中国激光, 2014, 41 (6): 0605002, 网络出版: 2014-04-16
高空湍流影响下紫外光多径散射链路模型
Ultraviolet Multipath Scattering Link Model under the Influence of High Altitude Turbulence
大气光学 紫外光通信 大气湍流 Rayleigh散射 对数正态分布 atmospheric optics ultraviolet communication atmosphere turbulence Rayleigh scattering logarithm-normal distribution
摘要
考虑散射链路所在高空大气中温度、压强、臭氧浓度和湍流垂直强度的分布规律,依据Rayleigh散射理论,提出紫外光多径散射链路模型。将散射体划分为多个散射元,各散射元对应一组路径,并依照不同路径划分信号光,计算其信号强度;利用对数正态分布和非直视链路的湍流模型,分别计算不同路径的信号强度概率密度分布;用所有概率密度函数卷积得到接收端各路径信号叠加的强度分布和链路损耗。根据实际大气环境仿真得到:新模型得到的信号强度概率密度分布较原模型更集中,紫外光的消光系数受吸收系数影响显著,二者垂直分布曲线只在15 km以下略有差异。在高空2~14 km范围内,当收发端位于11 km左右闪烁指数存在极大值,而收发端位于6 km左右闪烁指数最小。综合考虑湍流效应和链路损耗,高空紫外光通信可将收发端安置于10 km高度以下。
Abstract
Considering the air pressure, temperature, ozone concentration and turbulence vertical distribution of scattering communication link in the upper-air, a ultraviolet multipath scattering ling model is modified, combined with Rayleigh scattering theory. The scattering volume is divorced into scattering elements and each element corresponds to every path. Signal strengths of each beams of laser divorced according to different paths are computed respectively. The probability density districutions of each non-line-of-sight signal strengths are calculated by logarithm-normal distribution and non-line-of-sight link turbulence model. Finally, total signal strength probability densities of each path signal in receiving terminal and the link losses are got by the way of each probability density convolutions. According to the factual atmosphere environment, the results show that the newly built probability density distribution is more concentrated. The differential distinction between extinction coefficient and absorption coefficient vertical distribution functions lies 15 km, due to the great impact of ozone absorption. At the range from 2 km to 14 km in the upper-air, scintillation index is higher with transmitter and receiver at the height of 11 km, while it is the lowest with transmitter and receiver at the height of 6 km. Considering turbulence and path loss, transmitter and receiver can be set below 10 km in the upper-air when ultraviolet communication is used in high atmosphere.
强若馨, 赵尚弘, 王翔, 刘韵. 高空湍流影响下紫外光多径散射链路模型[J]. 中国激光, 2014, 41(6): 0605002. Qiang Ruoxin, Zhao Shanghong, Wang Xiang, Liu Yun. Ultraviolet Multipath Scattering Link Model under the Influence of High Altitude Turbulence[J]. Chinese Journal of Lasers, 2014, 41(6): 0605002.