A mixed extended-unscented filter for attitude estimation with magnetometer sensor

A priori information given by the complete modelling of the ballistic behavior (trajectory, attitude) of a projectile is simplified to give a pertinent reduced evolution model. A new mixed Kalman filter based on Extended and unscented Kalman filter is designed to estimate 3 attitude angles from measures of the magnetic field of the Earth given by a three-axis magnetometer sensor embedded on the projectile. The algorithm has been tested in simulation, using realistic evolution of attitude data for a shot with a 155 mm rotating projectile over a distance of 16 km, with wind and measurement noise. The results show that we can estimate milliradians with non-linear equations and approximations, with good accuracy