改进的月球返回再入制导律

Modified Entry Guidance for Lunar Return Vehicles

月球返回舱高速返回地球,再入动能非常大,使得月球返回舱的再入制导精度难于得到保证。采用传统的制导方法很难同时满足精度、航程、过载和热量等要求。针对以上不足,为了设计一种安全、有效且适合大范围航程的再入制导律,结合解析预测制导和数值预测制导的优点,设计了一种改进的月球返回再人制导律。具体方法是在阿波罗解析制导方法的基础上,通过在上升段和弹道段使用数值预测校正算法(NPC)提高了纵程能力。又将决策权提前至初始滚转段,并采用变化的常值阻力加速度。仿真结果表明,改进设计的制导律提高了航程能力和落点精度,降低了过载和总热量,使动态性能得到改善,改进方法可为月球返回再入制导优化设计提供依据。

Lunar return vehicle returns to earth with high speed,it＇s kinetic energy is very large,which makes the reentry guidance of Lunar return vehicle more complicated and difficult.It is difficult for traditional method to meet the requirements for accuracy,range,overload and total heat.In order to design a safe,effective reentry guidance that is suitable for a wide range,we designed an improved lunar return reentry guidance law combining the advantages of analytical prediction guidance and numerical predictor- corrector guidance（NPC）.In this paper,through making use of NPC in Upcontrol and Ballistic based on Apollo guidance,the downrange capability was extended.On the other hand,Initial Roll hold the decision-making authority instead of Huntest,and changing constant drag was used. Results from Monte Carlo analysis show a significant advance in range capability and landing accuracy.Simulation indicates that the proposed algorithm can significantly reduce the overload and total heat and is a safe,effective method.