星载激光在冰晶粒子云层中传输与散射特性及复杂体目标探测理论建模研究

The Project will research on the transmitting and scattering characteristics of spaceborne laser through the ice-crystals cloud and It will establish the theoretical modeling of complex target detection on the space-ground path, in the same time, the exploration of the basic theories, principles and development of the key technologies on the laser transmiting through and scattering form ice-crystals cloud and complex target detection of laser radar. The main works are as followings: (1)The characteristics of laser transmitting through many kinds of random distribution and movement of ice crystals is detailly studied. (2)Considering the curvature of the earth, the characteristics laser transmitting in ice-crystals cloud with the spherical boundary of are studied, and the transport theories of the wave transmitting in the discrete random medium is developed.(3)Combined laser transmitting through the ice-crystals cloud and random rough surface scattering theories, it will research the round trip transmitting and scattering problems which are the spaceborne laser transmitting ice-crystals cloud and scattering frome target on the ground and receiving by the lidar on satellite. (4) Constructing the detected theoretical models of the complex target (car, tank and aircraft) laser from satellite to earth, it is analyed effects on the target detection such as the micro-physical characteristics of ice-crystals cloud and the physical properties of surface material of target, propagated distance and other factors. The results of the project have very important significance on Chineses aerospace, national defense, meteorological and other engineering applications, and will provide advance technical support for the fields such as satellite to satellite laser communication, laser guidance, laser radar detection, laser threat warning, laser remote sensing, meteorology monitoring and so on.

项目将开展地空路径上星载激光在冰晶粒云层中传输与散射特性及复杂体目标激光探测研究，探究激光在冰晶粒子云层中传输与散射、激光雷达目标探测所涉及到基础理论、机理和关键技术上的创新。主要工作有：(1)研究激光在多种类随机分布、随机运动冰晶粒子中传输特性。(2)考虑地球曲率，研究球形冰晶粒子云层边界中激光传输特性，拓展波在离散随机介质中的输运理论。(3)将激光在冰晶粒子云层传输和粗糙面激光散射理论结合起来，研究星载激光由冰晶粒子云层传输，经地面体目标散射后被星载激光雷达探测的激光双程传输与散射问题。(4)构建星地路径上复杂体目标(汽车、坦克和飞机)激光探测理论模型，分析冰晶粒子云层微物理特性和目标表面材料物性，传播距离等因素对目标探测的影响。项目成果将对我国航空航天、国防、气象等工程应用方面有十分重要意义，为星间激光通信、激光制导、激光雷达探测、预警、激光遥感、气象监测等领域提供预先的技术支撑。

项目开展了地空路径上星载/机载激光在云层中传输与散射特性及复杂体目标激光探测研究，详细讨论了激光在高空冰晶粒子云层和低空水云中传输与散射特性、详细分析了云层环境对目标探测和激光信号传输的影响。主要完成的工作：.(1)利用解析和蒙特卡洛、DDA、T矩阵等数值方法，研究了高空卷云或冰云中单个球、椭球、六角平板、六角棱柱和任意复杂形状簇团等冰晶粒子，及低空水云中不同液水、冰水含量球和椭球形水滴粒子的激光散射强度、消光、吸收和散射系数，详细讨论了具有一定分布状态冰晶和水云粒子对激光散射、吸收和展宽频移的影响。(2)研究平面平行模式下水云、冰云大气透过率与光学厚度、有效半径、液水含量/冰水含量、地表类型等参数的变化关系。考虑地球曲率，分析了不同激光波长入射下球形云和冰云边界层大气反射率与云微物理特性、云散射模型、观测角、相对方位角等参数的变化关系。给出球形和平行平面大气大气的标量辐射传输方程及其求解，模拟了均匀和非均匀水云、冰云和重叠云的反射率和透过率随云层大气参数、观测角等的变化情况。(3)将激光在冰晶粒子云层传输和粗糙面激光散射理论结合起来，研究星载激光经冰晶粒子云层传输特性。建立了双层云和三层云模型，计算了机载激光雷达与不同高度云层高度目标间单程/双程时，激光的直接传输和一阶散射功率随目标高度的变化情况。(4)构建星地路径上复杂体目标激光探测理论模型，讨论了云层物理特性、目标表面材料物性、传播距离等对目标探测的影响。推导了考虑云层散射时的雷达方程，计算了角反射目标的LRCS，研究了激光穿过平面平行和球形边界卷云时，目标与机载不同水平距离以及不同高度对激光回波功率的影响。模拟的空间目标的轨道运行姿态，考虑大气背景衰减，研究不同经度和纬度地基观测站激光雷达对空间复杂目标后向探测的多普勒频谱特征。项目成果将对我国地空链路间激光通信、激光制导、激光雷达探测、预警、激光遥感、气象监测等领域提供基础理论支撑。