Use of low-cost UAV photogrammetry to analyze the accuracy of a digital elevation model in a case study

For the geodetic survey of the terrain surface, the use of conventional surveying methods and instruments is common. New technologies, such as e.g. UAVs and their combination with a digital camera, bring new opportunities also in the documentation of Earth’s surface. This combination of technologies allows for the use of low-cost digital photogrammetry to document the Earth’s surface in relation to mining activities. The aim of the research presented in this paper is to analyze the accuracy of the digital elevation model (DEM) obtained using low-cost UAV photogrammetry. The surface mine Jastrabá (Slovakia) was chosen as the test area. The mine has morphologically dissected surface and is thus suitable for verifying the use of UAV photogrammetry to capture fairly intricate details on the surface. The research, which has been carried out, showed that the model created from photogrammetric data from the UAV achieves the accuracy required by current national legislation. From the selection of the test consisting of 237 points, only 3 points failed the conditions for the accuracy of the detailed points. These results indicate that the combination of low-cost UAV and a digital camera may be used as a viable alternative for the collection of data with the goal to document surface structures and to form 3D models formed from this data. The use of UAV in a photogrammetric survey of the mine brings new opportunities for the creation of documentation, because with this technology we can measure the entire surface in detail, create orthophoto maps of the entire area and document inaccessible parts of the area such as sludge dumps, and steep slopes.