How to calibrate magnetometers outside?

Yes, I know about: copter.ardupilot.com/wiki/ac_com … ss_offsets

The question is, how do you do it outside ? - I use Andropilot and Droidplanner, none makes compass calibration accessible, am I missiong something ?

Well, I live 1st floor, so I put the copter in the garden, go back inside, start the calibration on the PC and rush out…
Alternatively, you could hire your girl-friend/wife/etc. to click the button when you are outside.

PS:[mf]Copter/3.1[/mf]

I wouldn’t think that re-doing the calibration should be important. The compass calibration calculates the offsets that are caused by metal objects on the frame or in the board. These shouldn’t change based on your location.

The bits that do changed based on your location are the declination, inclination and magnetic field strength. If you have the AutoDeclination set to true (it’s on the compass calibration page in the mission planner) then that will be looked up automatically from a lookup-table using your GPS location.

The inclination and mag field aren’t anything that we can do anything about and shouldn’t affect the heading in any case.

So basically I don’t think that it should be necessary to re-do the compass calibration.