Hybrid supervision scheme for satellite attitude control with sensor faults

In modern aerospace engineering, fault-tolerant control (FTC) has become increasingly vital for maintaining spacecraft functionalities, including attitude control. The attitude determination module incorporates data from different sensors. Star trackers and gyroscopes provide attitude and angular rate measurements affected by noise. To minimize the latter, the so-called gyro-stellar estimator exploits optimal state estimation such as Kalman filters. However, gyros are subject to drifts which beyond some limits could affect estimator convergence. In this paper, a hybrid supervision scheme is proposed for attitude control affected by gyroscope faults. The data-driven fault detection and identification (FDI) module localizes and coarsely identifies the emerging drift. Then, the supervision system reconfigures the gyro-stellar estimator and updates the controller gains to guarantee FTC capability. The final hybrid system ensures attitude control function until fine-tuning is performed by attitude determination and control engineers. Simulation results with in-orbit data validate the effectiveness of the proposed approach.