| E/W Indication | E | W=West, E=East | |
| Speed over Ground | 0.00 | Knot（Knots） | |
| Course over Ground | Degrees | ||
| Date | ddmmyy | ||
| Magnetic variation | - | ||
| Checksum | * 76 |
VTG
Sample Data: $GPVTG,309.62,T, ,M,0.13,N,0.2,K*6E
| Name | Sample | Unit | Description |
|---|---|---|---|
| Message ID | $GPVTG | VTG protocol header | |
| Course over Ground | 309.62 | Degrees | |
| Reference | T | True | |
| Course over Ground | 309.62 | Degrees | |
| Reference | M | Magnetic | |
| Speed | 0.13 | Knot（Knots） | |
| Unit | N | Knots | |
| Speed | 0.2 | km/hr | |
| Unit | K | km/hr | |
| Checksum | * 6E |
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