OPTICAL SCINTILLATIONS AND FADE STATISTICS FOR A SATELLITE-COMMUNICATION SYSTEM
OPTICAL SCINTILLATIONS AND FADE STATISTICS FOR A SATELLITE-COMMUNICATION SYSTEM
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DOI：
10.1364/ao.34.007742
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发表时间：
1995-11-20
期刊：
影响因子：
1.9
通讯作者：
YU, PT
中科院分区：
文献类型：
--
作者：
ANDREWS, LC;PHILLIPS, RL;YU, PT
估计的闪烁指数，分数衰落时间，预期数量的衰落，并与传播高斯光束波的衰落时间的平均持续时间开发的上行链路和下行链路激光卫星通信信道。还提供了对卫星或地面或机载接收器处的光束光点大小的估计。基于对数正态模型的弱涨落理论适用于光束光轴附近的光强涨落，前提是天顶角不太大，一般不超过60度。然而，在任何天顶角，特别是对于上行链路信道，随着指向误差的增加而发生的倾斜增加。大的离轴偏转具有特别重要的意义，因为它们意味着小的指向误差会导致通信信道可靠性的严重退化。对于较大直径的光束，离轴偏振增加得更快，并且在某些情况下，对于偏离光束轴小于1 μ rad的指向误差，会导致径向饱和效应。
Estimates of the scintillation index, fractional fade time, expected number of fades, and mean duration of fade time associated with a propagating Gaussian-beam wave are developed for uplink and downlink laser satellite-communication channels. Estimates for the spot size of the beam at the satellite or the ground or airborne receiver are also provided. Weak-fluctuation theory based on the log-normal model is applicable for intensity fluctuations near the optical axis of the beam provided that the zenith angle is not too large, generally not exceeding 60 degrees. However, there is an increase in scintillations that occurs with increasing pointing error at any zenith angle, particularly for uplink channels. Large off-axis scintillations are of particular significance because they imply that small pointing errors can cause serious degradation in the communication-channel reliability. Off-axis scintillations increase more rapidly for larger-diameter beams and, in some cases, can lead to a radial saturation effect for pointing errors less than 1 mu rad off the optical beam axis.