Implementation and Validation of a High Accuracy UAV-Photogrammetry Based Rail Track Inspection System
The regular inspection of the crane tracks of storage cranes at the Container Terminal Altenwerder (CTA), Hamburg requires high accuracy of measurements to determine its position. The allowed tolerances are in the range of 10 mm in the XY plane on a track length of 300 m. The traditional semi-automatic surveying methods are slow and require the interruption of the activities in the storage blocks. The research project AeroInspekt proposed a fully automatic measurement of the position of the tracks using UAV-based photogrammetry. In this paper, the results of the test campaign, carried out in June 2020, were presented where different cameras (150 mm and 80 mm telelens) and flight speeds (1.1 m/s and 1.9 m/s) at a 35 m flying height were performed. Furthermore, an automated rail delineation in the derived surface model was developed and evaluated with ground reference measurements. The results show that the required accuracy of the rail position with an RMSE of 3 mm in XY plane and 8 mm in altitude can be achieved with comparatively less disruption of regular block activities.