Rapid terminal area trajectory planning for reentry vehicles

Achievements of the Space Shuttle experience and recent research activities were analyzed and absorbed, and a rapid generation technique of trajectories was focused on for the terminal area of reentry runwaylanding flight vehicles. Based on the present processing capability of onboard computers, the trajectory geometry preset planning can be replaced by logic condition based algorithms which can represent the flight dynamics, so that the accuracy and rapidness can be better compromised. In view of the separation of the variation time scales, a propagation logic without iteration was established for longitudinal variables, combined with lateral effect correction. For the lateral motion, a three-step logic was put forward compromising the flexibility and effectiveness. Testing cases from different initial conditions show that the algorithm is promising for onboard application. It can rapidly generate trajectories with satisfactory accuracy due to the incorporation of the coupling effects in flight dynamics, and the guidance commands can be tracked by basic guidance control law.