Abstract: Due to the traditional terminal area energy management (TAEM) guidance methods for a reusable launch vehicle (RLV) showing low precision and poor robustness, a 3D guidance strategy with real time correction is proposed for improving the guidance performance in terms of precision and robustness. Firstly, the RLV time domain based guidance model is transformed to the altitude domain based dynamic equations. A sliding mode guidance law is designed to generate the RLV trajectories and guidance commands in the presence of hybrid constraints. The guidance command is then regarded as the input of the time domain based guidance model. After a guidance period, the command is updated according to the current flight states against the influences of the disturbances on aerodynamic, atmosphere, and vehicle mass. Simulation results show good performance of the proposed guidance method.

Key words: Reusable launch vehicle (RLV), Terminal area energy management (TAEM), 3D robust guidance trajectory, Sliding mode guidance law