GPS time in AC2 logs

Hi I see a time field in the GPS data of my AC2 log, common sense tells me this is some kind of GPS time or Unix TS but does not seem to compute, is there a way to convert the value in my log to a date?

the value is: 68098250

which converts to UTC    Mar 04, 1982    04:10:49    UTC

which is NOT the date that I flew (oct 19, 2011 mountain time)



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  • I was curious about this myself, so I started to look into the code.

    The GPS time in the log is actually the UTC time of the day converted to milliseconds. The binary protocol from the MTK GPS used here is a custom protocol for DIY Drones, you can find it here, scroll down to the bottom of the page. The conversion is done in AP_GPS_MTK16.cpp, which is in the AP_GPS library.

    If my math is right then the time you flew was at 18:54:58 UTC, which should be 12:54:58 US/Mountain, you flew during lunch time.

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