相干测风激光雷达回波相干性分析  

Coherence Analysis of Echoes From Coherent Wind Lidar

作　　者：徐荷 孙迪峰 李健兵 Xu He;Sun Difeng;Li Jianbing(State Key Laboratory of Complex Electromagnetic Environmental Effects on Electronics and Information System,College of Electronic Science and Technology,National University of Defense Technology,Changsha 410073,Hunan,China;Northwest Institute of Nuclear Technology,Xi’an 710024,Shaanxi,China)

机构地区：[1]国防科技大学电子科学学院CEMEE国家重点实验室,湖南长沙410073 [2]西北核技术研究所,陕西西安710024

出　　处：《激光与光电子学进展》2023年第14期321-329,共9页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(61771479);湖南省研究生科研创新项目(OL20210002)。

摘　　要：为探索可靠的激光雷达回波处理方式及研究大气对回波相位的影响,进行了激光雷达回波相干性分析。首先通过建立激光雷达时域模型及搭建实验系统获取仿真和实验大气回波。为排除系统误差的干扰对实验回波提取相位并脉间对齐,再基于归一化协方差函数计算仿真回波和对齐后实验回波的相关系数,发现回波脉间不相干。在证明出射脉冲的高相干性的基础上,硬目标回波的脉间积累可以实现本征频率的增强,而对齐后的风场回波脉间积累的效果远差于非相干平均,表明硬目标的漫反射能保留本征信号的相干性,而风场这类软目标严重破坏回波的相干性。Herein,the lidar echo coherence was examined to investigate a reliable lidar echo processing technique and research the impact of the atmosphere on the echo phase.By creating an experimental system and developing a time domain model of the lidar,the experimental and simulated atmospheric echoes were first obtained.Moreover,the phase of the experimental echo was retrieved and aligned between pulses to remove system-error interference.Then,the correlation coefficients of the simulated echo and aligned experimental echo were evaluated based on the normalized covariance function;it is discovered that the echo pulses are incoherent.According to the evidence of the high eigencoherence of the outgoing pulse,the interpulse accumulation of the hard target echo can increase the eigenfrequency;whereas,the effect of accumulating the aligned wind field echoes among pulses is significantly worse than the incoherent average,demonstrating that the diffuse reflection of the hard target can maintain the eigensignal coherence,while the coherence of the soft target echo,such as the wind field,is seriously destroyed.

关 键 词：测风激光雷达 数字信号处理 相干积累 非相干平均 软目标 硬目标 

分 类 号：TN958.98[电子电信—信号与信息处理]