大 气 层 内 动 力 下 降 段 的 组 合 干 扰 补 偿 制 导

The reusable rocket recovery landing in the atmosphere uses aerodynamic force and thrust to complete a high-precision pinpoint vertical soft landing. In the powered descent phase，there are various disturbances such as thrust deviation，aerodynamic model deviation and wind disturbance，which will reduce terminal landing precision and influence the performance indicator. The guidance system faces the difficulty of disturbance rejection. To solve this is⁃ sue，a combined disturbance compensation guidance method is proposed，which divides the disturbances into model⁃ lable and unmodellable disturbances according to whether they can be described by modelling. These two types of dis⁃ turbances are processed separately. Modellable disturbances are considered to be used for optimal guidance to im⁃ prove the performance indicator，while unmodellable disturbances are used to compensate their adverse effects on the terminal constraints in real time. In the combined disturbance compensation guidance framework，firstly，a disturbance estimator is designed to estimate the two types of disturbances in real time. Then，a neighboring optimal disturbance compensation guidance algorithm is designed to correct and compensate the optimal guidance command in real time by using the estimated values of modellable disturbances，so as to improve the performance indicator using model⁃ lable disturbances while ensuring terminal constraints. Finally，a terminal invariance disturbance compensation guid⁃ ance algorithm is designed to ensure terminal invariance by calculating the terminal constraint perturbations caused by unmodellable disturbances and compensating the adverse effects of unmodellable disturbances on terminal constraints in real time. Simulation results show that the proposed method can improve the performance indicator while ensuring the terminal landing precision，and has strong robustness to various disturbances.