Fixing Start/Stop pickup

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Srcypher
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Fixing Start/Stop pickup

Post by Srcypher » Mon Jun 02, 2014 1:01 pm

I was at Mid-O, and some sessions didn't pick up the start finish, so I have 2 laps in one;
and some sessions with long times but in a single lap (didn't cancel the lap when exiting)

but recalculating doesn't force a split or correction

What is the correct method to clean up the bad data; the initial searches on the forum didn't flag anything related I could use.

Thanks.
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Harry
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Re: Fixing Start/Stop pickup

Post by Harry » Mon Jun 02, 2014 3:32 pm

Hi,

"After the fact" lap recognition or lap joins are not yet supported. The only way to achieve this is by exporting the lap to hlptrl and editing the file by hand and reimport it. That however is a difficult task (some threads are around, but no complete how-to)... To at least get MidOhio fixed, please export one of the "Multi Laps" and send the hlptrl or kml to Tracks@gps-laptimer.de

Thanks!
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Srcypher
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Re: Fixing Start/Stop pickup

Post by Srcypher » Mon Jun 02, 2014 4:17 pm

Done. i also sent a hlptrl where the track crossed over itself; is that a similar issue?
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Harry
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Re: Fixing Start/Stop pickup

Post by Harry » Mon Jun 02, 2014 4:18 pm

No, that usually means bad GPS reception / accuracy. This by the way is the most frequent reason for missed triggers too... But I will check and let you know.

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Re: Fixing Start/Stop pickup

Post by Harry » Mon Jun 02, 2014 5:08 pm

Well - that's a real GPS problem... From the snapshot you can see that at some point of the track GPS delivered a huge drift (constant translation to one direction). You need to contact the manufacturer of your GPS to clarify if this is a device fault or something that can happen due to some atmospheric disruption etc.
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The stop/go trigger is placed correctly, so no need to adjust that track set from my point of view. With the above translation of position, it is obvious why LapTimer didn't split the laps... :-(

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Srcypher
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Re: Fixing Start/Stop pickup

Post by Srcypher » Mon Jun 02, 2014 9:11 pm

Dualgps 160a is my gps; updated the firmware
gplracerx
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Re: Fixing Start/Stop pickup

Post by gplracerx » Mon Jun 02, 2014 11:00 pm

Wouldn't an atmospheric disruption show up as a drop in the number of satellites and/or a big change in the HDOP. That should be in the hlptrl file.
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Re: Fixing Start/Stop pickup

Post by Harry » Mon Jun 02, 2014 11:08 pm

No, that's the problem. HDOP is a measure for the quality of the satellite geometry. The accuracy derived from it is the worst case assuming the signals received are correct. In case the signal is disturbed, accuracy is probably lower (worse) than reported. Looking into the sample, the blue bubbles (accuracy reported) for the drifted lap show the same size as those for the first lap... Keep in mind, GPS is assumed to report correctly (with accuracy) for 95% of the time only.

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