地面激光扫描多站点云整体定向平差模型

摘要

为一次性解算多站地面扫描点云坐标转换参数，将各站点云坐标转换成工程测量指定坐标，提出基于光束法区域网平差(BBA)的数学模型。以扫描站射向标靶中心的光束为单元建立平差方程，并将基于罗德里格矩阵的坐标转换方程作为平差的基础方程；单光束列立附有未知数的条件方程，公共标靶上相交的光束列立附有限制条件的方程。根据观测值选择的不同，可将数学模型分为6种。以假设指定坐标无误差、扫描坐标为有误差的观测值的数学模型进行多站点云定向试验，结果表明其外部符合精度达到厘米级，精度明显高于独立模型法(IMM)；扫描坐标经转换后，能满足1∶500地形图测量精度。%In order to calculate parameters of coordinate-converting of multi-stations TLS point clouds and convert point clouds in scanner’s own coordinate system to specified-engineering surveying coordinate system,a mathematical model regarding bundle block adjustment is proposed.Based on Rodrigo matrix, the model sets the l ights between the central of scanner and targets as units which make up adjustment equations.The equation is accompanied unknowns for single l ight and constraints for l ights between shared targets.There are six approaches to bundle block adjustment according to different types of observations. Our experiments showed one of them under the condition of mathematic model l ies in the assumption that specified coordinates is of high accuracy whi le scanned coordinates contains several measurement errors. The final experiments results show that the external-accordance-accuracy is within 1 cm,indicating an order of magnitude improvement when compared with independent models(IMM).Converted scanner’s own coordinates are capable of meeting the accuracy of terrestrial map surveying with the scale of 1∶500.