采用格林函数法,导出了最优再入轨迹的三种过程约束(气动加热率、动压、升力约束)条件之间关系的近似定量描述。求解了航天器同时受三种约束条件时各种性能指标下的最优再入轨迹的近似解,及相应的最优控制规律。通过对近似解与控制规律的结构分析,得到了一些重要的结论。 Using Green’s function method, the approximate quantitative description of the relationship between the three process constraints (aerodynamic heating rate, dynamic pressure and lift constraints) of the optimal reentry trajectory is derived. The approximate solution to the optimal reentry trajectory under various performance indexes and the corresponding optimal control law are obtained when the spacecraft is subjected to three kinds of constraints at the same time. Through the structural analysis of approximate solution and control law, some important conclusions have been obtained.