Scintillation index is examined for annular optical beams in a strong atmospheric medium of a slant path. On-axis scintillations have small- and large-scale components and are formulated for the uplink/downlink of aerial vehicle-satellite laser communications. For this purpose, the unified Rytov method and the amplitude spatial filtering of the atmospheric spectrum are utilized. Performances given by the average bit error rate (BER) are investigated by employing the corresponding scintillation index, which is found by using intensity having gamma-gamma distribution. Strong atmospheric turbulence effects on the scintillation index and BER of the collimated annular optical beam having various thicknesses are reported for the up/down vertical links, and these are compared with the scintillations of the collimated Gaussian optical beams against propagation length, source size, and the zenith angle with the selected thickness. Utilizing the scintillations found, BER changes against average signal-to-noise ratio (SNR)are plotted for up/down vertical links. The scintillation index and BER in the downlink are found to be different than the scintillation index and BER in the uplink for strong atmospheric turbulence, mainly because the structure constant is a function of the altitude. Considering the location where the aerial vehicle and satellite are deployed as the reference points, annular beams are more advantageous than the Gaussian beams at up/down slant link lengths. The effect of the thickness of the annular beam is apparent for the uplink, where thin annular beams are more advantageous at small link lengths and thick annular beams are more advantageous at large link lengths. In the downlink, thin annular beams are more advantageous at all link lengths.

中文翻译：

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强湍流环境下使用环形光束的飞行器和卫星双向激光通信中的闪烁和误码率

在倾斜路径的强大气介质中检查环形光束的闪烁指数。同轴闪烁具有小型和大型组件，专为飞行器-卫星激光通信的上行链路/下行链路而设计。为此，使用了统一的 Rytov 方法和大气频谱的幅度空间滤波。通过使用相应的闪烁指数来研究平均误码率 (BER) 给出的性能，闪烁指数是通过使用具有伽马-伽马分布的强度发现的。对于上/下垂直链路，报告了强烈的大气湍流对具有各种厚度的准直环形光束的闪烁指数和误码率的影响，并将这些与准直高斯光束的闪烁与传播长度、光源尺寸和选定厚度的天顶角进行比较。利用发现的闪烁，针对上行/下行垂直链路绘制了 BER 相对于平均信噪比 (SNR) 的变化。发现下行链路中的闪烁指数和 BER 与上行链路中的闪烁指数和 BER 对于强大气湍流不同，主要是因为结构常数是高度的函数。考虑到飞行器和卫星部署的位置作为参考点，环形波束在上/下倾斜链路长度上比高斯波束更具优势。环形梁的厚度对上行链路的影响很明显，其中细环形梁在小连杆长度时更有利，而厚环形梁在大连杆长度时更有利。在下行链路中，薄环形梁在所有链路长度上都更有利。