I connected the GPS module to PC via a cable I took from a mobile phone data cable. So the module is powered via USB and Tx, Rx of the cable is connected to the GPS module.
I can get a GPS fix at cold start within the specifications. However I have some problems with the module. I am listing them here.
- GPS module never sends heading(Course) value. It is always 0. I tried moving around with laptop. But no use.
- The altitude value is always negetive. Which means I am below the sea level.
- I can't enable VTG message. I can enable/disable every other output message using NMEA input sentences, but not VTG.
- The Longitude and the Latitude does not update very often. I observed the same value for Lat/ Lon for 2 mins although I moved around at abbout 3kmph.
Below is GGA, RMC sentences from the module.
Code: Select all
$GPGGA,130712.044,072x.xxxx,N,0800x.xxxx,E,1,04,11.7,-71.5,M,,,,0000*xx
$GPRMC,130712.044,A,072x.xxxx,N,0800x.xxxx,E,0.00,0.00,181210,,*xx
I dumped the firmware using SiRFFlash, the firmware is "2.4.13.03-XTrac2.0.2-C3PROD1.0". So it is Xtrac. GPS chip is SiRFStarII Low Power chip. The module has a built in patch antenna.
So any help is appreciated.