Abstract:

A 3-D guidance trajectory algorithm of terminal area energy management (TAEM) for reusable launch vehicles (RLVs) is researched. According to initial and autolanding interface (ALI) dynamic pressure, a reference dynamic pressure profile is planned. Lateral reference trajectory planning includes two steps, that is, erasing the lateral position error and longitudinal position error. During erasing lateral position, the longitudinal error is beingreduced. According to the size of the longitudinal position error, three modes of trajectories are used to erase it by a set of logical procedures. Based on the reference dynamic pressure profile and lateral reference trajectory, a 3-D guidance trajectory is propagated by means of the longitudinal lateral coupling equations of motion. Simulation computations show that the trajectory algorithm can propagate a 3-D guidance trajectory fast, exactly and robustly. Therefore, it can be a candidate for onboard trajectory generation.