高空大气湍流影响下紫外光非直视链路闪烁效应研究

Influence of High Atmosphere Turbulence on Scintillation in Non line of sight Ultraviolet Channel

摘要:

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。

Abstract:

Based on vertical distribution of the structure constant of refractive index, the strength distribution of optical signal and scintillation index of ultraviolet non line of sight link were calculated by analyzing the effects of turbulence strength, height, communication distance, emitter elevation and wavelength with Log normal distribution model. The simulation results show that, the scintillation index decreases remarkably with the height increasing below 5km, which is below 10-2 when the height is higher than 2km. With the increasing of wavelength, the scintillation index decreases. Hence, considering the small scintillation index at the height above 2km, ultraviolet communication system can realize good performance at higher atmosphere. And choosing lower elevation and longer wavelength can effectively lower the scintillation index and also extend the communication distance.