Observer and first-order low-pass filter based attitude estimation for rigid bodies subject to external acceleration

In this paper, we consider the problem of estimating the attitude of a rigid body who is subject to non-negligible external acceleration, based on the measurements provided by a classical IMU unit: gyroscope, accelerometer and magnometer. Two algorithms are proposed, based on the combination of a low-pass filter in the fixed inertial frame and an observer. The stability of the proposed schemes are proved, based on a Lyapunov approach. Simulations are provided in order to illustrate the performances of the proposed observers.