2019 Volume 25 Pages 237-242
In UAV photogrammetry, the installation of control points (coordinate known points used for SfM analysis) is a bottleneck for field work. Since the new UAV, DJI Phantom 4 RTK, gives high-accuracy shooting position coordinates to each image. It may be possible to without the control points depending on the device of shooting and analysis. Therefore, in this research, using Phantom 4 RTK image at multiple nadir angles and altitudes that are theoretically effective for accuracy improvement was performed, and surveying accuracy was verified using image data only.
In this research, using UAV photogrammetry which does not use the control point, it is not enough to just make the nadir angle of photographing plural, but the accuracy can be secured by pluralizing the photographing altitude. In underwater, it was shown that a refraction correction factor of 1.42 can be applied.
