[FOSS-GPS] High accuracy positioning with low cost
GPS devices:a FOSS project
john at coyotebush.net
Fri Oct 17 14:50:09 EDT 2008
> What do you mean by 'interpolation tricks'?
It was pretty simple, but I had to include Doppler shift when I has
adjusting for clock error. I was doing zero baseline measurements - a single
antenna, a signal splitter, and two receivers. The noise was a bit higher
than the AC12 - 8 mm vs 3 mm - but there was no noticeable drift. (I was
using an AC12 reference in both tests.)
If you're not already doing it, I highly recommend starting with zero
baseline measurements. It is an important "debug" step as it ensures you are
grabbing data correctly and your receivers are giving plausible data. I
spent about $60 for a the Wi-Sys Ws2903 signal splitter. It is actually a
Wi-Fi splitter, but it works fine for powered GPS antennas.
BTW, It's a long shot, but I heard the LEA-4S provides raw measurements.
There was a German electronics company which packaged it into a GPS mouse at
a very reasonable price. They don't ship to the US, so I wasn't able to
verify the raw measurements.
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