机载LIDAR点云定位误差分析

Positioning errors analysis on airborne LIDAR point clouds

在机载LIDAR点云定位方程的基础上建立其定位误差方程,依据定位误差方程,将点云的误差分类为系统误差、任务误差和随机误差3类。详细分析了平地、下坡面、上坡面3种情形下地形坡度和扫描角对测距误差和点云定位误差的影响大小,探讨了扫描角误差、安置角误差、姿态角误差以及扫描角对点云定位误差的影响。除了分析系统误差外,还着重分析了时间偏差、GPS定位误差、偏心分量误差以及随机误差对点云定位误差的影响大小。研究发现:航高和扫描角是点云定位误差的重要误差源,下坡面地形和瞬时扫描角误差对点云定位误差的影响较大,安置角误差可以通过检校来消除,姿态角误差取决于IMU自身的硬件精度。

A positioning errors equation of airborne LIDAR point clouds was founded based on its positioning equation. Errors of point clouds were classified into three categories-systematic errors, mission errors and random errors-according to LIDAR positioning equation. The influences of slope and scanning angle for positioning errors of point clouds were analyzed in detail under planar surface, down-sloping surface and up-sloping surface conditions. The influences of scanning angle errors, mounting errors, attitude errors as well as scanning angle for positioning errors of point clouds were discussed. Except of analyzing systematic errors, influences of time deviations, GPS positioning errors, lever-arms errors and random errors for positioning errors of point clouds were also emphasized and analyzed. The results of research showed that flight height and scanning angle were crucial error sources, down-sloping surface and scanning angle errors in all error sources had great impacts on positioning errors of point clouds, mounting errors could be eliminated by calibration method, attitude errors were only rely on IMU＇s accuracy alone.