Improving the Spatial Accuracy of UAV Platforms Using Direct Georeferencing Methods: An Application for Steep Slopes

The spatial accuracy of unmanned aerial vehicles (UAVs) and the images they capture play a crucial role in mapping process. Researchers are exploring solutions that use image-based techniques such as structure from motion (SfM) to produce topographic maps using UAVs while accessing locations with extremely high minimal surface measurements. Advancements technology have enabled real-time kinematic (RTK) increase positional 1–3 times ground sampling distance (GSD). This paper focuses on post-processing (PPK) achieve GSD or better. To this, precise satellite orbits, clock information, UAV global navigation system observation files utilized calculate camera positions highest accuracy. RTK/PPK analysis is conducted improve accuracies obtained different flight patterns altitudes. Data collected at altitudes 80 120 meters, resulting values 1.87 cm/px 3.12 cm/px, respectively. evaluation checkpoints proposed PPK methodology one control point demonstrated root mean square error 2.3 cm (horizontal, nadiral) 2.4 (vertical, an altitude m, 1.4 oblique) 3.2 terrain-following) m. These results suggest can for image georeferencing. main contribution this evaluate approach assess effect maps.