ABSTRACT
Monitoring structures requires a series of activities to check their technical condition, including geometry. Geodetic measurements are the basic tool here. Technological advances have made it possible to perform very detailed measurements using dense point clouds. One example is the use of low-altitude photogrammetry with unmanned aerial vehicles (UAVs). A huge advantage is the remote mapping of large areas without compromising safety in hazardous and often inaccessible areas. The results of UAV measurements provide a basis for verifying the condition of structures and ultimately constitute a source of data necessary to determine corrective measures. The study shows an example of measurements using UAVs, including in the area of a road embankment affected by underground mining. In the cases discussed, the geometry of the structures was analyzed in the context of the slopes necessary for proper water drainage. The observations carried out revealed changes such as: a significant reduction in the slope of the culvert under the road embankment from 1.9% to 0.07%. Alignment with the national coordinate system was achieved using ground control points. The georeferencing accuracies were up to 0.86 cm for XY (RMSE XY) and up to 0.53 cm for Z (RMSE Z).
