机载激光雷达姿态角补偿及其效果验证

机载激光雷达(LiDAR)扫描被测地形获得激光点云,进而重建被测地形的三维图像。机载激光雷达测量过程中,机载平台姿态角时刻发生波动,其对激光点云密度分布及重建三维成像精度具有显著影响。为消除姿态角波动对激光雷达测量的不利影响,设计了一套姿态角补偿装置,包括机械结构设计和控制系统设计;并搭建了半物理仿真实验系统,编制了总控制软件使各子设备之间时间同步控制及数据采集,实现了对机载激光雷达工作原理及姿态角补偿原理的实验仿真和补偿效果验证,补偿后DSM高程精度的RMSE误差由3.50mm以上减小到3.28mm。实验结果表明,搭建的半物理仿真实验系统可正确模拟机载激光雷达的工作过程,设计的姿态角补偿样机对机载激光雷达点云产品质量有显著的补偿效果。

Effectiveness verification of attitude compensation for airborne LiDAR

Airborne LiDAR scans a terrain surface to obtain a laser point cloud, which is used to reconstruct a 3-D image of the surveyed terrain. During the measurement procedure of airborne LiDAR, the attitude angles of the airborne platform always fluctuate, which has a significant influence on the point density distribution of the laser point cloud and on the accuracy of the reconstructed digital surface model (DSM). In order to compensate for the adverse effects of attitude fluctuations, an attitude compensation prototype was designed that includes the mechanical structure and control system design. To verify the influence of attitude fluctuations on LiDAR measurements and to validate the compensation effectiveness of the designed attitude compensation prototype, a semi-physical simulation system was set up. The total control software was programmed to realize the time-synchronization control and data acquisition of all sub-systems. Using the semi-physical simulation system, the imaging procedure of airborne LiDAR and the attitude compensation principle were simulated and verified, and the RMSE of the post-compensation DSM was reduced to 3.28 mm from the original that was over 3.50 mm. Experimental results show that the working process simulation for airborne LiDAR and the compensation principle of the designed attitude compensation prototype are correct, and that the attitude compensation prototype has significant compensation effectiveness for airborne LiDAR.