Impact of Lidar System Calibration on the Relative and Absolute Accuracy of Derived Point Cloud

LiDAR is a rapid and effective system to collect 3D surface data. In order to achieve the expected accuracy of LiDAR data, systematic errors in a LiDAR system should be defined and removed by a calibration procedure. In this paper, we consider mounting errors (lever-arm and boresight angles) and systematic errors of a laser scanner (scan mirror angle scale and laser range bias). Those systematic errors cause not only the deterioration of absolute accuracy of point cloud w.r.t. the mapping frame but also discrepancies between overlapping strips. This paper investigates the impact of systematic errors on the positional accuracy of a LiDAR point cloud, and proposes two alternative methods for LiDAR system calibration. The first procedure, denoted as “Simplified method”, makes use of the LiDAR point cloud from parallel LiDAR strips acquired by a steady platform (e.g., fixed wing aircraft) over an area with moderately varying elevation. The second procedure, denoted as “Quasi-rigorous method”, can deal with non-parallel strips, but requires time-tagged LiDAR point cloud and navigation data (trajectory position only) acquired by a steady platform. The performance of the proposed methods is verified by evaluating the relative and absolute accuracy of the point cloud. The relative accuracy is evaluated through the compatibility comparison for overlapping strips before and after the calibration procedure. The absolute accuracy of the point cloud is evaluated by using the LiDAR data for photogrammetric georeferencing before and after performing the proposed calibration procedures.