Abstract: To meet the requirements of precision strike of hypersonic vehicles in the diving phase, a trajectory planning method with terminal velocity and impact angle constraints is proposed. A two stage trajectory planning strategy is established. In the first stage, a parameterized control profile is used to adjust the flight velocity, and in the second stage, a bias proportional navigation guidance law is used for the impact angle constraint. The control profile parameters are determined by solving a multi parameter optimization problem and a single parameter searching problem. The multi parameter optimization is solved offline to maximize the feasible zone of the initial position, which improves the adaptability to initial errors. The single parameter searching with a penalty function is conducted onboard, which yields a constrained diving trajectory. The proposed trajectory planning method is verified by simulations using a hypersonic vehicle model. The results indicate that the method satisfies both the terminal velocity and impact angle constraints, has good computational performance, and is robust to the initial dispersions.

Key words: Hypersonic vehicles, Diving phase, Terminal velocity constraint, Impact angle constraint, Trajectory planning