FMCW激光雷达几何结构精度模型与误差修正  

Model establishment and error correction of FMCW lidar

作　　者：缪寅宵 汪星宇[2] 朱浩 鲍晨兴 谭久彬 MIAO Yinxiao;WANG Xingyu;ZHU Hao;BAO Chenxing;TAN Jiubin(Institute of Ultra-precision Optoelectronic Instrument Engineering,Harbin Institute of Technology,Harbin 150001,China;Beijing Aerospace Institute for Metrology and Measurement Technology,Beijing 100076,China)

机构地区：[1]哈尔滨工业大学超精密光电仪器工程研究所,黑龙江哈尔滨150001 [2]北京航天计量测试技术研究所,北京100076

出　　处：《光学精密工程》2023年第9期1295-1303,共9页Optics and Precision Engineering

基　　金：国防科工局技术基础科研项目(No.JSJL2020203A001)。

摘　　要：为实现调频连续波(Frequency-modulated Continuous-wave,FMCW)激光雷达的高精度测量,针对激光雷达机械加工及装配过程中引入的几何结构误差,提出了基于激光雷达坐标测量误差的系统误差模型及误差修正方法。建立了激光雷达坐标系组,分析了空间坐标测量误差的来源。通过坐标系间的变换矩阵,实现了测量坐标的几何误差传递。然后,归并各坐标系的几何误差,建立了显式的激光雷达几何空间坐标误差表达式。并以此为基础,建立最小二乘优化目标,解算各项误差因子和修正后坐标。求得的误差因子可以用作后续坐标测量结果的修正。最后,基于该方法设计了一套以激光跟踪仪为高精度测量仪器、以靶球球心位置为标准点的标定场,使用激光跟踪仪与激光雷达测量相同位置的靶球完成系统误差修正。实验结果表明,经修正激光雷达空间距离测量的平均误差由0.0448%下降到0.0038%,误差极大值由4.17 mm下降到0.30 mm,验证了激光雷达几何结构误差标定和误差修正方法的有效性。The geometry of frequency-modulated continuous-wave lidar deviates from that of the design model owing to the mechanical machining and assembly of the lidar.In this study,the effect of the sub-coordinate system offset and roll on the coordinate measurement accuracy of the instrument is investigated,and a correction model is developed for the geometric error of the lidar.This model can increase the measurement accuracy of the measurement system without changing the hardware structure of the system.First,a set of lidar coordinate systems is established,and the sources of spatial coordinate measurement errors are analyzed.The geometric error transfer of the measurement coordinates is achieved by applying the transformation matrix between the coordinate systems.Then,the geometric errors of the different coordinate systems are combined,and an explicit expression for the geometric spatial coordinate error of the lidar is established.Based on this,a least-squares optimization objective is established for obtaining the error factors and the corrected coordinates.The obtained error factors can be used as corrections for subsequent coordinate measurements.Finally,this method is used to design a calibration field with a laser tracker as the high-precision measurement instrument and the spherical center of the target sphere as the standard point.A system error correction experiment is performed by employing the laser tracker and lidar to evaluate the target sphere at the same position.The experimental results indicate that the average error of the lidar spatial distance measurement is reduced from 0.0448%to 0.0038%and the maximum error value is reduced from 4.17 to 0.30 mm after the correction,thereby confirming the effectiveness of the lidar geometric error calibration and error correction method.

关 键 词：激光雷达 几何结构误差 最小二乘法 误差修正 

分 类 号：TN958.98[电子电信—信号与信息处理] TB921[电子电信—信息与通信工程]