Error Analysis of an Improved Algorithm for Calculating the Coordinates of Objects Based on Aerial Reconnaissance Data From an Unmanned Aerial Vehicle

The calculation of geographical coordinates of objects based on aerial reconnaissance data from unmanned aerial vehicles in the face of enemy electronic warfare is an urgent task, the solution of which can increase the efficiency of the use of unmanned aerial vehicles for military missions. In particular, high-quality processing of aerial reconnaissance data obtained from unmanned aerial vehicles in the absence of signals from the GNSS global positioning system through the use of advanced algorithms and methods will help to improve the accuracy and efficiency of determining the coordinates of ground objects. The article proposes an improved algorithm that allows obtaining the coordinates of objects on flat terrain with high accuracy using aerial reconnaissance materials. To do this, the operator selects four points that are visible both on reconnaissance materials and on reference images that are georeferenced. The selected points allow to calculate the geographical coordinates of any point on the aerial reconnaissance materials. The accuracy of the coordinates will be higher for objects located inside a quadrangle with vertices at the selected points. The marked key points allow for a projective transformation that displays how the pixel coordinates of an object in an UAV image are transformed into its geographic coordinates. To ensure high accuracy of coordinate calculation, key points should be selected around the object, i.e., in such a way that it is located inside a quadrangle with vertices at the key points. As a result of the simulations, the maximum error inside the quadrangle of key points is less than 2 m, and the maximum error outside is about 17 m. The average error inside the quadrangle of key points was slightly more than 0.5 m, and outside - about 1 m. After the simulations, the improved algorithm was tested in field tests. For this purpose, several terrain areas were selected, and the coordinates of the objects located on them were determined. Several wing-type UAVs flew over these areas. The data obtained during the field tests do not differ much from those obtained during the simulations.