基于射频边缘滤波的多普勒测风激光雷达

Doppler Wind Lidar Adopting Radio-Frequency Edge Discriminator

在相干多普勒测风激光雷达(CDWL)中引入直接探测多普勒测风激光雷达(DDWL)常用的边缘技术进行实时数据处理,此边缘技术基于射频边缘滤波器实现,无需进行激光源频繁校准和精确频率锁定。这种混合CDWL结合了DDWL和CDWL的优点,在实现相干探测的同时避免了复杂的计算。在对比实验中,混合CDWL与传统CDWL的探测结果在2 km以内的较短距离上显示出良好的一致性,但在更长的距离上测量结果有很大的不确定性。后续可以通过提高激光功率、扩大望远镜观测面积或提升其灵敏度来提升所提方法的性能。

Objective Coherent Doppler wind lidar(CDWL)requires real-time signal processing with high computational complexity,which hinders the development of portable systems with high spatiotemporal resolution and long detection ranges.Despite successful implementations in various fields,high sampling rate analog-to-digital converters(ADCs)and real-time signal processing with digital signal processing(DSP)or graphics cards pose challenges for subsequent data storage and processing.Methods We propose a Doppler shift estimation method using a real-time radio frequency(RF)discriminator in CDWL.Inspired by the direct detection Doppler wind lidar(DDWL),this method converts the returned laser signal into easily processed electrical signals through a balanced detector.Subsequently,a low-complexity frequency extraction is achieved using an RF edge discriminator.Results and Discussions In the demonstration experiment,the comparison results between the proposed CDWL and the conventional CDWL show good consistency under both weak and strong wind conditions.Specifically,under strong wind conditions,a radial wind velocity difference of less than±1 m/s is achieved within a range of 2 km,with a spatiotemporal resolution of 30 m and 0.1 s.Conclusions By combining the advantages of CDWL and the edge technology DDWL,we propose and demonstrate a real-time data processing CDWL based on an RF edge discriminator.The results of the comparative experiments verify the feasibility and effectiveness of the new method.