DR + GPS
STARTER KIT REFERENCE MANUAL
Lassen DR + GPS Reference Manual 43

VTG - Track Made Good and Ground Speed

The VTG message conveys the actual track made good (COG) and the speed
relative to the ground (SOG).
$GPVTG,x.x,T,x.x,M,x.x,N,x.x,K,i*hh<CR><LF>

Table 9: VTG Message

Field # Description
1 Track made good in degrees true.
2 Track made good in degrees magnetic.
3, 4 Speed over the ground (SOG) in knots.
5, 6 Speed over the ground (SOG) in kilometer per hour.
7 Mode Indicator: A=Autonomous Mode, D=Differential Mode,
E=Estimated (dead reckoning) Mode, M=Manual Input Mode,
S=Simulated Mode, N-Data Not Valid
hh Checksum
EXCEPTION BEHAVIOR
When no position fix is available, some of the data fields in the NMEA messages
will be blank. A blank field has no characters between the commas.