Velocity-Free Guidance Scheme for Close-Range Rendezvous

A novel multiple-input-multiple-output(MIMO) guidance scheme is proposed for reliable spacecraft rendezvous in the presence of external uncertain disturbance in this paper. To estimate the unknown relative velocity between the chaser and the target in real time, a novel finite-time convergent observer based on second-order sliding mode theory is proposed. Next, a MIMO guidance scheme based on super-twisting control theory is proposed to drive the relative range and its rate converge to a small compact region around zero in finite time. The stability of the closed-loop system is verified via Lyapunov theory. The results of numerical simulation demonstrate the effectiveness of the proposed guidance scheme.