Now I have another question about the calibration model described in AN4246, I doubt it realy can calibrate the non-orthogonality error matrix?
According AN4246 Eqn.4, Soft-Iron Model constains Soft-Iron effect?magnetometer gain effect and non-orthogonality effect,the non-orthonality matrix can be used to model 1:the rotation of the magnetometer sensor relative to the smartphone coordinage system,2:the lack of perfect orthogonality between sensor axes.
My calibration process:Rotate PCB in 3D space, try to make magnetometer in PCB traverse each attitude.
then the measured geomagnetic data will be the input of the calibration model of AN4246,then I can get Soft Iron matrix(A) and Hard Iron matrix(b).
Calibration Result
Soft Iron Matrix and Hard Iron MatrixBut in this calibration process,PCB and magnetometer is rotating together,the relative axis non-orthogonality between them have no effect on the measured data.No matter how the magnetometer axis deviation from the PCB axis,the measured geomagnetism data will be the same ellipsoid.
So I wonder if I misunderstand the calibration model in AN4246, or there is something wrong about my calibration process?