CONSIDERATION TO TOPOGRAPHY SURVEY OF RIVER BED USING UAV

Accurate survey of river is essential for investigation and research of a river. This research examined how the river bed topography can be efficiently grasped using prevalent UAV (Unmanned Aerial Vehicle). Photography was performed with 90%/60% of OL/SL, 30 meters avobe-ground, and the accuracies were examined. The photogrammetory of the area of 203.6ha with 113 picture points was inaccurate. In another examination, errors (RMSEs) of the photogrammetory with 6 and 8 picture points to an area of 150m x 300m were less than 0.10m and 0.05m, respectively, the accuracies are practically sufficient. Comparing this result with a public survey manual with regard to the number of picture points, a possibility that the number could be reduced practically was shown strongly. Since the range of photographing by one flight of UAV is restricted, the photogrammetry by UAV is not suitable for a broad river but for a smaller one.