为实现近距离风场的精确实时观测, 基于连续相干探测技术, 选取人眼安全的1.55 μm为工作波长, 设计了一台激光风速仪。系统光路采用全光纤结构增强运行稳定性, 望远镜采用同轴透射式结构, 有效口径为70 mm, 测量光束聚焦距离为80 m。利用A/D采集卡上板载现场可编程门阵列芯片处理大气回波信号, 并设计了谱质心算法估计径向风速, 提高了系统运行的精确性和实时性。长期径向风速测量结果表明, 所设计激光风速仪输出信号稳定, 时间分辨率为1 s, 风速测量范围下限约为0.915 m/s。与一台校准过的脉冲相干测风激光雷达进行对比实验, 两设备测得风速数据相关系数为0.997, 标准差为0.090 m/s, 最大相差0.480 m/s。

In order to implement measurement of the close wind field accurate and real-time, a laser anemometer based on CW coherence detection was designed with eye-safe band 1.55 μm. The system optical path employed the all-fiber structure to enhance the operational stability. The telescope adopted a coaxial transmission structure with effective aperture of 70 mm and focusing distance of 80 m. The backscattered signals were processed by using the on-board programmable gate array chip on the A/D capture card and spectral centroid algorithm was also designed for wind velocity estimation. The anemometer realized high real-time and reliability. The long-term radial wind speed measurement results proved that the laser anemometer output signal was stable with a time resolution of 1 s and the lower limit of the wind measurement range was about 0.915 m/s. Compared with a calibrated pulsed coherent wind lidar, the correlation coefficient of wind speed data measured by the two devices was 0.997, the standard deviation was 0.090 m/s, and the maximum difference was 0.480 m/s.