3D Flight Planning and Data Analysis of Aerial Photographs taken with an Unmanned Aerial Vehicle

Abstract

UAVs, equipped with optical cameras and GPS, are used to obtain high quality aerial photographs. The photos are processed with photogrammetric techniques. Therefore, e"cient flight planning is required. Horizontal flight paths for photogrammetry are optimized by open source programs like the Mission Planner from Ardupilot. When the topography is mountainous or steep, the current flight planning is not ideal. For that reason, a program is written to optimize the flight planning for complex topography. The idea is that the way points lay smoothed and parallel to the landscape surface. Calculated flight plans are tested successful in Attinghausen, Canton of Schwyz and Grimsel, Canton of Berne. Calculated way points and GPS data were compared after the flight to obtain the nearest distance to the ground. The resulting aerial photographs are used to produce a three-dimensional photogrammetric model, an orthophoto and a DEM per flight. Agisoft Photoscan was mainly used for this. The new DEM from Agisoft is compared with the swissALTI3D (older DEM) from swisstopo. Such comparisons are usually applied to detect mass changes. Adam Tech 3DM Analyst is also used to create photogrammetric data of one flight. Orthophotos and DEM of both softwares show good quality with resolutions till 5 mm per pixel.