机载激光通信链路中光场二阶特性的分析计算

为了评估大气湍流对机载激光通信系统的影响，理论分析和数值计算了机载激光通信链路中传输光场的二阶特性，包括接收光斑尺寸、光斑偏移量、光束相干半径、光束到达角起伏。计算结果表明:大气湍流对空间激光通信系统的影响主要在低空对流层，并随着机载平台高度的增加而降低。由于受到低空大折射率结构常数的影响，上行链路的接收光斑尺寸、光斑漂移量比下行链路大。下行链路光束到达角抖动比上行链路大，其值为若干rad。提出的模型及计算结果，可以为机载激光通信系统设计及性能评估提供参考。

Analysis and calculation of second-order statistics of transmitted beam in airborne laser communication system

In order to predict and estimate the effects of the atmosphere turbulence on airborne laser communication system, the second-order statistics of transmitted beam are deduced and calculated, which include beam diameter, beam wander, spatial coherence radius and the angle of arrival. The results show that the effects of atmosphere turbulence on airborne laser communication will be mitigated significantly as the altitude of airborne platform increases. Due to the larger atmosphere refractive index structure constant in lower altitude, the beam diameter and beam wander in uplink are larger than those in downlink. The angle of arrival in downlink is on the order of several rad, which is larger than that in uplink. Based on the methods and the results, the effects caused by atmosphere turbulence on airborne laser communication systems can be predicted and estimated accurately.