空间多普勒激光雷达地面散射信号分析

Analysis on ground scattering signal of Doppler lidar in space

为了扩展空间多普勒激光雷达地面散射信号的应用范围,采用多个机载多普勒激光雷达飞行实验数据,对地面散射信号的强度、海拔高度、速度等特征进行了数据分析,并利用地面散射信号与上层大气信号强度的比值,可以等效体现地面反射率特征,即地面散射信号解算的海拔高度与数字海拔高度模型数据相吻合,两者平均值偏差小于20m,标准偏差小于100m;使用地面散射信号实现飞机速度校正,与使用飞机平台数据解算的结果具有较好的一致性,采用直接探测手段时,标准偏差小于1.5m/s,采用相干探测手段时,标准偏差小于0.5m/s,验证了利用地面散射实现空间平台速度校正的可行性。另外,针对云散射信号的存在和影响,提出了一种利用海拔高度数据比对的方法,实现云散射和地面散射的识别。

In order to expand the application of ground scattering signal for Doppler lidar in space,the characteristics of ground return in intensity,elevation and velocity are analyzed by using the flight data of several airborne Doppler lidars.The backscattering ratio of ground to the upper atmosphere can be used to reflect equivalently the ground reflectance properties,the comparison of ground elevation derived from lidar signal and digital elevation model shows a good consistency,with a mean deviation below 20 mand a standard deviation below 100m;the dopper information of ground return can also be used for the plane speed correction,and the results shows a good consistency to the platform data results,with a standard deviation below1.5m/s for direct detection system and 0.5m/s for coherent detection system.The feasibility of velocity correction using ground return is verified.Besides these,a new method for the discrimination of cloud and ground return in a way of elevation comparison is proposed and analyzed.