Anti-Disturbance Attitude Tracking Control with Practical Prescribed-Time Convergence for Rigid Spacecraft Subject to Measurement Noises

In this paper, an observer-based attitude tracking control scheme with practical prescribed-time convergence is investigated for rigid spacecraft in the presence of measurement noises and external disturbances. To address the challenges posed by mismatched disturbances, two filter-based disturbance observers are designed. Building upon the disturbance observers and employing the sliding mode control technique, the practical prescribed-time controller is developed to ensure that the attitude and angular velocity converge to a desired region within a prescribed time. Compared with traditional prescribed-time control methods, the key feature is that the convergence time and precision can be independently designed. Furthermore, a comprehensive stability analysis over the entire time domain of the closed-loop system is conducted, which provides a rigorous foundation for the proposed control scheme. Simulation results are given to validate the effectiveness of the control strategy.