Trajectory optimization for terminal phase flight of hypersonic reentry vehicles with multi-constraints

The trajectory optimization method for terminal phase flight of a hypersonic reentry vehicle is studied. In addition to the constraints on the final position coordinates, the final impact angle and velocity are specified, and the vehicle´s attitude stabilization and the operational effectiveness when impacting are considered. The trajectory optimization problem is formulated as the multi-constraints optimal control problem. Via Radau pseudospectral method, it is converted into the nonlinear programming which is solved by SNOPT. Two different types of optimization missions are considered and simulation results verify the validity of the method. The optimal flight strategies are obtained and analyses of the difference of the results between different conditions are made. The research in this paper can also provide helpful references to mission planning and guidance for terminal phase flight of hypersonic reentry vehicles.