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'm sure there are people here who can guess what's happening...


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


TCIII ArduRover2 Developer

Yes Thomas, I did it serveral times. The problem is that I get high values in the compass calibration (-184, -155, -23), even if I perform it with the APM board only - no batteries, frames or any EMI close. That's is what is surprising me and this is why I',m asking for help

Are you outside, away from magnetic sources like conducting cables etc when you calibrate

I'm at home, but I tried to do it as far as possible from electronic devices. But watching the video on the arducopter site of how to do the compass calibration, he does it in a room with a pc, wire, etc.... their values are about 30 (don't remember so well), much less than mine.... anyway, I'm going to try it again in a less magnetic environmental and I'll let you know.


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



I'm having the same problems with an external compass. Whatever I do, I'm still getting offsets above 150. Let me know if buying a new one help fix the issue. 



Are you having problems with external or with internal compass? My external is on its way, I’ll let you know when I have it

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 field....no not the baseball field (chain link fence screw things up like you would not believe)!\

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

Hi Rick,

I don't think is a GPS problem, but thanks. Yesterday I uploaded the version 3.1. I don't exactly know the changes, but now my loiter is awesome... I haven't done anything else but uploading the new version and the first impression was incredible.


that was my next suggestion was just to reload the current version. I have done that once and was like what nothing changed not even the version I uploaded and was amazed at stabilization! It must have had a glitch in it somewhere. It happens even with a good update...



Good to hear!

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.

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