2μm星载相干测风激光雷达风速及风向误差建模与分析

Error modeling and analysis on wind speed and direction for 2μm space based coherent Doppler LIDAR

基于全微分和统计理论推导了星载相干测风激光雷达合成水平风速和风向误差的解析表达式,利用克拉默-拉奥误差下界代替Frehlich经验公式对风场的随机风速误差进行评估,建立了通用型的星载相干测风激光雷达合成水平风速和风向误差计算模型.在NASA/NOAA提出的星载测风激光雷达系统设计指标框架下,对风速及风向误差模型进行可行性分析,得到了总的径向随机误差随着探测距离的变化关系及水平风速区间的选取对随机误差的影响.同时,为了计算合成采样误差,改变不同的垂直分辨率和方向角取值,对水平分量的采样误差进行对比分析.仿真结果表明,合成的水平风速和风向的误差范围为0.8~3.2 m/s和2.38°~3.49°,基本符合星载测风激光雷达的相关指标要求.

Based on the total differential and statistical theory,the analytical expressions of the synthesis horizontal wind speed and direction error are derived. Using Cramer- Rao lower bound instead of Frehlich＇s empirical formula,the random wind errors are evaluated,and then a universal horizontal wind speed and direction error calculation modeling is established. Based on the design framework proposed by NASA / NOAA,a combination of simulation parameters is selected for the feasibility analysis of the error modeling. The Changing relation of the total radial random error and the detect range and the horizontal wind range is drawn. M eanwhile,in order to calculate the sampling error,a combination of vertical resolutions and orientation angles is chosen for comparative analysis. The results showthat by using this mode the synthesis horizontal wind speed and direction errors are in the range of 0. 8 ~ 3. 2m / s and 2. 38 ° ~ 3. 49 °respectively,basically in line with relevant requirement indicators.