In order to effectively suppress the strong turbulence effect caused by the wake of helicopter during landing, diversity reception technology was used for suppression. According to the characteristics of wireless ultraviolet slant communication and approximate-line-of-sight (ALOS) communication, the probability density function of edge distribution of the received signal strength was given. The correction model of UV ALOS communication system based on gamma-gamma distribution was established. The diversity reception technology was introduced into the model. The influence of turbulence effect on the edge probability density distribution of optical signal intensity was analyzed theoretically. Bit error performances of maximal ratio combining (MRC), equal gain combining (EGC) and selective combining (SC) were analyzed. The results show that, the stronger the turbulence intensity is, the worse the bit error rate performance of UV ALOS system is. With two diversities, the signal-to-noise rates of MRC, EGC and SC have increased 22 dB, 18 dB and 16 dB respectively. The diversity reception technology can effectively suppress the strong turbulence effect in helicopter assisted landing and improve the stability and anti-fading performance of communication system.%为了有效抑制直升机降落过程中尾流造成的强湍流效应, 采用分集接收技术来进行抑制.根据无线紫外光斜程通信和近直视通信的特性, 给出接收信号强度的边缘分布概率密度函数, 建立了基于gamma-gamma分布的紫外光近直视通信系统修正模型, 将分集接收技术引入该模型.理论分析了湍流效应对接收光信号强度边缘概率密度分布的影响以及最大比合并 (MRC) 、等增益合并 (EGC) 和选择性合并 (SC) 的误码性能.结果表明, 大气湍流强度越强, 紫外光近直视通信系统的误比特率性能越差;二分集时, MRC, EGC, SC 3种合并方式信噪比性能分别提升了22dB, 18dB, 16dB.分集接收技术能有效抑制直升机助降过程中的强湍流效应, 提升通信系统的稳定性和抗衰落性能.
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