Effect of Atmospheric Turbulence Anisoplanatism on LEO Satellite-to-Ground Laser Communications Link

Low Earth Orbit (LEO) satellite-to-ground laser communications (SGLC) link experience continuous variation in both the propagation paths and the atmospheric turbulence due to the satellite's orbital motion.This paper presents an Atmospheric Turbulence Measurement System (ATMS) capable of simultaneously monitoring multiple optical paths to characterize turbulence parameters and validate anisoplanatism effects.The system evaluates atmospheric turbulence by analyzing both scintillation in light intensity and centroid drift instellar speckle images. To enhance the accuracy of centroid positioning, a sub-pixel interpolation algorithm based on Zernike moments is proposed, further enhanced through a gray-gradient-weighted strategy.Experimental results from LEO-SGLC scenarios indicate that single-path measurements consistent with the expected statistical properties of atmospheric turbulence.However, low correlation coefficients between different measurement paths were 0.0151 and 0.1667 respectively,demonstrate significant anisoplanatism. These finding sunder score the critical role of multi-path observations in identifying minute scale optimal communication windows, thereby enhancing the stability and reliability of LEO-SGLC link.

低地球轨道（LEO）卫星对地激光通信（SGLC）链路因卫星的轨道运动，其传播路径与大气湍流均会持续变化。本文提出一种大气湍流测量系统（ATMS），可同时监测多条光路径，以表征湍流参数并验证各向异性效应（anisoplanatism effects）。该系统通过分析光强闪烁与星斑图像中的质心漂移来评估大气湍流。为提升质心定位精度，本文提出一种基于泽尼克矩的亚像素插值算法，并通过灰度梯度加权策略进一步优化。低地球轨道卫星对地激光通信场景下的实验结果表明，单路径测量结果与大气湍流的预期统计特性一致；然而，不同测量路径间的相关系数分别低至0.0151与0.1667，证实了显著的各向异性效应。这些发现凸显了多路径观测在识别微小尺度最优通信窗口中的关键作用，从而提升低地球轨道卫星对地激光通信链路的稳定性与可靠性。