Acta Geodaetica et Cartographica Sinica ›› 2023, Vol. 52 ›› Issue (9): 1469-1479.doi: 10.11947/j.AGCS.2023.20220242

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

QIAN Chuang1, ZHANG Hongjuan2,3, LI Wenzhuo2, LIU Hui4, LI Bijun2,3   

  1. 1. Intelligent Transportation Systems Research Center, Wuhan University of Technology, Wuhan 430063, China;
    2. State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China;
    3. Engineering Research Center for Spatio-temporal Data Smart Acquisition and Application, Ministry of Education of China, Wuhan University, Wuhan 430079, China;
    4. GNSS Research Center, Wuhan University, Wuhan 430079, China
  • Received:2022-04-07 Revised:2023-02-14 Published:2023-10-12
  • Supported by:
    The National Key Research and Development Program of China (No. 2021YFB2501100)

Abstract: 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.

Key words: spatial calibration, LiDAR, inertial measurement unit, LiDAR labels

CLC Number: