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We are testing out Android application on real world devices and notice some of them report very unaccurate data (even under clear sky and over 10 sats seen and 5 sats used), and even reporting speed over 10km/h when the device is not actually moving, and at the same time some devices retun 0 when location.getAccuracy is called.

We have managed to parse NMEA data, and NMEA reports "1" which means that the data is reliable.

This sometimes happens to different makes and models based on different hardware and different Android version. The most unreliable are S-E Xperia x8 (sometimes we get fixes at 20-30kms from real location) and Alcatel 918D (it is always moving over 5km/h and accuracy==0)

Turning A-GPS helper off and on as well as clearing/re-requesting A-GPS updates does not help.

Is there any way to filter such unaccurate fixes "by hand" (with some other NMEA stanzas, etc.) becuase some other software report the location much better on the same devices?

P.S. On most devices we get fine results, as expected.

P.P.S. The most accurate is my own Garmin-Asus. Hope they join again someday.

saabeilin
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  • I think this is a problem with the devices themselves rather than your app. – Joe Simpson Jun 29 '12 at 20:35
  • But some apps, anyway, manage to display the correct location at the same time! That means that they filter the geofixes in some way. But they are proprietary and no legal way to explore what they do. – saabeilin Jun 29 '12 at 20:45
  • I have experienced a smiliar problem we have over 30 devices in truks and sometimes (usualy the same location) the truk jumps over 300 km we figured there is some sort of gps scrambler or signal interference in that location try the device on a diferent location may be it helps if not its probably a faulty device – sherif Jun 29 '12 at 20:49
  • can you show us some gps releated code ? – sherif Jun 29 '12 at 20:51
  • This also happens in very different places - with different landscape, altitude, etc. – saabeilin Jun 29 '12 at 20:51
  • The GPS-related code is typical, nothing special except NMEA receiver/parser. – saabeilin Jun 29 '12 at 21:38
  • Are you requesting absolute location information via permissions? – Joe Simpson Jun 30 '12 at 18:46

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