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ADAFruit GPS

rattustrattus

Hi,

 

I am trying to use an ADAFruit Flora GPS module as a time source, and am seeing something interesting, it appears its getting time out of order, below are grabbed check sum checked output lines in order :-

 

[$GPRMC,214303.000,A,5113.9147,N,00219.7506,W,0.31,234.61,250116,,,A*79][79]

Mon Jan 25 21:43:03 GMT 2016

[$GPRMC,214304.000,A,5113.9147,N,00219.7505,W,0.24,234.61,250116,,,A*79][79]

Mon Jan 25 21:43:04 GMT 2016

[$GPRMC,214300.000,A,5113.9148,N,00219.7510,W,0.45,234.61,250116,,,A*71][71]

Mon Jan 25 21:43:00 GMT 2016

[$GPRMC,214300.000,A,5113.9148,N,00219.7510,W,0.45,234.61,250116,,,A*71][71]

Mon Jan 25 21:43:00 GMT 2016

[$GPRMC,214305.000,A,5113.9147,N,00219.7504,W,0.30,234.61,250116,,,A*7C][7c]

Mon Jan 25 21:43:05 GMT 2016

[$GPRMC,214303.000,A,5113.9147,N,00219.7506,W,0.31,234.61,250116,,,A*79][79]

Mon Jan 25 21:43:03 GMT 2016

[$GPRMC,214304.000,A,5113.9147,N,00219.7505,W,0.24,234.61,250116,,,A*79][79]

Mon Jan 25 21:43:04 GMT 2016

[$GPRMC,214306.000,A,5113.9147,N,00219.7502,W,0.17,234.61,250116,,,A*7C][7c]

Mon Jan 25 21:43:06 GMT 2016

 

Does anyone have any suggestions why I might be seeing this?

 

thanks in advance,

 

Kevin.

Parents

  •     I believe this warning may apply to you:

    GPS modules will always send data EVEN IF THEY DO NOT HAVE A FIX! In order to get 'valid' (not-blank) data you must have the GPS module directly outside, with the square ceramic antenna pointing up with a clear sky view. In ideal conditions, the module can get a fix in under 45 seconds. however depending on your location, satellite configuration, solar flares, tall buildings nearby, RF noise, etc it may take up to half an hour (or more) to get a fix! This does not mean your GPS module is broken, the GPS module will always work as fast as it can to get a fix.

         Check and let me know.

    Clem

Reply

  •     I believe this warning may apply to you:

    GPS modules will always send data EVEN IF THEY DO NOT HAVE A FIX! In order to get 'valid' (not-blank) data you must have the GPS module directly outside, with the square ceramic antenna pointing up with a clear sky view. In ideal conditions, the module can get a fix in under 45 seconds. however depending on your location, satellite configuration, solar flares, tall buildings nearby, RF noise, etc it may take up to half an hour (or more) to get a fix! This does not mean your GPS module is broken, the GPS module will always work as fast as it can to get a fix.

         Check and let me know.

    Clem

Children
  • in reply to clem57

    Thanks Clem,

     

    I did actually check I had a fix, also attached an external GPS antennae to it as well. I did have another GPS module I had been using for just location and swapped the two and the weird time issue went away, so I am now assuming its something wrong with the module itself, but since it works for location I have just swapped the two devices and now have ntpd happily talking to the module.

     

    Kev.

  • in reply to clem57

    As a few of us have been saying n other posts, the current range of GPS units can work very well even in a basement, yes it takes longer to get stabilized but it does get there, mine will lock onto about 13 satelites even from the basment

     

    none of this explains the out of order messages though

     

    On my unit there is a one second pulse LED once a lock is achieved, up untill lock this LED does not flash so it is quite easy to see.