车载直接探测多普勒测风激光雷达光学鉴频器

基于建立的车载直接探测激光雷达系统,对接收光学鉴频器进行了研究。针对边界层、对流层和平流层不同的气溶胶和大气分子浓度以及风速动态范围,同时采用直接探测的两种主要技术。利用多光束菲索(Fizeau)干涉仪(MFI)和阵列光电倍增管(PMT),接收气溶胶散射信号,获得边界层风速。采用双法布里-珀罗(Fabry-Perot)干涉仪(DFP)和光电倍增管探测器,分析分子散射信号,得到对流层风场。使用实际的激光雷达系统参数和大气模型参数,对两个鉴频器进行了优化设计,分析了它们的风速测量灵敏度和精度。多光束菲索干涉仪鉴频器系统在±50 m/s风速范围内测量灵敏度为1.3%/(m.s-1),高度分辨率为200 m,边界层内风速测量误差小于1 m/s。双法布里-珀罗干涉仪鉴频器系统在±100 m/s风速范围内的测量灵敏度约为0.3%/(m.s-1),高度分辨率为1000 m,对流层风速测量误差小于3 m/s。

Optical Frequency Discriminator of a Mobile Direct-Detection Doppler Wind Lidar

The optical frequency discriminators are studied based on developing mobile direct detection Doppler wind lidar. According to the differences of aerosols and molecules densities and wind dynamic range in the planetary boundary layer (PBL), troposphere and stratosphere, the two direct-detection techniques to measuring wind speed simultaneously are proposed. The wind profile in PBL is measured by multi-beam Fizeau interferometer (MFI) combined with imaging photomultiplier tube (PMT) arrays from aerosol backscattering signals. The wind profile above PBL is sounded by double Fabry-Perot (F-P) interferometer and two PMT from molecular backscattering signals. The parameters of proposed lidar system and model atmosphere are employed to optimize the two spectrum analyzers, then the wind measurement sensitivities and the error profiles are discussed. For MFI analyzer within wind range of 50 m/s, the wind measurement sensitivity of 1.3%/(m·s-1) and the speed accuracy less than 1 m/s are got with altitude resolution of 200 m. Meanwhile, for double F-P (DFP) analyzer within wind velocity range of 100 m/s, the wind measurement sensitivity is about 0.3%/(m·s-1) and the accuracy is less than 3 m/s with resolution of 1000 m. The numerical simulation shows that Doppler lidar with the optical frequency discriminators has high sensitivity and accuracy for wind profile measurement in both troposphere and stratosphere.