Hey!

I tried this compensation algorithm with the magnetometer readings of my navigation app. This is the update method I have:

void update()
{
    var r = Reading;
    r = MagneticCompensation.Compensate(r);
    Algorithm.Update( /* (Madgwick) */
        (float)r.gX, (float)r.gY, (float)r.gZ,
        (float)r.aX, (float)r.aY, (float)r.aZ,
        (float)r.mX, (float)r.mY, (float)r.mZ);
}

where m is the magnetometer readings.

As the magnetometer values are given in this form to the madgwick sensor fusion algorithm I did not understand what the after-following matrices does - and if they are necessary?