Compass calibration in different hemispheres


I have a copter that is flying well on 3.6.10 in the northern hemisphere. I recently took a trip to the southern hemisphere, and I re-calibrated the compass upon arrival. After recalibrating in the southern hemisphere, I get a pre-arm warning: inconsistent compass. If I disable the internal compass the pre-arm warning goes away. Is there a setting that I am missing? The vehicle flew fine and did not exhibit the prearm warning when flying in the northern hemisphere.


Why did you re-calibrate the compass’s? Calibration is to correct for local (on the vehicle) mag interference. Declination, which is set to Auto by default, corrects for location and requires no user input unless you want to enter it manually.

Thanks for the info. I re-calibrated the compass because I added a different camera payload than I flew in the northern hemisphere.

OK, hardware change is a good reason to re-calibrate. Did the offsets of the internal mag increase significantly? I’m thinking that could account for it.

Not really, that is the strange part. Calibration was successful and uneventful, except for the pre arm message

Interesting you should bring this up.
I have completed a new build and was getting the same error no matter how many times I checked the compasses.
In the end I had to select only the external and disable the internal.
I was just think I had a fault in the setup somewhere that I would track down later.
Initially it would fail the calibration but eventually the calibrations went through on Default setting but arming still produced this inconsistent compass.

I am in the Southern Hemisphere.
Copter 3.6.10 will test again today on 3.6.11

Mike, thank you for the data point. I am pulling my hair out trying to figure out if I changed a setting or something else!