Times calculcated from NMEA stream wrong by 1h

Matthias Keller shared this problem 20 days ago
Solved

Hi

I recently switched to Locus Map from the old Locus Map Classic (Pro). I'm using a SimpleRTK2B receiver via bluetooth. However I noticed that the timestamps in the recorded GPX File (or the internal track) are off by one hour.

I'm surrently in GMT+02:00 (Middle-European Summer Time, so DST is active).

In the NMEA Log I see the correct timestamps:

$GNRMC,182417.00,A,4730.73533,N,00835.30759,E,0.021,,150526,,,D,V*19
$GNGGA,182417.00,4730.73533,N,00835.30759,E,2,12,0.50,418.9,M,47.4,M,,0136*4E
I currently don't include GNZDA in the NMEA stream - would this be required?

both show 18:24:17 (=20:24:17 MEST, which is correct) but Locus shows: 'Last Fix 19:24:17' and also uses this timestamp in the recorded tracks.

So I guess there's something off, probably due to DST?

Thanks for confirming and fixing this bug!

Matt

Best Answer
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Thanks Matthias, we've identified the bug - Locus was combining the NMEA UTC time with the day in the device's local timezone, which shifted the saved timestamps by the device's UTC offset (1 hour during summer time / DST). The fix is queued for the next 4.34.x bug-fix release on Google Play and the asamm repo. Thanks for the detailed report and the NMEA log — it pinpointed the cause exactly.

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Replies (4)

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BTW, I just added GNZDA to the NMEA stream, which did not make any difference to this problem. The time is still one hour off.

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Hi Matthias,

please install the latest app version 4.34. This issue should be fixed. It'll be available on Google Play shortly. If you don't want to wait, install it from our repo at https://bit.ly/lmVersions.

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I just got 4.34.0 today via play store. However, the problem still persists. At least the 'last fix' display is still one hour off.

I'd be happy to help debug if you want.

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Posted in the wrong place --- deleted

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Thanks Matthias, we've identified the bug - Locus was combining the NMEA UTC time with the day in the device's local timezone, which shifted the saved timestamps by the device's UTC offset (1 hour during summer time / DST). The fix is queued for the next 4.34.x bug-fix release on Google Play and the asamm repo. Thanks for the detailed report and the NMEA log — it pinpointed the cause exactly.

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Thank you very much!!

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