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研制了一套人眼安全的全光纤相干多普勒激光测风雷达系统。系统采用1550 nm全光纤单频保偏激光器作为激光发射光源,激光器单脉冲能量0.2 m J,重复频率10 k Hz,脉冲半高全宽400 ns,线宽小于1 MHz。激光雷达接收望远镜和扫描器口径100 mm,采用速度方位显示(VAD)扫描模式对不同方位的视线风速进行测量,使用平衡探测器接收回波相干信号,通过1 G/s的模拟数字(AD)采集卡对相干探测信号进行采集,在现场可编程门阵列(FPGA)数字信号处理器中进行1024点快速傅里叶变换(FFT)得到不同距离门回波信号功率谱信息。对于获得的各方位视线风速,研究采用非线性最小二乘法对激光雷达测量的风速剖面矢量进行反演。激光雷达与风廓线雷达测量的风速进行了对比,两者测量的水平风速,风向和竖直风速相关系数分别为0.988,0.941和0.966。
A full-fiber coherent Doppler laser radar wind monitoring radar system has been developed. The system uses a 1550 nm all-fiber single-frequency polarization maintaining laser as the laser emission source. The laser has a single-pulse energy of 0.2 mJ, a repetition frequency of 10 k Hz, a full-width half-pulse width of 400 ns and a line width of less than 1 MHz. The Lidar telescope and scanner are 100 mm caliber and are used to measure wind speed in different azimuths with a VAD scan mode. Balanced detectors receive echo-coherent signals and pass 1 G / s Analog Digital (AD) The acquisition card collects the coherent detection signals, and carries out a 1024 point fast Fourier transform (FFT) in the field programmable gate array (FPGA) digital signal processor to obtain the power spectrum information of different distance door echo signals. For the wind speeds of all directions obtained, the nonlinear least square method was used to invert the wind speed profile vector measured by Lidar. The wind speed measured by laser radar and wind profiler was compared. The correlation coefficients between horizontal wind speed, wind direction and vertical wind speed were 0.988, 0.941 and 0.966 respectively.