精灵4RTK无人机在铁路勘测中的应用与精度评价

Application and Precision Evaluation of Phantom 4 RTK in Railway Survey

因外业像控点测量往往制约着整个项目进度,所以研究免像控技术具有特别意义。经分析,低空航摄影像的外方位元素与内方位元素是影响小型无人机测图精度的2个关键因素。以大疆精灵4RTK为例,通过无人机集成的高精度POS系统,可直接获得测图所需的6个外方位元素,以实现影像高精度定位与定姿;再通过严格的相机检校获得相机精确的内方位元素参数;通过Pix4Dmapper图像处理软件,匹配处理得到数字正摄影像和数字地表模型;最后在清华山维EPS平台上构建基于三维模型的大比例地形图。在某铁路勘测过程中,使用大疆精灵4RTK免像控无人机进行重要工点测绘,其平面中误差为2.5 cm,高程点中误差为3.1 cm,精度满足规范要求。

In view of field image control point measurement often restricts the progress of the entire project,the research on photogrammetry without image control point is of special significance.By analysis,the external and internal orientation elements are two key factors that affect the accuracy of the mapping of small UAVs.Take DJI Phantom 4RTK as an example.Through the integrated high-precision POS system,6 external orientation elements could be obtained to achieve high-precision image positioning and posture;the precise internal orientation element parameters of the camera could be obtained then by applying strict camera calibration;Using pix4dmapper software and applying a matching process,DSM and DOM are obtained later.Large-scale topographic map drawing could be completed by the EPS platform.In the course of a railway survey,DJI Phantom 4RTK was adopted to survey and map important area.The error in the plane was 2.5 cm while the error in the elevation was 3.1 cm.The accuracy met the specification requirements.