Data Sheet

LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi District, New Taipei City 221, Taiwan
℡ 886-2-8698-3698
 886-2-8698-3699
www.locosystech.com
Page 8/20
© 2006 LOCOSYS Technology Inc.
 VTG---Course Over Ground and Ground Speed
Table 5.1-10 contains the values for the following example:
$GPVTG,79.65,T,,M,2.69,N,5.0,K,A*38
Table 5.1-10 VTG Data Format
Name Example Units Description
Message ID $GPVTG VTG protocol header
Course over ground 79.65
degrees
Measured heading
Reference T True
Course over ground
degrees
Measured heading
Reference M Magnetic
Speed over ground 2.69
knots
Measured speed
Units N Knots
Speed over ground 5.0
km/hr
Measured speed
Units K Kilometer per hour
Mode A
A=autonomous, D=DGPS, E=DR, N=Data not valid,
R=Coarse Position, S=Simulator
Checksum *38
<CR> <LF> End of message termination
5.2 Proprietary NMEA input message
Please refer to MTK proprietary message.
5.3 Examples to configure the power mode of GPS module
The GPS module supports different power modes that user can configure by issuing
software commands.
5.3.1 Standby mode
User can issue software command to make GPS module go into standby mode that
consumes less than 200uA current. GPS module will be awaked when receiving any byte.
The following flow chart is an example to make GPS module go into standby mode and
then wake up.