Adaptive guidance for spacecrafts autonomous rendezvous with aspect constraint

Guidance and control strategies for terminal proximity of autonomous rendezvous with constrained aspects are researched. The relative dynamic equations described in the local orbital frame of the target vehicle are transformed to the line-of-sight(LOS) frame. The rendezvous controllers along LOS and perpendicular to LOS directions are designed respectively. To satisfy the requirements on relative positions and velocities in the rendezvous, an adaptive controller in the LOS direction based on zero-effort-miss (ZEM) is derived. Then a modified proportional navigation guidance law with LOS angle constraint is adopted to control the proximity angles. The controllers can be implemented only using the relative motion information between rendezvous vehicles and are not sensitive to the initial conditions. Numerical simulations for the target both on circular and elliptical orbits are given to validate the feasibility of the control strategies.