GPS error


#1

Hi all,
in my application I simply activate GPS in internal mode:

adl_gpsSubscribe ( GpsHandler, 1);

ascii Latitude[50];
ascii Longitude[50];
wm_sprintf ( Latitude, GPSData->Position.latitude);
wm_sprintf ( Longitude, GPSData->Position.longitude);
wm_sprintf(Buff,“Latitude: %s ; Longitude: %s\r\n”,Latitude, Longitude);
adl_atSendResponse ( ADL_AT_UNS, Buff );

during first 5 minutes i receive the coordinares normally:

Latitude: 0803.81961 ; Longitude: 03452.69350
Latitude: 0803.81962 ; Longitude: 03452.69349
Latitude: 0803.81963 ; Longitude: 03452.69349
Latitude: 0803.81963 ; Longitude: 03452.69348
Latitude: 0803.81964 ; Longitude: 03452.69348

but after that:

Latitude: ; Longitude:
Latitude: ; Longitude:
Latitude: 0803.81942 ; Longitude: 03452.69422
Latitude: 0803.81940 ; Longitude: 03452.69423
Latitude: ; Longitude:
Latitude: 0803.81944 ; Longitude: 03452.69424
Latitude: ; Longitude:
Latitude: ; Longitude:
Latitude: 0803.81918 ; Longitude: 03452.69412
Latitude: 0803.81935 ; Longitude: 03452.69407

after some time receiving wrong coordinates, i receive them right again, and so on…

the antenna is not moving and the module(Q2501B) is being supplyed by a relyable power source.

any ideas?

Sérgio


#2

Hi Sergio,
there is nothing wrong with that as GPS signal has to follow a pretty long way and the reception is a multi-factor eqn as the signal can be modified by the weather, clouds, multipath and so on.
If the precision is less important than the precision AND the consumption (CPU, current) you could set a reception using GPS + GLONASS at the same time which increase the number of sat. available and you can finally retrieve some precision using some math and in some case the map mapping is a pretty good solution too.
I hope it will gives you a clue to go a step further in your project!
Johann