基于激光器输出模式的离轴激光雷达重叠因子计算及近场信号校正

基于几何分析，将离轴激光雷达在近距离范围内望远镜视场与发射激光分布的交叠区分为三种形状，并给出了计算离轴激光雷达重叠因子的解析计算公式.基于该公式和发射激光的高斯分布得到了本实验室Mie散射激光雷达重叠因子随高度的变化曲线.利用该曲线对成都地区在不同天气状况下的雷达回波信号进行了校正.在此基础上，利用Klett算法对校正后的回波信号进行了反演，得到了532 nm波长大气消光系数随高度的变化曲线.结果表明，基于文中校正方法得到的大气消光系数能反映实际的天气情况. 关键词： 离轴雷达 重叠因子 高斯模式

Calculation of the overlap factor and correction of near-field signal of the off-axis lidar based on the Gaussian mode of laser beam

Based on the geometrical analysis, the near-field overlapping area shape of an off-axis laser lidar, which is formed by the telescope field of view and the laser distribution, is divided into three types, and the analytical formula for calculating the overlapping factor of off-axis lidar is given. According to the formula and the Gaussian distribution of the laser mode, the curve of the overlapping factor with the altitude of the Mie scattering lidar in our Laboratory is obtained. Using the curve, the lidar return signal under different weather conditions in Chengdu is corrected, based on which the return signal is retrieved by the Klett inversion method, and the curves of the atmospheric extinction coefficient varying with the altitude are obtained. The results show that the atmospheric extinction coefficient obtained by the correction method in the study is accordant with the practical weather condition.