基于镜频抑制零差探测的全光纤测风激光雷达系统

A Doppler Wind Lidar Based on Image-Reject Homodyne Technology

相干多普勒测风激光雷达多采用外差技术来获得大气风场在雷达径向方向上的速度大小和正负.本文基于镜频抑制技术,使用全光纤90°相位控制器研制了连续相干多普勒测风激光雷达系统.该系统通过对本振光或接收信号进行相位控制,得到正交的IQ信号,采用镜频抑制技术,探测得到径向风速的大小和正负,相对于使用外差技术的相干多普勒激光雷达系统,该系统具有信噪比更高、雷达存储能力更强、在相同的ADC采样速率下测速范围更大等特点.文中最后通过与风速计的大量对比试验,进一步对连续相干多普勒测风激光雷达系统的数据的可信性进行了验证.实验结果表明,该系统测得的风向正负与风速计完全一致,风速大小的偏差为-0.03m/s,标准差为0.63m/s,具有较高的探测精度.

At present,most of coherent Doppler lidar adopts heterodyne technique to obtain atmospheric velocity and direction in the radial direction of the radar.In this paper,a continuous all fiber Doppler wind lidar system was developed based on image-reject homodyne technology and using integrated 90°optical hybrid receiver.The IQ cross signal was got through the phase control of the local or receiving signal,and the radial wind was detected based on the image-reject homodyne technology.Compared with the lidar using heterodyne technique,this lidar presents some advantages,including higher signal to noise,stronger radar storage,greater speed range at the same ADC sample rate and so on.In the end,a lot of comparative experiments were implemented to verify the credibility of all fiber Doppler wind lidar.The results show that thissystem has high detection accuracy,the wind direction goes all the way with the anemometer,the wind speed bias is of-0.03 m/s and standard deviation is of 0.63 m/s.