一种新型三维激光扫描隧道测量点云坐标定位方法的精度评估

提出了一种基于三维激光扫描仪特殊定位硬件装置和七参数坐标转换算法，对每个扫描测站点云利用最近的隧道控制点进行绝对定位，将多个隧道扫描测站数据不经过拼接就统一转换成隧道控制测量坐标系坐标的方法——点云绝对定位法，并应用误差传播理论和相应数值模拟计算对该方法的测量成果进行精度评估和重要误差来源分析。最后得出在一定条件下采用该方法获得的隧道扫描测量成果可以满足城市地铁测量规范对竣工测量精度要求的结论。

Accuracy Evaluation for a New Positioning Method of Point Cloud Acquired by 3D Tunnel Scanning Technology

A new method based on a special accessory made for 3D laser scanner and 7-parameter coordinate transformation algorithm is introduced to directly locate every 3D tunnel scan station with the closest tunnel control point and transform the point cloud from the relative scanner coordinate system into the uniformed tunnel control coordinate system without registration of multiple scans,which is called "APM" method(absolute positioning method).Error propagation analysis and corresponding numerical calculation are also used to evaluate the accuracy of APM results and the key error source.In the end,the tunnel scan results acquired with the APM method under certain preconditions are proved to meet the accuracy requirements of tunnel as-built survey based on the Code of Urban Rail Transit Engineering Surveying.