Compass offsets


I don’t know if anybody can help me or at least explain this. I had problems with the loiter (the typical toilet-bowling) so I took a look at the compass offset values. They were -175 -158 -13, out of the recommended range (-150 150), so I decided to rearrange the hardware of my quad as some of you recommended. To have a reference of how much I can improve these values, yesterday I did the live compass calibration with the APM alone, without the frame, batteries, ESC, etc. Only the APM board (and a USB cable), away from any EMI source and metals, and surprisingly the values were -184, -155, -23. I repeated the live compass calibration several times but the values didn’t change so much :(

so… What can I do??


If this helps, I have checked old logs and I had had similar values of the compass offsets always! But the loiter was fine, not amazing, but fine.

I’m currently using APM 2.5 with firm 3.1-rc5 (the one with auto-tune).


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  • I think the best is to desactivated all inboard compass and check extern compass and check use external for primary.

    I try neo 8m and a Neo M8n and same results so I really think it's inboard problem.

  • Hi, is this problem solved? I am having a very similar issue with my APM. When I calibrate the internal compass everything is OK, but when I disable it and try to calibrate the external one the z axis is too high (can't bring it lower than 450).

    My GPS is the NEO-M8N, I've tried calibrating it many times indoor and outdoor but none of that works.

    Does anyone knows how to solve this?


  • I too am having the same problem. I can't get the "z"value less than 190. X is around -44 Y is +22 and z is anywhere from 190 to 215. I've tried it indoors, outdoors away from metal objects and it doesn't make a difference. I'm running 3.1 fw. According to the documentation, it won't arm if the numbers are greater than 150. I just upgraded the board to the external gps and compass. I did cut the trace as well.
    This is getting frustrating.
    • Did u find solution?
      I have the same issue:
      Test: Compass = FAIL - Large compass off params (X:-158.94, Y:115.60, Z:8.33)
      No MAG data, unable to test mag_field interference

      My system: APM 2.6, external compass LEA-6H GPS
      Mission planner settings: External compass ROLL 180

      Latest firmware.

      Compass & mag are connected high in a middle

      Any idea?

      • I didn’t find a solution. I bought an external compass and now is working perfectly.

        I don’t understand quite well you problem, you don’t have magnetic field data but you have offsets… weird.

        I had a similar error (no MAG data) when I didn’t connect the external magnetometer correctly. Check the connections, I don’t know what else to say

        • I have this:

          This is how my quad fly:

          My onboard module dont have compass so thats why I need GPS & compass external.

          As you can see from video it's mounted far/high away from any electric device.

          When I try to calibrate indoor with powered only apm & compass i still getting the same results. My X offset is too far away from normal -157. And LOG Diagnoss shows Compass check FAIL because of that Offset - and thats why it will not log mag data.

          Compass still looks like its working, but i dont know how good is it working.

          As video see loiter and seems working.

          So if anybody has an idea - please.

          Is it maybe hardware issue or something esle?

          I'll also attache my logs.

          And by the way my YAW looks also weird - when i try to use YAW copter looks like fall one side and the try to turn and the first move, than turn fine. Any idea?

          Maybe somebody can take a look my logs to make sure everything works fine.



          2014-06-02 20-35-47.log

          • I'm pretty sure it is a hardware problem cos the same happened to me. My loiter had problems some times and few times even the stabilized was not working well (it wasn't a big problem, it wasn't horizontal and I had to stabilized by myself). But if in your case is working, I would do nothing.

  • did you get this solved?

    Did you have good signal and line of sight to as many satalites as possible BEFORE starting the calibration?

    I know I can use a hand held GPS and walking in an open field and watch the sats come and go and nothing is around for 200 yards in either direction...just the nature of the beast. Also reflection and refration of the signals durring calibration will give bad readings too. Take out your laptop and just the compass and go to a not the baseball field (chain link fence screw things up like you would not believe)!\

    Guess I should have read the comments before posting...

  • This weekend I went to fly and I did the live calibration, away from any magnetic source and with the telemetry. The results didn’t change so much: 178/155/-28. This time I didn’t get the toiletbowl, but I think my magnetometer has something wrong, so I already purchased the external. I hope is going to working better :)

    Thanks for your help


  • Admin


    Have you performed the compassmot as well as the compass calibration?


    TCIII ArduRover2 Developer

This reply was deleted.


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