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Wrong GPS timestamp in FIT file (delay)

Luko79
over 4 years ago

Hi,

 can You tell me why has it ~8sec delay? (i noticed it 2 months ago just i was lazy to reporting it but it is annoying now...)  i compared my 4 devices, depending on GPS timestamps, here is the result : (we rode next to each other btw...) i dont use BT connection , the Edge 830 is using GPS+GALILEO setting only 

#1: Strava flyby, showing ~8s delay , BUT ON THE 830 THE "time of day" DATAFIELD IS SHOWING EXACTLY THE SAME TIME as on my other /Garmin/ devices, then WHY did it write different GPS timestamp into the FIT file??? It looks like (as i opened both FIT files with editor) the EDGE 830 is adding 8sec to the timestamps everywhere , i started my both Garmins in same time (as i wrote, the time of day datafield is showing exaclty the same time on all of the 4 units, it is changing the minutes in same time) . So why does it add this 8secs from the program code unnecessary?

#2: QS comparison with 4 devices: it is clearly showing that only the 830 is delaying with 8secs apprx

BR,

Andras

  • 0 over 4 years ago

    Andras, can you check also if the elevation profile is affected ? in Strava or GC

    ?

  • 0 over 4 years ago in reply to krazyeone

    Of course, that has ~8sec offset also, every datapoints (so lat/lon, altitude, power, hr etc) is shifted with this , if the 830's timestamp is early with this 8s amount then in the comparison the lat/lon position and the altitude is behind the real position with 8s as my pictures are showing. I will post a altitude comparison chart soon.

    here it is a part from my 830 and F3 altitude comparison  , i think the offset is cleary visible for everybody  

     

  • 0 over 4 years ago in reply to krazyeone

    I put the 2 comparisons into one screen, easier to spot the delay

  • 0 over 4 years ago in reply to krazyeone

    Update: today i tried it with GPS+GLONASS setting on the 830, now the timestamps are correct, no delay, tomorrow i will try it with GPS+GALILEO again ( i was using on it in the past almost everytime), if the offset delay will happen again, then something is wrong with this +GALILEO setting.

  • 0 over 3 years ago in reply to Luko79

    hello, I have similar problem with yours
    I am using garmin edge 830 - purchased it recently
    I noticed in Strava Flyby that my position is like 10-15 seconds delayed from the other riders, which should not be as we were riding together,
    Have you managed to solve this issue ? If yes, how ?
    thanks

  • 0 over 3 years ago in reply to masbul

     as i experienced, i have to completely turn off and on the Edge unit, then the timestamps are ok in the file. if i only put it into sleep mode (short press power button) then the timestamp in the file is wrong (even the displayed time on "Time of Day" datafield is accurate, i checked it many times), i think there is a bug in the firmware and if the unit is not completely turned off then there is mismatch between the recorded time and displayed time.

    So i always turn off and on my unit (sometimes 2 times) before every outdoor ride. 

  • 0 over 3 years ago in reply to Luko79

    thanks for the reply..
    Interesting. and that's a bit weird..
    anyway, I will try it at my next group ride and see the result on Strava Flyby
    cheers

  • 0 over 3 years ago in reply to masbul

    Well maybe not that weird. I am pretty sure that the unit receives the time from the satellites when it is turned on. Then the internal timer takes over. And like most units, the timer is often not that precise. That is why a turn off/on will update to the correct time. I guess... ;) 

  • 0 over 3 years ago in reply to jjespdk

    the internal timer gets accurate with the sleep on/off too (as i wrote the "time of the day" field is accurate with the gps time by second) but the timestamp in the FIT file is delayed (and this cause the flyby delay on strava)

  • 0 over 3 years ago in reply to Luko79

    Ok, I stand corrected then :)