地面激光扫描多站点云整体定向平差模型

为了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,可将数学模型分为六种。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实验,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;扫描坐标经转换后,能满足1:500地形图测量精度。

Overal l Orientation Adjustment Model of Terrestrial Laser Scanning Multi-station Point Clouds

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 lights between the central of scanner and targets as units which make up adjustment equations. The equation is accompanied unknowns for single light and constraints for lights between shared targets. There are six approaches to bundle block adjustment according to different types of observations and experiments showed one of them called "mathematic model lies in the assumption that specified coordinates is of high accuracy while scanned coordinates contains several measurement errors ". The final experiments results show that the external-accordance-accuracy is within 1CM, indicating an order of magnitude improvement when compared with Independent Models. Converted scanner's own coordinates are capable of meeting the accuracy of terrestrial map surveying with the scale of 1:500.