gps issue / recorder app

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  • I've used the run and recorder apps simultaneously and went for a run. The run app lost me at 1/3 of the run and found me back arrived at 2/3. It lost the gps signal for a while (I've seen the GPS sign with a red background in the run app. Interestingly, the recorder app has a very different idea about what happened (see file attached Bangle.js Track 3.gpx) and didn't loose my track in 1 long go. Basically, it took the coordinates of the crossing point of the equateur and the prime meridian 0.00000000 -0.00000000 and made me travel back and forth to this point a few times along my run. 1 hour run and almost 137000 kms ! I also have the same track recorded with a Garmin Watch (attached, if needed), it's more spot on, but far from perfect too. This raises multiple questions in my head about different potential issues.


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  • The distance calculation in the run app is basically flawed at the moment for reasons I has described in the run app thread.

    The run app takes position fixes every second, whereas the reorder will do it every X seconds. The later approach is better as the error on the GPS can be up to 20m between fixes on the same spot.

    I'm working on a basic fix for the run app at the moment but long term it needs a kalman filter to smooth out the errors. At the end of the day its the same GPS fix coming into both apps but maybe a different rates.

    There is also the GPS recorder app which I find quite reliable if set to record every 30 seconds, I imagine the recorder app will be just as good at 30 second intervals.

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gps issue / recorder app

Posted by Avatar for Fteacher @Fteacher

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