Pazz said:Nope, What you are referring to is Declination ( local magnetic interferences) . Thats what compass calibration Zeros out. Deviation(or variation) is the difference between True north & magnetic north, which varies depending on location & time (as it drifts over time) Compass calibration does not correct this.ianwood said:Either some of us have different definitions for deviation or people might be getting a little confused. The compass calibration that you currently do is for deviation. It measures a full circle in two axes to get the "background" magnetic fingerprint. That includes all your gear that you've stacked onto your Phantom and the environment you happen to be flying in.
Other than local field calibration, there is no other way to compensate for deviation.
Andy, depending on which Android device you have and how old it is, it could be using GPS derived course which is only determined after you establish a clear pattern of motion. Or, it is using an internal compass in your phone.
Suspect now the issue may be the fact the GPS is set to reading true north values ( same as a map) & the compass magnetic north values. However can you explain the dynamic relationship, in the auto pilot of the NAZA software, of the GPS, compass & barometer. are they connected?, do they give positive feedback or do they operate independently ?ie. gps for position, compass for heading & barometer for height. Do you have any insight it to the science behind how an auto pilot system works, as there seems to be very little material on this on the net.
You have the definitions of declination and deviation completely confused. Declination is, as repeatedly stated here, the difference between true north and magnetic north, while deviation refers to local field variations.
Your interpretation of the problem is likely sort of correct, but then it has been the entire topic of this thread for several months. Once again, you really need to read before posting.