Satellite-to-Ground Optical Communication Systems under Orbital Deviations and Atmospheric Turbulence: Channel Modeling and Performance Analysis

Satellite-to-ground optical communication (SGOC) employs lasers as carriers, providing high bandwidth, low implementation costs, and enhanced security, making it a promising technology for future satellite network deployments. However, variations in the satellite's initial relative state during operation can result in orbital deviations and atmospheric turbulence, both of which adversely affect the SGOC system's communication performance. To address these challenges, this paper examines SGOC performance under the combined effects of satellite orbital deviations and atmospheric turbulence. First, an SGOC system consisting of a single satellite and a ground receiving station is established, and the probability density function of pointing errors induced by orbital deviations is derived. Next, a channel model incorporating both atmospheric turbulence and pointing errors is proposed, and a closed-form expression for the system's average bit error rate is derived using Meijer's G-function. Finally, Monte Carlo simulations are conducted to validate the theoretical findings and uncover how key parameters related to the satellite's initial relative state influence pointing errors and SGOC system performance.