地星大气湍流路径三层传输模型数值模拟  

Numerical simulation of three-layer transmission model for ground-to-satellite turbulent path

作　　者：沈玲君 宋英雄[1,2] Shen Lingjun;Song Yingxiong(Key Laboratory of Specialty Fiber Optics and Optical Access Networks,China Shanghai University,Shanghai 200072,China;Shanghai Institute for Advanced Communication and Data Science,Shanghai 200072,China)

机构地区：[1]上海大学特种光纤与光接入网重点实验室,上海200072 [2]上海市先进通信与数据科学研究院,上海200072

出　　处：《红外与激光工程》2023年第11期257-269,共13页Infrared and Laser Engineering

基　　金：国家重点研发计划项目(2021YFB2900800);上海市科委项目(22511100902,22511100502,20511102400,20ZR1420900);111计划项目(D20031)。

摘　　要：星地激光通信具有高带宽通信的潜力,但大气湍流会显著影响卫星对地和地对卫星这类通信系统的能力。星地通信系统的室外实验费用昂贵且难以重现,现有的数值仿真大都基于水平均匀路径,不适用于星地链路长距离且不均匀的湍流路径,为了评估湍流对通信系统的影响,因此开发适用于星地链路的数值仿真是非常重要的。在数值仿真中,模拟湍流的相位屏数量太多会增加系统的复杂度,通过计算传统的Kolmogorov谱下相位屏为2层、3层、6层、11层以及21层时观测面光场的互相干因子并将其与理论值比较,发现三层模型能够在保证传输准确性的同时降低系统的复杂度。在此基础上,提出了地星大气激光传输三层模型,分析了不同湍流谱模型下(Kolmogorov谱与Non-Kolmogorov谱)的高斯光束辐度轮廓变化以及接收光束相干性的变化。仿真结果表明,在相同的大气条件下,与Kolmogorov谱相比,谱指数随高度变化的Non-Kolmogorov谱对传输光束的幅度以及相干性的影响更大。Objective Satellite-ground laser communication has the potential for high-bandwidth communication,but atmospheric turbulence can significantly affect the capabilities of communication systems.Outdoor experiments of satellite-ground communication systems are expensive and difficult to reproduce.Most of the existing numerical simulations are based on horizontal uniform paths,and are not suitable for turbulence paths of nonuniform satellite-ground links.In order to evaluate the impact of turbulence on communication systems,it is very important to develop numerical simulations suitable for satellite-ground links.In numerical simulation,simulating with too many phase screens will increase the complexity of the system.Therefore,it is necessary to develop a simple and reliable numerical simulation model for ground-satellite or satellite-ground turbulence path.Methods The phase screens under the Kolmogorov spectrum and the non-Kolmogorov spectrum are simulated by Fourier inversion method,and the subharmonic compensation method is used to compensate the phase screens.By calculating the constraints of the numerical simulation,a three-layer transmission simulation model is proposed.In order to verify the model,the laser transmission under the traditional Kolmogorov turbulence spectrum model with 2,3,6,11 and 21 layers is simulated on the basis of the split-step method.Results and Discussions Simulations of phase screens under the Kolmogorov spectrum and the nonKolmogorov spectrum show that the spectral index has a great influence on the phase screen simulation(Fig.4-5).Different spectral indices have different requirements for subharmonic compensation(Fig.6).The mutual coherence factor of the optical field on the observation surface is calculated,and compared with the theoretical value(Fig.7).The mean square error was used to measure the distortion between simulation and theory for different layers of phase screens(Tab.2).It is found that the three-layer model can ensure the accuracy of transmission and reduce the complexit

关 键 词：数值模拟 大气湍流 光传播 Kolmogorov谱 Non-Kolmogorov谱 分步传播算法 

分 类 号：O431.1[机械工程—光学工程]