Rapid trajectory planning for hypersonic vehicles

We present a rapid online trajectory planning methodology for hypersonic vehicles´ gliding flight, where the situations may change and new missions designated. The trajectory planning algorithm employs an analytical method yielding feasible trajectory satisfying all the flight constraints. In this problem, a parameterized altitude vs. velocity profile is designed according to initial conditions and trajectory constraints. A ground track is designed based on the endpoint constraints on position and heading. Then the associated turning radius is calculated analytically. These can yield an angle-of-attack and bank angle profiles analytically by taking Quasi- Equilibrium Glide Condition(QEGC) into account. Then we use an iterative algorithm to adjust the designed variable in altitude vs. velocity profile to satisfy the terminal constraints. In numerical simulation, the vehicle is guided from an initial positions to an endpoint planned before. Simulation results suggest that the trajectory planning method is effective and accurate enough for an emergency.