Adds a 312 Euler rotation sequence option for magnetic heading fusion.
Switches between it and the normal 321 sequence option depending on orientation.
This method is more suitable than a raw heading measurement because it works across a full range of pitch angles.
It has been made the default for ground operation.
This bug was in the derivation and resulted from use of a tan instead of an atan operator. The derivations have been reworked and the updated auto-code has been imported as part of this patch.
When fusing 3-axis magnetometer data without absolute external aiding leg GPS), the declination is ultimately unobservable and the declination of the field states and the vehicle heading will slowly drift over time. To prevent this we need to fuse in a declination to constraint the NE earth field estimates.
Set conservative defaults as a baseline for tuning
Add a missing parameter for magnetometer observation noise.
Correct error in definition of magnetic heading observations noise (previous parameter defined the variance directly, not the noise).
Scale vertical GPS noise to allow for average EPV to EPH ratio.
Update documentation and display names for consistency.
