Variable Horizon Reentry Guidance Based on Predictive Control and Pseudospectral Method for Hypersonic Vehicle

A method based on variable horizon predictive control is proposed in the paper for nominal trajectory guidance. Firstly, a feasible reference trajectory is generated by the Gauss pseudospectral method. Then, curvature is employed to represent the smoothness of obtained trajectory and predictive horizon is selected according to the curvature. Different predictive control optimal problems are established with different predictive horizon and the state variables of actual trajectory obtained in the last period are chosen as the corresponding initial condition. To reduce the computation burden, the optimization problem is also solved by the Gauss pseudospectral method. And the actual trajectory is gained by means of the control variables. The theoretical analysis and simulation results are conducted to illustrate that the proposed guidance law is effective and it could be benefit to improve tracking accuracy.