Abstract: To enhance the accuracy of reentry guidance, an improved predictor corrector guidance algorithm is presented by introducing a piecewise objective function. In the early stage the function is defined as range to go while in the terminal stage as drop point error.The modified objective function can generate not only the amplitude but also the symbol of the bank angle without the cross range corridor so as to guarantee the computational efficiency as well as the guidance accuracy. Furthermore, the no fly zone avoidance is taken into consideration. In addition to classifying the no fly zone into two types, an amplitude correction mechanism is employed to cope with the situation where the no fly zone cannot be avoided only by the bank angle reverse strategy. The Monte Carlo simulation with random initial dispersions and model uncertainties demonstrates that the proposed algorithm is effective on no fly zone avoidance and has higher guidance accuracy than single objective function method.

Key words: Aerospace vehicle, Re entry guidance;No fly zone avoidance, Piecewise objective function, Predictor corrector guidance