月球探测器转移轨道的中途修正

月球探测器的中途制导指的是在其转移轨道中途对轨道进行修正，使其按预定轨道飞行。本文研究的中途修正问题是确定所需的速度修正脉冲，使探测器不断接近标称轨道，并以预定状态到达月球，完成预定的飞行任务。本文首先建立中途修正的模型，其中月球和太阳的位置由DE405得到。然后，采用精确的数值积分方法找出满足预定条件(近地点高度、近月点高度及转移时间)的转移轨道。以该轨道作为标称轨道，分析中途修正所需要的速度修正脉冲与发射入轨时的初始误差(近地点速度误差、入轨高度误差、发射窗口误差等)和修正时刻的关系。最后分析两次中途修正的速度修正脉冲和修正时刻的关系，并得出适合的中途修正时刻。

Mid-correction of trans-lunar trajectory of lunar explorer

The m id- guidance of lunar prospect usually refers to correct its trajectory on the way to the moon. The mid- correction problem treated here was to determ ine the velocity impulse required at a given midcourse cor- rection time in order to achieve a desire terminal state relative to the m oon.Ephem eris DE4 0 5 was use to determ ine the position and velocity of the moon and the sun.The m ethod was base on the precision num erical integral trajec- tory solution.Trans- lunar trajectory was found,which was regarded as the nominal trajectory and satisfied with scheduled conditions(such as height of perigee,height of perilune and transfer tim e) .Then,correction impulses of velocity relate to the error of velocity of perigee,the error of the height of perigee,the error of launch window and the tim e of correction are discussed respectively.Finally,twice m idcourse correction of trans- lunar trajectory is in- vestigated.The proper m idcourse correction time is given by constracting the two midcourse corrections.