GPS Errors (GPS-0 / GPS-1 / GPS failsafe)

Posted by Sune Nielsen on August 31, 2015 at 6:40am

I have some sketchy pixhawk behavior that I hope someone can help me localize. I have noticed it 3 times now, and it is rather nerving. 2 times it has been in Auto and 1 time in Loiter. The hex starts fine and flies steadily and controlled, but then suddenly it picks up speed, banks drastically (arround 35 degrees) and goes completely of track.

Looking through the logs (attached) I can see there are GPS-0, GPS-1 and GPS failsafe errors. Can someone explain what causes these errors, considering that they only appear occasionally?
Is it pixhawk settings / calibration?
Is it faulty hardware, pixhawk, gps/compass-module or perhaps wiring?
Regardless of what the issue is I am also very puzzled by the fact that it reacts with picking up speed and banking as drastically as it does. The flightplans I have used has specified speed to 2 or 3 m/s. So what is allowing it to exceed this speed?
I have attached a log file. Hope someone can provide some input that can help me resolve this issue.
Thanks. 

1.BIN

2.BIN

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Replies

  • Sune Nielsen September 8, 2015 at 2:32pm

    I also noticed that a short time before the nsats start dropping i am getting inaverr which rise to 255:

    3702088262?profile=original

  • Sune Nielsen September 8, 2015 at 1:49pm

    I am going test with compass mot tomorrow, but given the logs all show something similar to this:

    3702088649?profile=original

    Then it doesnt look like a compass issue. What I am wondering is what can cause it to suddenly loose gps'es like that?

  • Haygood August 31, 2015 at 6:06pm

    This sounds a lot like what mine did when I had two motors dying. Run the motors for a while and compare their temperatures either by touching them or with an IR thermometer.  

  • Coty Wood August 31, 2015 at 8:30am
    Have you looks at the results of a compassmot?
    • Keith Wolters > Coty Wood August 31, 2015 at 9:35am

      When calibrating the compass per the video I did not get very many dot'/positions. After talking to 3DR it was suggested that I calibrate with the Iris plugged in to Mission Planner witch gave me at least 5 times more. No real reason why that mattered but it works. Also I try not to fly till at least 8 sat's even though I get GPS lock earlier.

  • Paul August 31, 2015 at 7:59am

    I'm only a beginner, but i hope this can contribute to your issue.

    Could it be that you don't have enough sats?
    I'm counting sometimes only 6 (at the failure moment.)
    What I also miss in you bn file is the vibrations. Are they ok?

     

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