<p>Simulation parameters.</p>

Optical links supported by an unmanned aerial vehicle (UAV) must sustain gigabit-class throughput despite atmospheric attenuation, turbulence, and platform-induced pointing errors. Single-technology designs based on free-space optical (FSO) or visible light communication (VLC) often lack robustness under changing altitude and weather conditions. This paper proposes a hybrid FSO/VLC UAV relay and a unified analytical model that combines Beer–Lambert path loss, turbulence-induced scintillation, and pointing jitter, coupling an FSO backhaul to a Lambertian V1LC access channel with a finite receiver field of view (FOV). MATLAB-based results show that, under light desert dust (extinction ), the FSO branch retains of the transmitted power at 1 km and at 2 km, compared to and in clear visibility () and and in haze (). The VLC branch maintains a signal-to-noise ratio (SNR) of at least 30 dB when for altitudes below 150 m. For line-of-sight stability, with a receiver capture half-angle of , the alignment probability is at a root-mean-square (RMS) pointing jitter of (stabilized) versus at (weak/no-stabilization control). These results provide practical thresholds for robust hybrid relays, including visibility-aware switching between FSO and VLC and sub- stabilization to maintain high alignment probability for smart-city and emergency scenarios.

无人机（UAV）所支持的光链路，即便面临大气衰减、湍流效应以及平台诱导的指向误差，仍需维持吉比特级吞吐量。基于自由空间光通信（FSO）或可见光通信（VLC）的单一技术设计方案，在海拔与气象条件变化时往往鲁棒性不足。本文提出一种混合FSO/VLC无人机中继系统，以及一套统一分析模型，该模型结合了比尔-朗伯（Beer–Lambert）路径损耗、湍流诱导闪烁与指向抖动特性，将FSO回传链路与具备有限接收视场（FOV）的朗伯型V1LC接入信道进行耦合。基于MATLAB的仿真结果表明：在轻度沙漠沙尘消光条件（[原文缺失参数]）下，FSO支路在1km距离处保留发射功率的[原文缺失值]，2km距离处保留[原文缺失值]；而在晴朗能见度（[原文缺失能见度参数]）下对应值为[原文缺失值]与[原文缺失值]，雾霾天气下则为[原文缺失值]与[原文缺失值]。当[原文缺失阈值条件]时，VLC支路在海拔150m以下可维持至少30dB的信噪比（SNR）。针对视距稳定性场景，当接收捕获半角为[原文缺失角度参数]时，均方根（RMS）指向抖动为[原文缺失抖动值]（稳定控制）时对准概率为[原文缺失概率值]，而在[原文缺失抖动值]（弱/无稳定控制）下对准概率仅为[原文缺失概率值]。上述结果为鲁棒性混合中继系统提供了实用阈值，包括FSO与VLC之间的能见度感知切换，以及面向智慧城市与应急场景的亚级稳定控制方案，以维持高对准概率。