Initial Descent Phase Guidance for Hypersonic Glide vehicle

A novel initial descent guidance law based on the transition function is proposed for the hypersonic glide vehicle without offline nominal angle of attack (AOA) design and online iteration process. Considering the variation of the gravitational acceleration, a new transition condition between the initial descent phase and the quasi-equilibrium glide phase is deduced. Afterwards, the initial descent phase is divided into two sub-phases noted as the open-loop guidance phase and the transition scheme phase. The guidance command during the transition scheme phase is generated by transition functions firstly proposed in this paper, which can smoothly adjust the AOA to satisfy the transition condition. The simulation results show that the proposed guidance law can satisfy the transition condition and the path constraints.