大气闪烁对无线激光通信效能的影响

Atmospheric scintillation effects on wireless laser communication

由于大气湍流的存在,使激光信号在大气传输中产生振幅的随机起伏,称为大气闪烁。大气闪烁将引起激光通信误码率的增加。由光强起伏大小的统计规律和通信基本原理推导出了弱湍流条件下由光强闪烁引起的误码率计算公式,分别建立了地面水平链路和地-空斜向链路中的大气闪烁误码率模型,对模型进行了仿真,分析了湍流强弱、信号调制方式、链路距离、激光波长及地面发射仰角对闪烁误码率的影响,得到了闪烁误码率的变化规律。结果表明,通过合理选择信号调制方式、激光波长、站址位置及地面发射仰角等方式能够有效地降低大气闪烁误码率,提高通信可靠性。

The bit error rate（BER） of the laser communication system is brought by the atmospheric scintillation. The BER formula of the laser communication system at weak turbulence is deduced based on the statistical characteristic of the laser intensity variance and communication theory. The BER model of the laser communication system on the earth and from earth to space are established separately. The effect of the atmospheric turbulence, modulation, channel dis- tance,laser wavelength and elevation on the BER is analysed by simulating the BER model. The changing law of the BER is discussed. It shows that the BER can be decreased by choosing appropriate modulation,laser wavelength, sta- tion position and elevation.