LiDAR标签和栅格占有图结合的LiDAR/IMU空间标定方法  

A LiDAR/IMU spatial calibration method based on LiDAR labels and occupancy grid map

作　　者：钱闯 张红娟 李文卓[2] 刘晖 李必军[2,3] QIAN Chuang;ZHANG Hongjuan;LI Wenzhuo;LIU Hui;LI Bijun(Intelligent Transportation Systems Research Center,Wuhan University of Technology,Wuhan 430063,China;State Key Laboratory of Information Engineering in Surveying,Mapping and Remote Sensing,Wuhan University,Wuhan 430079,China;Engineering Research Center for Spatio-temporal Data Smart Acquisition and Application,Ministry of Education of China,Wuhan University,Wuhan 430079,China;GNSS Research Center,Wuhan University,Wuhan 430079,China)

机构地区：[1]武汉理工大学智能交通系统研究中心,湖北武汉430063 [2]武汉大学测绘遥感信息工程国家重点实验室,湖北武汉430079 [3]武汉大学时空数据智能获取技术与应用教育部工程研究中心,湖北武汉430079 [4]武汉大学卫星导航定位技术研究中心,湖北武汉430079

出　　处：《测绘学报》2023年第9期1469-1479,共11页Acta Geodaetica et Cartographica Sinica

基　　金：国家重点研发计划(2021YFB2501100)。

摘　　要：LiDAR和惯性测量单元(inertial measurement unit,IMU)在智能汽车获得了广泛的应用,比如高精度地图构建、车辆实时定位等。两种传感器进行组合测量时,需要知道两者之间的空间关系,包括空间旋转和平移参数。本文提出了一种基于LiDAR标签的自动化LiDAR/IMU空间标定方法。首先分析了LiDAR/IMU标定参数对LiDAR点云拼接的影响,证明了当车辆近似直线运动时,使用概略标定参数即可利用IMU的姿态信息将LiDAR点云转换到轴向近乎一致的坐标系。基于该结论,提出了一种基于IMU姿态约束的LiDAR栅格占有图构建方法,构建高相对精度的点云地图与LiDAR标签的点云进行地图匹配,获得LiDAR标签在图中的位置,相对于单点云帧互匹配方法,提高标签点云匹配的精度和可靠性。然后基于LiDAR标签的已知高精度位置,采用非线性优化方法解算栅格占有图与LiDAR标签的空间转换关系,进而求解LiDAR/IMU的空间标定参数。试验结果表明,利用本文方法获得的标定参数构建的点云地图,可实现厘米级的绝对位置精度,验证了本文方法的正确性和可行性。LiDAR and inertial measurement unit(IMU)have been widely used in intelligent vehicles,such as high-precision map generation,real-time vehicle positioning,etc.When LiDAR and IMU work together,it is necessary to know the spatial relationship between the two sensors,including the spatial rotation and translation parameters.This paper proposes an automated LiDAR/IMU spatial calibration method based on LiDAR labels.We first analyze the influence of LiDAR/IMU calibration parameters on LiDAR point cloud splicing,and prove that when the vehicle moves approximately in a straight line,LiDAR points are converted to a consistent axial direction using the approximate calibration parameters of LiDAR/IMU.Based on this conclusion,a method for generating a LiDAR grid occupancy map with high relative accuracy based on IMU attitude constraint is proposed.Point clouds of LiDAR labels with high-precision global position are matched with the map to obtain positions of the labels in the map.Based on the known high-precision position of the LiDAR labels,a nonlinear optimization method is used to solve the spatial transformation relationship between the grid occupancy map and the LiDAR labels,and the spatial calibration parameters of the LiDAR/IMU is further solved.The experimental results show that the point cloud map constructed by the solved LiDAR/IMU calibration parameters can achieve absolute position accuracy of centimeter level,which verifies the feasibility of our method.

关 键 词：空间标定 激光雷达 惯性测量单元 激光雷达标签 

分 类 号：P228[天文地球—大地测量学与测量工程]