Accuracy Analysis of Real-Time Kinematic Drones as a Replacement for GPS Bases in River Surveying

Global climate anomalies have extensively affected rivers and reservoirs, increasing the importance of accurate river surveying for effective river construction and management. While conventional leveling methods are commonly used for river surveying, GPS technology with Global Navigation Satellite System (GNSS) receivers is also performed. In addition to GPS, unmanned aerial vehicle (UAV)-based aerial photogrammetry has recently been adopted for surveying. Precise river surveying using UAV aerial photogrammetry can be achieved by establishing the base near the river using GPS from the reference point and further calibrating with ground control points. Despite the proposal of UAVs equipped with real-time kinematic (RTK) systems (i.e., RTK-drones), they have not been adopted because of their unverified accuracy. Therefore, this study aims to validate the positioning accuracy of RTK-drones to determine whether they can replace traditional reference points in river surveying. To this end, we surveyed six control points around Jinju using both GNSS and RTK-drone methods. The results showed that, with adequate stabilization time and in the absence of nearby obstacles, RTK drone surveys can reliably replace reference points, thereby reducing time and labor costs in river surveys.