卫星激光测距通过测量激光脉冲在地面观测站和卫星之间的往返时间来计算卫星到测站的距离.激光反射器位置到卫星质心的距离即质心改正(CoM)需要精确标定,以提高卫星测距精度.卫星激光反射器的质心改正误差主要由角反射器分布效应引起,质心改正与激光束的入射角、角反射器排列结构和地面测距站位置有关.卫星角反射器对光子的反射概率与反射器的有效雷达截面积成正比,本文对角反射器的有效雷达截面面积进行拟合,建立以入射角为随机变量的概率模型,计算了球形LAGEOSG1/2的质心改正值,基于长期观测数据使用不同质心改正值进行了精密定轨,分析了其加权残差变化.同时,对BeiDou-M3的角反射器为平面阵列的情况进行了讨论,计算了质心改正值,用一个月的数据进行精密定轨.试验结果表明,基于概率理论的模型在精密轨道中与国际激光测距服务(ILRS)公布的结果相当,说明概率模型适用于球型卫星或非球型卫星.
Satellite laser ranging system calculates the distance from ground‐based observatories to satellites using the round‐trip travel time of laser pulse.The position of retro‐reflectors on satellites needs to be corrected which is helpful to improvie the measuring precision of satellite laser ranging.The correction errors of center‐of‐mass(CoM)are mainly caused by the distribution effects of retro‐reflectors on satellites. CoM is related to incident angle,structural alignment of retro‐reflectors and ground‐based position.Based on the reflecting probability of photons for retro‐reflectors is proportional to the cross sections of retro‐reflectors,the cross section area of corner reflectors is fitted and the probabilistic model is established using incident angle as the random variable.The corrections of CoMs of spherical satellite such as LAGEOS‐1/2 are calculated and different CoMvalues are applied for SLR precise orbit determination using long‐term full rate observation data with different WRMS results analyzed.At last,for the planar array ret‐ro‐reflectors,the CoMs of BeiDou navigational satellite such as BeiDou‐M3 are also calculated and analyzed using one month SLR full rate data.The result shows that the calculated CoMs based on probability theory have the comparative precision in SLR precise orbit determination.