So I did some further testing again today and I think i may still have some issues.
If I set the USE MAGNETOMETER flag to TRUE, then the icon(psi value) will return back to the direction it was initialized at. Also if I initialize it with the board pointing north the psi value I read is 169 degrees, if I initialize when pointing west the psi value I read be with a few degrees of 169 degrees. Yet I can rotate the board and watch as the icon makes a full smooth 360 degree rotation.
If I set it to FALSE and AHRS USE GPS HEADING to TRUE the plane icon will initialize to 90 degrees. The icon rotates normally when I rotate the board but has the incorrect direction since the board always initializes to 90degrees on start up no matter the initial orientation. I'm assuming this won't be an issue in flight as the GPS has speed and can be used for direction.
I would really like to get magnetic orientation, primarily in high winds where a lot of strafing can occur.
How can I get an accurate Mag Heading that is completely independent of GPS?
Also is the IMU MAG message in messages after applying current calibration, magnetic deviation and magnetic variation?