连续模式相干测风激光雷达性能优化分析及实验研究

Performance Optimization and Experimental Research of Continuous Wave Coherent Wind Lidar

基于风场探测的需求,采用1 550 nm波长连续激光种子源搭建了一套全光纤结构多普勒相干测风雷达系统。从雷达方程出发,对连续激光相干雷达载噪比方程和不同雷达收发望远镜聚焦位置下风速合成权重进行了分析。针对测风雷达要求设计了5~200 m的变焦激光收发望远镜模块。扩束系统采用伽利略折射式结构,发射光束准直下扩束比为23,光学质量接近衍射极限。标定测试通过对旋转电机圆盘转速测量完成。转盘转速范围为-3 000 r/min到+3 000 r/min,转盘直径为26 cm。在视向速度多普勒频移分别为正向和负向时,雷达系统速度测量结果与通过圆盘转速计算值的相关系数为0.998与0.993,标准差为0.151 m/s和0.229 m/s。使用该测风激光雷达开展室外大气风速探测实验,取得了良好效果。

Based on the requirement of wind velocity measurement,an all-fiber doppler coherent wind lidar system is built with continuous wave laser source at band 1550 nm.It is analyzed theoretically for the Carrier-to-noise ratio function of the continuous wave coherent lidar and the weighing function of the wind velocity at different focusing distance on the basis of the lidar equation.A vari-focusing optical antenna with the focusing distance range from 5 m to 200 m is designed and fabricated according to the requirement of wind detection.The optical beam expanding module adopts the Galilean refractive structure with the beam expanding ratio as 23 and the optical quality is close to the diffraction limit.The calibration test is executed by using a rotating motor disk.The rotation speed range of the disk is from-3000 r/min to+3000 r/min.The diameter of the disk is 26 cm.While the doppler frequency shift of the line of sight velocity is positive and negative,the correlation coefficients between the velocity measurement data of the lidar system and the theoretical calculation result are 0.998 and 0.993.At the same time the standard deviations of velocity are0.151 m/s and 0.229 m/s,respectively.The wind lidar is then used to measure the atmospheric wind speed.It works correctly to apply the wind lidar to measure the atmospheric wind velocity.