Reference Manual Instruction Manual

662
Query Command Library
Comments In the GSM: information line, the GSM version will appear
only after the modem has been turned on. The stack IP
version will appear only after a GPRS connection has been
established.
See also $PASHQ,RID
VTG: Course Over Ground and Ground Speed
Function This command is used to output a VTG message. The
message is not output until a valid position is computed.
Command Format Syntax
$PASHQ,VTG[*cc]
Response Format Syntax
$GPVTG,f1,T,f2,M,f3,N,f4,K,c5*cc
Parameters
Comments The magnetic table used is the WMM-2005 (published Dec
2004), which is the standard model of the US Department of
Defense (WMM for “World Magnetic Model”).
Example $PASHQ,VTG
$GPVTG,128.00,T,129.92,M,0.17,N,0.31,K,A*2D
Parameter Description Range
f1,T
COG (with respect to True North)
T for “True” North: COG orientation
000.00-359.99
f2,M
COG (with respect to Magnetic North)
M for “Magnetic” North: COG orientation
000.00-359.99
f3,N
SOG (Speed Over Ground)
N for “knots”: SOG unit
000.00-999.99
f4,K
SOG (Speed Over Ground)
K for “km/hr”: SOG unit
000.00-999-99
c5
Mode indicator:
• A: Autonomous mode
• D: Differential mode
• N: Data not valid
A, D, N
*cc Checksum *00-*FF