地空链路激光脉冲波束大气湍流传输与目标散射场量的高阶统计相关特征研究

The project will research to build models on the fields of high-order statistical correlations between the laser pulse beam scattered from target with rough surface and it propagated in atmosphere turbulence in air-groud double detected paths and make the models in many national applications. In the same time, some new technologies, novel conceptions on the target detected in atmosphere turbulence will be seeked, and some breakthroughs and innovations on the theories of laser scattering and propagation will be realized. The mainly works are as followings: (1) the high-order statistical characteristics of laser pulse beam sacttering from the target and rough surface will be obtained. (2) The characteristics of laser pulse beam propagated in the weak and strong air-ground atmosphere turbulence will be studied, to detailly discuss the level and slant path of the second order, fourth order statistical moments, and analyze the impact of atmospheric turbulence on the laser pulse beam propagation. (3)Under atmosphere turblunce en environment, the interesting researchs of high-order statistical correlations between the laser pulse beam scattered and propagated fields will be carried out to seek out the electromagnetic and optical principles which laser speckle is produced.Our resultes will build foundations for further study laser imaging evaluation and dynamic speckle detection. (4)It will establish the target laser pulse beam detection models and applied researchs in the path of the air-ground atmospheric turbulence environment, and analyze the surface material physical-optical properties of the target, atmospheric turbulence models, spread distance and other factors impact on the laser pluse beam detection effects.The results of the project will offer refined models for our national air-ground laser target detection. It is important for our national aerospace, defense, meteorological departments having a great significance.

项目将开展地空链路上激光脉冲波束大气湍流传输与目标散射的高阶统计相关特征建模和应用研究，寻求大气湍流、目标探测所涉及到的新技术，新概念，实现激光散射和传输基础理论的突破和创新。主要工作有：(1)获取粗糙面和体目标激光脉冲波束散射场的高阶统计特征。(2)研究从弱到强大气湍流激光脉冲脉冲波束的传播特征，讨论水平和斜程路径传输场量的二阶、四阶和高阶统计特征，分析大气湍流对激光脉冲波束传播的影响。(3)开展体目标激光脉冲波束散射场量和传输场量高阶统计相关性研究，寻求激光散斑产生的电磁和光学理论机理，奠定激光成像评估和动态散斑探测的研究基础。(4)建立地空链路上目标激光脉冲波束探测模型，分析目标表面材料自身物性、大气湍流模式，传播距离等因素对探测结果的影响。项目成果将为我国开展地空目标激光探测提供精细模型，对航空航天、国防、气象等部门中激光雷达探测、监测工程应用有重要意义。

本项目研究了激光脉冲波束随机粗糙面、体目标散射场的二阶、四阶和高阶统计特征。在地空路径上大气湍流环境下，研究了脉冲波束大气湍流传输场量和目标散射场量的相关统计特征。主要研究内容有四个方面：1).体目标脉冲波束散射场统计特征的研究。将脉冲和波束散射基本理论结合起来，研究随机粗糙表面脉冲波束散射场量时频域、空域的统计矩特征。数值计算了单/双站探测条件下，粗糙表面激光脉冲波束散射场量的双频互相关函数、相干和非相干散射截面，互相干函数随散射角的变化情况，分析四种不同材料，不同粗糙度等因素对粗糙表面散射场二阶特征的影响，并利用随机过程和统计光学理论，研究了目标脉冲波散射场量二、四阶统计特征建模，获取了在轨运动目标的激光多普勒成像。2).脉冲波束在大气湍流环境下的传输特征研究。研究了从弱到强大气湍流中脉冲波束传播对数振幅和相位起伏的相关函数与结构函数，推导了大气湍流传输过程中场的二阶、四阶统计矩等相关特征（如随机湍流介质中双频互相关函数、双频双点互相关函数），给出接收面处GSMP波束的平均强度，波束半径和双频复相干度的表达式，讨论了频率，初始脉冲宽度，束腰半径，天顶角和湍流外尺度对复相干度的影响。3).湍流环境下的体目标脉冲波束散射和传输场量相关特征研究。依据Huygens-Fresnel原理，考虑大气湍流对激光脉冲波束从发射机到目标和从目标到接收机双程路径的影响。建立具有相干和非相干散射分量(境反射和漫反射)随机粗糙体(如角反射器，圆球)目标激光脉冲波束探测模型。4).建立了目标激光脉冲波束大气湍流环境下的探测模型。结合大气湍流模式，分别给出球、角反射器及其阵列等典型目标的地-空路径上脉冲波束入射下大气湍流散射特征。分析材料自身物理特性如高度起伏，表面涂层介电常数，反射率，传播距离等等因素对探测效果的影响，建立了大气湍流环境下的激光“散斑”理论模型。项目的研究成果将为地空路径上的目标激光探测提供预先理论研究基础。