Rapid generation of landing footprint based on geometry-predicted trajectory

Abstract

Landing footprint is critical to generate a feasible trajectory onboard for entry vehicles. In this paper, a new landing footprint calculation based on geometry-predicted trajectory is proposed. First, the lateral motion states, turning radius and angle, are analytically solved based on a planned drag acceleration vs. energy (D–E) profile. Through some simple coordinate and geometrical triangle transformation, all the trajectory states are extracted. Second, by calculating the maximum longitudinal range point, the furthest reachable boundary for planned D–E profile is obtained with proposed geometry-predicted trajectory. Finally, the landing footprint can be generated by repeatedly computing the reachable boundaries for all D–E profiles in the entry corridor. Simulation results with Common Aero Vehicle (CAV) model validate the accuracy of the geometry-predicted trajectory. Furthermore, detailed comparison of footprint generation results between the traditional and the proposed are presented at last.