Speed Constraint Deceleration Guidance Method for Reentry Gliding Vehicle

Focusing on the speed control degradation of reentry gliding vehicles during terminal guidance phase due to model uncertainty such as aerodynamic parameter perturbations, a robust bias proportional navigation guidance law with speed constraint is proposed. This guidance law can satisfy the accuracy requirements for target interception and the terminal speed constraint of reentry gliding vehicle, and has robustness against uncertainties such as perturbations in aerodynamic parameters. An error dynamics model of flight speed and ideal speed curve is established based on the control strategy of additional angle of attack deceleration. By introducing the theory of fixed-time convergence error dynamics and considering the model uncertainty caused by the perturbations of aerodynamic parameters during the flight, a speed constraint guidance law based on the fixed-time convergence error dynamics is derived. It is also proven that the speed error dynamics is converged under the bounded model uncertainty. The performance of the proposed guidance law is validated through numerical simulation, and its robustness against initial parameter and aerodynamic parameter perturbations is also verified through Monte Carlo test.