GPS field trips

Marcus Bauer marcus.bauer at gmail.com
Wed Apr 16 10:34:52 CEST 2008


On Wed, 2008-04-16 at 03:45 -0300, Werner Almesberger wrote:

> I also have a few GTA01 and HXD8 laying around, but they're not in a
> state fit for quick GPS testing.

My GTA01 at roof-top conditions generally gets a fix in <60s, time in
<10s.

However, the altitude calculation is broken, it seems gllin has no idea
of the separation of the geoid and WGS84 ellipsoid.

Example:
$GPGGA,115900.000,4341.5434,N,00717.4516,E,1,07,1.1,8.5,M,48.4,M,,0000*51
                                                          ^^^^
                                          the 48.4m are this separation.

They are not calculated from satellite data. The gllin seems to
calculate some garbage value there <1m. Thus altitude is ~48.4m too high
where I live.

Marcus






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