Investigation Of Position Accuracy İn Uavs;

Abstract

Digital Terrain Models (DTMs) are used as primary data in many engineering projects. In addition to classical terrestrial techniques, space and satellite techniques and Unmanned Aerial Vehicles (UAVs) are commonly used in the production of the DTMs. In the production of the DTM with the help of the UAVs, measurements can be made easily where people can access hardly, and large areas can be mapped quickly. However, one of the most fundamental problems in the UAVs is to obtain the most accurate DTM by choosing the homogeneously spread ground control points (GCPs) number. In this study, the effect of flight altitude and the density of GCPs on position accuracy were investigated in production of the DTM. For this purpose, 56 points were established at approximately 40 m intervals and images from 80, 100, 120 m flight altitude were taken in the test area. The rapid static Global Navigation Satellite Systems (GNSS) method was used to obtain the coordinates of the points with high accuracy. Then, the homogeneously spread 5, 10, and 15 points were chosen as GCPs, respectively. The images were evaluated in Pix4d Mapper software with 9 different combinations and DTMs were produced. Outliers of the coordinates obtained from the models were detected by Bland-Altman Plot. To determine the geometric accuracy of the produced models, the coordinates of the test points obtained from the models and the results of rapid static GNSS measurements were compared with the statistical methods and the obtained results were interpreted. © Author(s) 2023.