为了获取高精度的月面高程,需要对激光器的指向误差进行准确估计。月球轨道激光高度计(LOLA)在轨工作期间,由于月球昼夜温度相差较大,夜晚的激光指向相对白天存在很大偏移。首先建立光斑偏离接收视场中心时探测器接收能量的理论模型,并基于该模型分析光斑偏移量与相对接收能量的理论关系,进而提出一种基于光斑能量的激光指向误差的估算方法。随后,使用测绘轨道期间(12个月)LOLA经过Aestuum地区产生的能量数据,并将能量数据与估算方法相结合,估算出LOLA在月球夜晚时的激光指向误差在沿轨方向为140.62 μrad,在垂轨方向为-413.17 μrad,该结果与LOLA地球扫描实验和利用轨道交叉点处高程数据推导的结果基本一致。

To obtain the moon elevation with high accuracy, it is necessary to accurately estimate the pointing error of laser. During the on-orbit operation of the lunar orbital laser altimeter (LOLA), the laser pointing at night deviates from that during the daytime due to the large temperature difference between day and night. This study first establishes a theoretical model of the detector’s received energy when the spot deviates from the center of the receiving field of view. Then, it analyzes the theoretical relation between the spot’s offset and relative received energy based on this model, and puts forward a laser pointing error estimation method based on spot energy. Subsequently, using the energy data generated when LOLA passed through the Aestuum region during the mapping orbit (12 months), this energy data is combined with the proposed estimation method, and laser pointing errors of LOLA at night in moon are estimated to be 140.62 μrad along the orbit direction and -413.17 μrad in the vertical orbit direction, which are consistent with the results derived from LOLA earth scanning experiment and orbital intersection altitude data.