Safe Approach Trajectory for Rendezvous1

Based on some special points of the flying trajectory, this paper proposed a new safe trajectory design method for the approach phase of rendezvous and docking under arbitrary initial states outside the Keep-Out-Zone. Five types of approach trajectories were presented via analyzing the solutions of the CW equation. Then, the evolving laws of the relative position in X direction for the characteristic points of the trajectories were present. Through solving monotonous nonlinear equations, the evolving laws were used thereafter to deduce the restrictions satisfied for the safe trajectory, which provided the sufficient and necessary conditions for the safety of the trajectories. Simulation results demonstrate that this trajectory design method is simple and effective.