卫星形状效应是阻碍卫星激光测距(SLR)系统测距精度向毫米级发展的重要因素之一。基于卫星角反射器的实际分布,提出了角反射器不均匀分布(RUD)模型,计算了激光入射角与参与SLR过程的卫星角反射器个数、分布、反射强度的关系,分析讨论了卫星形状效应对SLR回波数据残差分布、卫星质心改正(CoM)值产生的影响。结果表明,与现有CoM模型不同,利用RUD模型计算得到的参与SLR反射的角反射器个数随激光入射角变化,角反射器分布分散且不对称,同纬度各角反射器反射激光强度不同,SLR回波波形中“拖尾效应”明显,与实测结果相符。同时,利用RUD模型得到的CoM值随激光入射角呈动态变化。对于Lageos-1卫星,长春站CoM平均值为248.1 mm,在国际激光测距服务组织的参考范围之内。

The millimeter accuracy of a satellite laser ranging (SLR) system is often hindered by the satellite signature effects. Based on the actual distribution of the satellite retroreflectors, the retroreflector uneven distribution (RUD) model is proposed in this study. The relationships between laser incident angles and the number, distribution, and reflection intensity of the retroreflectors that have participated in the SLR reflection are calibrated and discussed, while the effects of satellite signature on the echo signal residual and center-of-mass correction (CoM) are analyzed in detail. Results indicate that compared with the common CoM model, the participant retroreflectors are dispersedly and asymmetrically distributed, and their number is a function of laser incident angles. The reflection intensity for each reflector at the same satellite latitude is different and the retroreflected pulse is observed to be broader than the transmitted pulse with significant tailing effect. The above results agree with the experimental results. In addition, the CoM value obtained using RUD model dynamically varies with the laser incident angle. For Lageos-1, the average CoM of Changchun Station is 248.1 mm, which is consistent with the reference range accepted by the international laser ranging system.