A globally stable scheme for Spacecraft control in the presence of sensor bias

In this paper we developed a globally stable scheme for bias estimation in the case of attitude stabilization. Our scheme is based on the development of nonlinear observers for bias identification and state estimation. In the case of gyro bias, our nonlinear observer design is based on the angular velocity dynamics. It is shown that a suitable parametrization leads to an error model and adjustment laws that result in guaranteed asymptotic convergence of the state estimation error to zero. This, in turn, assures that the stabilization objective is achieved asymptotically. The efficacy of the algorithm is illustrated through numerical simulations.