角度调谐直接探测多普勒激光雷达误差分析

Analysis of errors induced by angle tuning in direct detection Doppler wind lidar

角度调谐误差影响多普勒测风激光雷达测量精度.针对角度调谐误差,理论上推导出F-P标准具的透过光强与入射光角度以及其发散角之间的关系式.利用该式仿真计算出入射角、激光束散角、激光线宽和标准具步进角度对测风误差的影响.结果表明,在基于气溶胶散射的直接探测多普勒测风激光雷达系统中,当系统分辨率为2×106时,F-P标准具孔径至少为8 cm;在正入射附近,当激光的发散角<150μrad时,激光入射角每改变10μrad,F-P标准具透射谱中心就会移动1 MHz,即对于1 064 nm波长,测量误差为0.5 m/s.

The wind measurement accuracy was influenced by the errors of angle tuning in direct detection Doppler wind lidar. Aiming at the errors of angle tuning, theoretically, we deduced the expression between the transmission of F-P etalon and the incident angle and divergence of laser, by which the errors induced by the incident angle, divergence, line-width and stepping angle were analyzed. In the direct detection Doppler wind lidar system using aerosol scattering, simulation results show that when the system resolution is 2 × 10^6, the diameter of F-P etalon should be larger than 8 cm ; in the region of approximate normal incidence, with the divergence below 150 μrad, the peak of transmission spectrum shifts 1 MHz when the incident angle is altered for 10μrad, it means that the measured error is 0.5 m/s for a wavelength of 1064 nm.