月球探测器转移轨道的中途修正

Mid-correction of trans-lunar trajectory of lunar explorer

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 DE4 0 5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 [1 ] 。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。

The mid-guidance of lunar prospect usually refers to correcting its trajectory on the way to the moon. The mid-correction problem treated here was to determine the velocity impulse required at a given midcourse correction time in order to achieve a desire terminal state relative to the moon. Ephemeris DE405 was use to determine the position and velocity of the moon and the sun. The method was based on the precision numerical integral trajectory 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 time). 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 time of correction are discussed respectively. Finally, twice midcourse correction of trans-lunar trajectory is investigated. The proper midcourse correction time is given by constructing the two midcourse corrections.