中国激光, 2011, 38 (10): 1005001, 网络出版: 2011-09-16
散斑噪声对相干激光雷达系统性能的影响
Impact of Speckle Noise to the Property of Coherent Lidar System
相干光学 调频连续波激光雷达 散斑噪声 拍频信号 coherence optics frequency-modulated continuous-wave lidar speckle noise beat-frequency signal
摘要
散斑噪声会影响调频连续波(FMCW)相干激光雷达的拍频信号质量,进而影响雷达的探测性能。为衡量该影响并优化系统设计,采用几何光学近似的方法对散射场进行了简化处理。通过蒙特卡罗模拟仿真建立了散斑噪声对系统拍频信号强度的影响模型,并优化了系统光学天线孔径的设计。系统测试实验结果表明,拍频信号的强度与粗糙面高度和波长的比值成负指数关系,且弱散射表面的信号强度衰减更快。实验结果与理论和仿真分析相吻合,优化设计后的系统可对存在散斑噪声的拍频信号进行有效探测,且其测距和测速误差分别小于1 cm和0.05 cm/s。
Abstract
The characteristics of beat-frequency signal (BFS) and the detection performance of the frequency-modulated continuous-wave (FMCW) coherent lidar are influenced by speckle noise. In order to estimate the impact and improve the system′s property, the scattered field is simplified utilizing geometrical optics approximation. The impact model of BFS affected by speckle field is derived by Monte Carlo simulation, and the optical antenna′s aperture is optimized. The system experiment is carried out, and the results demonstrate that the BFS intensity has a negative exponential relationship with the ratio of the surface-roughness height to the square of light wavelength, and it decreases more rapidly with weak scattering surfaces. The experimental results are in good agreement with the theoretical analysis and numerical simulation results. After system optimization, the BFS with speckle noise can be detected effectively, and the system′s range and velocity measurement errors are less than 1 cm and 0.05 cm/s, respectively.
宋凝芳, 杨德钊, 孙鸣捷, 欧攀, 林志立, 贾豫东, 江云天. 散斑噪声对相干激光雷达系统性能的影响[J]. 中国激光, 2011, 38(10): 1005001. Song Ningfang, Yang Dezhao, Sun Mingjie, Ou Pan, Lin Zhili, Jia Yudong, Jiang Yuntian. Impact of Speckle Noise to the Property of Coherent Lidar System[J]. Chinese Journal of Lasers, 2011, 38(10): 1005001.