月地返回轨道误差分析和第一次中途修正时机

分析了月地返回飞行过程中的误差因素和量级采用蒙特卡洛法和统计理论,定量分析了月地返回轨道入轨时刻误差、入轨状态误差、入轨控制误差、转移段定轨误差、中途修正控制误差等各种误差对轨道终端参数的影响。给出了月地返回轨道中途修正的计算步骤,然后以预期再入时刻和目标再入点为修正目标,采用微分改正法计算中途修正所需的速度增量。结合误差分析结果和测控条件,给出第一次中途修正时机的建议和一个具体算例,计算结果表明所提中途修正方法和策略可以修正入轨误差、定轨误差和控制误差的影响,使月地返回轨道可以按预期的再入时刻返回预定再入点。

Error Analysis of Moon-to-Earth Trajectory and Choice of the First Midcourse Correction

The error factors and their level in the flight of Moon-to-Earth trajectory were analyzed . Based on a specified Moon-to-Earth return trajectory , Monte Carlo method and statistical theory were used to quantitatively analyze the impact of the main errors on the terminals of the orbit including time bias and position error of transearth insertion （TEI）, orbit control error , orbit determination error and midcourse correction error , and etc.The calculation steps of midcourse correction of Moon-to-Earth trajectories were given .Then using the specified reentry time and the reentry point as the correction targets , differential correction method based on linear perturbation was adopted to calculate the veloci -ty increment of the midcourse correction .Then combined with measurement and control conditions , the first maneuver opportunity of midcourse correction was determined and a specific sample was giv -en.The results show that the midcourse correction method and strategy suggested in this paper can well amend the influence of the TEI error , orbit determination error and orbit control error .The Moon-to-Earth trajectory can return to the specified reentry point at the expected reentry moment .