Predictor-corrector guidance for entry with terminal altitude constraint

A novel predictor-corrector guidance algorithm is presented for the entry flight with the terminal altitude constraint. Previous predictor-corrector algorithms focus mainly on the flight range control, thus the terminal altitude error is large in dispersed cases. To improve the guidance precision of the terminal altitude, both the bank angle and the angle of attack are utilized as control variables in this study. Considering the computational performance, a simple profile update method for the two control variables is designed, and a trend control approach is employed by the corrector. Simulations are conducted on an entry flight in the nominal case and dispersed cases. Results show that the proposed method is robust to the initial and aerodynamic dispersions. Compared with the conventional method, the proposed method achieves similar terminal range precision and much higher terminal altitude precision.