3.4rc6 Check mag field error

After compass calibration and compass mot went to the filed for a test. “check mag field” all over. Reset compassmot and all went fine. Back at home 100% mag field interference … maybe normal.
Autotune went perfect , stab, althold, loiter like butter! Will try a mission in the evening.
Many thanks to all devs!

I’ve been having really bad compass issues on my property…
If I arm the copter in my house and go to one side of the house, it fly’s fine. But then somewhere else, the compass starts pointing the wrong direction. (Copter facing north, compass facing north west). Sometimes I take off and immediately the EKF goes red because of the compass.
Yesterday I lost a copter because of it :(. It went crazy once I got about 10 feet off the ground. I managed to land it in my street, and as I was walking towards it someone ran over it!! both tires! Smiled and looked at me and said “sorry” while doing it!! WHY couldn’t they stop??? even after one tire, I’d stop my car if I was crushing something, but instead they decide to keep running over it and wave at me!! But anyway… I digress…

I finally had enough and grabbed my camping compass and walked around my yard… and wow, in some places in my yard the needle doesn’t point north! On some places on the ground, like where I armed the copter yesterday before the crash, the needle pointed southwest! I have no idea what’s going on here, but my yard has some magnetic anomalies.

I guess my point is, I think it is normal to need to redo the calibration depending on your flight location.

The only thing is I think it may not help to do the compass calibration at the new location. The compass calibration really only deals with metal bits that are on the vehicle. It doesn’t help with the interference that’s in the ground. We have a database inside ardupilot which handles the “declination” … and we also reset the compass once about 1.5m above ground to try and deal with metal bits that are right below the copter (i.e. when taking off from a metal ship).

Thanks for the feedback and helping with beta testing!