Attitude estimation with gyros-bias compensation using low-cost sensors

We present in this paper a new algorithm for attitude and gyro-bias estimation of a rigid body in rotation in space using low-cost sensors. The algorithm is based on sliding mode nonlinear observer that provides in the same time estimates of the gyro-bias and the actual attitude of the rigid body. This algorithm was developed in order to address the well-known problem of the weak dynamics of the attitude sensors (inclinometers), which can be modeled by low pass filters, and of the measurement bias of the gyros. In its design the observer uses biased gyro measurement and attitude measurements, provided by the low-cost sensors. The stability of the observer was proven using Lyapunov stability method. The effectiveness of the algorithm has been shown from experimental tests using a rotary platform equipped with several sensors with axes of rotation coincide with orientation of the rigid body.