Abstract: A midcourse guidance algorithm considering zero effort interception and angle of sight constraints is proposed to solve the problem of near space defense. Firstly, based on the zero gravity difference model, the zero effort interception condition of mid terminal shift is analyzed, which can be used to transform the endpoint constraint. It provides a simpler idea for multi constraint midcourse guidance design. Secondly, by introducing the spectral representation of the control commands and the low dimensional weighted matrix, the generalized quasi spectral model predictive static programming algorithm under time fixed is derived. Otherwise, the Legendre pseudo spectral method and adaptive Gauss Lobatto integral method are combined to improve the efficiency of the algorithm. Finally, the algorithm is used in the guidance design. The simulation results show that the midcourse guidance law proposed in this paper can satisfy the zero effort shift constraints, the control cost is smaller, and the guidance accuracy and calculation efficiency are higher. In addition, the midcourse guidance law under the premise of meeting real time requirements, has a stronger robustness to the initial state disturbance and parameter perturbation by the Monte Carlo simulation.

Key words: Midcourse guidance, Zero effort interception, Mid terminal shift constraints, Model predictive static programming, Legendre pseudo spectral method, Adaptive Gauss Lobatto integral