Feasible footprint generation with uncertainty effects

Abstract

Landing footprint is critical in generating feasible entry trajectories for hypersonic glide vehicles. In this paper, a new landing footprint generation algorithm that considers multiple uncertainty effects is proposed, based on the improved 3D acceleration profile planning method. First, a new entry corridor with uncertainty effects is derived, in which the angle of attack profile is adjustable at any time during the entire flight. Second, the longitudinal drag profile is designed as the interpolation results of the upper and lower fitting safe boundaries. The corresponding lateral lift-to-drag corridor is obtained using the quasi-equilibrium glide condition. A combined Proportion Integration Differentiation (PID) tracker is used to follow the planned profiles in the longitudinal and lateral corridors, and the feasible entry trajectories are completed. Finally, feasible footprint is generated by repeatedly computing the reachable boundaries for all the profiles in the new safe corridor, as well as the analytical calculation of the maximum range point. The approach is tested using the Common Aero Vehicle-H model. Simulation results demonstrate that the proposed algorithm can rapidly generate a feasible footprint of entry for vehicles while satisfying all the path and terminal constraints.