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依据折射率结构常数垂直分布特征,利用对数正态分布模型计算了湍流强度、高空位置、通信距离、仰角和波长影响下,紫外光非直视链路的信号强度概率密度分布和闪烁指数。结果表明:高度5km以下,闪烁指数随着收发端所在高度增加而显著下降,2km以上的高空闪烁指数已小于10-2;随着波长增大,闪烁指数减小,信号强度分布更加集中。因此,在高空2km以上的环境中,较小的闪烁指数可以令紫外光在高空通信方面取得较好的性能。同时,可采用“日盲区”波长较长的信号来减小闪烁效应。此外,采取降低仰角的方法可以降低闪烁指数或者延长通信距离。
According to the vertical distribution of structural constants of refractive index, the probability density distribution and scintillation index of signal intensity of ultraviolet indirect link were calculated by logarithm normal distribution model under the influence of turbulence intensity, altitude position, communication distance, elevation angle and wavelength. The results show that the flicker index drops significantly with the height of the sender and receiver below 5km, the flicker index above 2km is less than 10-2, and the flicker index decreases as the wavelength increases, and the signal intensity distribution is more concentrated. Therefore, a small flicker index can achieve better performance of the ultraviolet light in the altitude communication when the altitude is more than 2km. At the same time, you can use “blind zone ” longer wavelength signal to reduce the flicker effect. In addition, the method of lowering the elevation angle can reduce the flicker index or extend the communication distance.