Abstract: The shipborne mobile LiDAR 3D surveying system is a multi-sensor integrated system integrating laser scanner, global positioning system and inertial navigation system. It has the characteristics of high efficiency, high precision and 3D surveying, and it can solve the problem that traditional methods are difficult in the mapping of docks, river courses and islands and reefs. The high-precision space-time synchronization of the LiDAR surveying system is the guarantee of data fusion and high-precision 3D surveying. The placement angle deviation calibration is an important step in the surveying of system. This paper first analyzes the conversion relationship in the relevant coordinate systems in the shipborne mobile LiDAR 3D surveying system, and proposes a method to eliminate deviation based on the bridge as the calibration field. Based on the high-precision space-time synchronization, the method calculates the placement angle deviation of the roll angle, the pitch angle and the heading angle respectively by the offset of the bridge in the scanning line. Finally the reference points are used to verify the surveying accuracy after calibration. The experiment verifies the accuracy of the method and it can significantly improve the quality and accuracy of shipborne mobile LiDAR surveying data.

Key words: placement angle deviation, calibration, space-time synchronization, shipborne mobile LiDAR, surveying system