Linx Technologies RXM-GPS-R4 - Manual (Page 9)

– – – – 12 13
NMEA Output Messages
The following sections outline the data structures of the various NMEA
messages that are supported by the module. By default, the commands
are at 9,600bps, 8 data bits, 1 start bit, 2 stop bits, and no parity.
GGA – Global Positioning System Fixed Data
Figure 8 contains the values for the following example:
$GPGGA,053740.000,2503.6319,N,12136.0099,E,1,08,1.1,63.8,M,15.2,M,,0000*64
Global Positioning System Fixed Data Example
Name Example Units Description
Message ID $GPGGA GGA protocol header
UTC Time 053740.000 hhmmss.sss
Latitude 2503.6319 ddmm.mmmm
N/S Indicator N N=north or S=south
Longitude 12136.0099 dddmm.mmmm
E/W Indicator E E=east or W=west
Position Fix Indicator 1 See Figure 9
Satellites Used 08 Range 0 to 12.
HDOP 1.1 Horizontal Dilution of Precision
MSL Altitude 63.8 meters
Units M meters
Geoid Separation 15.2 meters
Units M meters
Age of Diff. Corr. second Null fields when DGPS is not used
Diff. Ref. Station 0000
Checksum *64
<CR> <LF> End of message termination
Figure 8: Global Positioning System Fixed Data Example
Position Indicator Values
Value Description
0 Fix not available or invalid
1 GPS SPS Mode, fix valid
2 Differential GPS, SPS Mode, fix valid
3–5 Not supported
6 Dead Reckoning Mode, fix valid
Figure 9: Position Indicator Values
GLL – Geographic Position – Latitude / Longitude
Figure 10 contains the values for the following example:
$GPGLL,2503.6319,N,12136.0099,E,053740.000,A,A*52
GSA – GPS DOP and Active Satellites
Figure 11 contains the values for the following example:
$GPGSA,A,3,24,07,17,11,28,08,20,04,,,,,2.0,1.1,1.7*35
GPS DOP and Active Satellites Example
Name Example Units Description
Message ID $GPGSA GSA protocol header
Mode 1 A See Figure 12
Mode 2 3 1=No fix, 2=2D, 3=3D
ID of satellite used 24 Sv on Channel 1
ID of satellite used 07 Sv on Channel 2
... ...
ID of satellite used Sv on Channel 12
PDOP 2.0 Position Dilution of Precision
HDOP 1.1 Horizontal Dilution of Precision
VDOP 1.7 Vertical Dilution of Precision
Checksum *35
<CR> <LF> End of message termination
Figure 10: Geographic Position – Latitude / Longitude Example
Geographic Position – Latitude / Longitude Example
Name Example Units Description
Message ID $GPGLL GLL protocol header
Latitude 2503.6319 ddmm.mmmm
N/S Indicator N N=north or S=south
Longitude 12136.0099 dddmm.mmmm
E/W Indicator E E=east or W=west
UTC Time 053740.000 hhmmss.sss
Status A A=data valid or V=data not valid
Mode A
A=autonomous, D=DGPS, N=Data
not valid
Checksum *52
<CR> <LF> End of message termination
Figure 11: GPS DOP and Active Satellites Example