On-line Trajectory Generation Based on Approximate Analytical Solutions

摘要

This paper presents an on-line trajectory generation method based on approximate analytical solutions. Based on a unified formula of inequality path constraints, a series of approximate analytical solutions considering the effects of Earth rotation and drag coefficient rate are derived. Further, the entry trajectory is divided into four phases and each phase is parameterized by one parameter, reducing the algorithm complexity. In addition, the path constraints can be satisfied by limiting the range of these parameters. Using the parameterized trajectory, the on-line trajectory generation problem is divided into two sub-problems: the longitudinal trajectory sub-problem and the lateral heading sub-problem. The longitudinal trajectory sub-problem is solved through sequentially searching the four parameters; the lateral heading sub-problem is accomplished through searching a bank reversal point with the help of the analytical solutions. And then, a trajectory generation algorithm is devised to meet the terminal design requirements of range to go and lateral heading. Simulation results of different orbital entry missions demonstrate that the proposed method is of satisfactory adaptability.