角度调谐的多普勒激光雷达硬目标转速测量

利用角度调谐方法确定直接探测多普勒测风激光雷达的初始工作点,角度调节精度可达10 μrad.在此工作点处使用频率稳定性为10-7,单纵模出现概率大于98%的Nd:YAG激光器,通过偏振分光光路测得参考信号与回波信号.配合目标准确放置到准直镜的焦距上,分别测量了配合目标静止,正转和反转时的参考信号与回波信号.利用配合目标静止时测得参考信号与回波信号的关系可得参考信号的角度矫正因子为1.1949,使用该矫正因子测得硬目标在正转和反转时转速与真实转速之间的误差小于0.5 m/s.

Velocity Measurement of Hard Target in Angle-Tuned Doppler Wind Lidar

The initial operating position was set by means of tuning Fabry-Pérot etalon angle, and the accuracy of angle tuning was 10 μrad. At this position the reference signal and echo signal were measured with monostatic polarization light splitting. The longitudinal-mode Nd∶YAG laser with wavelength of 1.064 μm was used with the probability of single longitudinal mode greater than 98%, and long-time stability of laser frequency about 10-7. The hard target was placed at the focal spot of the collimating mirror. The reference and echo signal were separately measured when the hard target was still, in positive rotation and negative rotation. The correction factor about the angle of reference signal is obtained as 1.1949, by the relation between reference and echo signal when the hard target is still. The measured results indicate the velocity error is less than 0.5 m/s between measured value and true value with this correction factor.