基于合成孔径激光雷达相位补偿的大气湍流随机相位屏数值模拟方法

项目名称： 基于合成孔径激光雷达相位补偿的大气湍流随机相位屏数值模拟方法

项目编号： No.41275013

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 天文学、地球科学

项目作者： 李洪平

作者单位： 中国海洋大学

项目金额： 60万元

中文摘要： 激光大气传输湍流效应的存在会影响光束的强度和相干性，是制约合成孔径激光雷达高质量成像的重要因素之一。由于大气湍流存在间歇性，其统计规律与Oboukhov-Kolmogorov（O-K）湍流统计理论出现较大偏差，并且发现了大量的Non-O-K湍流。本课题拟根据大气折射率结构函数与功率谱的关系推导出大气湍流功率谱的也适用于Non-O-K湍流的普适表达式。依据其分性特征，建立随机相位屏的分形模型，开发随机中点位移算法进行模拟，对已有的谱反演法、多项式展开法和结构函数法进行了测试和改进，提高大气湍流畸变相位数值模拟的精度和速度。获取大气湍流参数与激光相干长度的关系，同时开发相位迭代补偿算法应用于机载SAL成像处理中，解决对流层大气湍流引入的相位畸变问题，成像结果通过模拟机载试验进行检验，并引入并行计算技术和Web-service技术搭建具有Web服务功能的SAL并行成像处理仿真平台，实现共享服务

中文关键词： 大气湍流；合成孔径激光雷达；相位屏；数值模拟；

英文摘要： The laser beams' intensity and coherence is mainly affected by atmospheric turbulence which lower the imaging ability of practical synthetic aperture ladar (SAL). Because of the intermittency of turbulence, O-K statistical law is not suited for all cases，there also exists lots of Non-Oboukhov-kolmogorov（N-O-K）turbulence. Hence due to the relationship between atmospheric refractive index structure function and power spectrum, a generalized expression (both suited for O-K and Non-O-K cases) of the atmospheric turbulence power spectrum will be induced first in this project, then based on fractal theory, a formalism to model the atmospheric turbulence phase screen is introduced, with which the random midpoint motion(RMM) algorithm is developed and used to simulate both the O-K and N-O-K phase screens respectively. Simulation accuracy is examined by comparing its phase structure function with the theoretical value. Other simulation methods including phase structure function method (PSFM), power spectrum method (PSM) and polynomial expansion method (PEM) are also examined and compared. Because the laser beam coherence length has inverse proportion to the atmospheric turbulence intensity which highly affects the imaging ability of SAL, the critical proportion rate for SAL imaging need to be given which is another resul

英文关键词： atmospheric turbulence；synthetic aperture lidar；phase screen；numerical simulation；