Utilizing Airborne LiDAR and UAV Photogrammetry Techniques in Local Geoid Model Determination and Validation

• Published in: ISPRS international journal of geo-information Vol. 9; no. 9; p. 528
• Main Authors: Erol, Serdar, Özögel, Emrah, Kuçak, Ramazan Alper, Erol, Bihter
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.09.2020
• Subjects: Accuracy; Aerial photography; airborne LIDAR; Algorithms; Artificial satellites in navigation; Digital elevation models; digital terrain model; Drone aircraft; Geoid; Geoids; Geomorphology; georeferencing; Geospatial data; Global navigation satellite system; Gravimetry; Gravity; Lasers; Lidar; local geoid; Measurement techniques; Methods; Model accuracy; Navigation; Navigational satellites; Optical radar; Performance evaluation; Photogrammetry; Software; Terrain models; Three dimensional models; Topography; UAV photogrammetry; Unmanned aerial vehicles; vertical datum; Turkey
• DOI: 10.3390/ijgi9090528
• ISSN: 2220-9964

This investigation evaluates the performance of digital terrain models (DTMs) generated in different vertical datums by aerial LiDAR and unmanned aerial vehicle (UAV) photogrammetry techniques, for the determination and validation of local geoid models. Many engineering projects require the point heights referring to a physical surface, i.e., geoid, rather than an ellipsoid. When a high-accuracy local geoid model is available in the study area, the physical heights are practically obtained with the transformation of global navigation satellite system (GNSS) ellipsoidal heights of the points. Besides the commonly used geodetic methods, this study introduces a novel approach for the determination and validation of the local geoid surface models using photogrammetry. The numeric tests were carried out in the Bergama region, in the west of Turkey. Using direct georeferenced airborne LiDAR and indirect georeferenced UAV photogrammetry-derived point clouds, DTMs were generated in ellipsoidal and geoidal vertical datums, respectively. After this, the local geoid models were calculated as differences between the generated DTMs. Generated local geoid models in the grid and pointwise formats were tested and compared with the regional gravimetric geoid model (TG03) and a high-resolution global geoid model (EIGEN6C4), respectively. In conclusion, the applied approach provided sufficient performance for modeling and validating the geoid heights with centimeter-level accuracy.