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gps

GPS doesn't fix seeing 16 satellites


I'm receiving odd NMEA responses when trying to use GPS:

$GPGSA,A,1,,,,,,,,,,,,,,,*1E

$GPGSV,4,1,16,05,,,,14,,,,11,,,,02,,,*79

$GPGSV,4,2,16,23,,,,28,,,,12,,,,01,,,*71

$GPGSV,4,3,16,32,,,,30,,,,27,,,,26,,,*7A

$GPGSV,4,4,16,21,,,,13,,,,04,,,,03,,,*78

$GPGGA,,,,,,0,,,,,,,,*66

$PQXFI,,,,,,,,,,*56

$GPVTG,,T,,M,,N,,K,N*2C

$GPRMC,,V,,,,,,,,,,N*53

$GPGSA,A,1,,,,,,,,,,,,,,,*1E

$GPGSV,4,1,16,27,,,,03,,,,05,,,,14,,,*7D

$GPGSV,4,2,16,11,,,,02,,,,23,,,,28,,,*71

$GPGSV,4,3,16,12,,,,01,,,,32,,,,30,,,*79

$GPGSV,4,4,16,26,,,,21,,,,13,,,,04,,,*7F

$GPGGA,,,,,,0,,,,,,,,*66

$PQXFI,,,,,,,,,,*56

$GPVTG,,T,,M,,N,,K,N*2C

$GPRMC,,V,,,,,,,,,,N*53

$GPGSA,A,1,,,,,,,,,,,,,,,*1E

and it goes like this on and on, changing only the values in lines beginning with $GPGSV. The device is DW 5620 in Alienware M14x notebook, 3G connection is possible to establish, but it doesn't affect responses shown above. The output is the same in- & outdoors. Could anyone interpret this log, so I would know whether it's a software or hardware issue?


Solution

  • first look at the $GPRMC message: it does not show any data, further it shows status "V" which means invalid fix. Your gps has not yet a valid position.

    So move up from your desk, go out and place the laptop such that it has good view ro open sky. (e.g put it on the roof of a car, or similar and wait, the first time wait for 40 minutes., later it needs only 40s)

    Your receiver does not see 16 satellites. GPGSV tells which sattelites are theoretical in view on sky. and you see that there is no SNR (signal to noise ratio) contained for any sattelite.