PPK Processing to Boost Uas Accuracy in Cadastral Mapping

Abstract

Abstract. Unmanned Aerial Systems (UAS) are increasingly used in different applications, including 3D urban modelling, cadastral mapping, urban planning, GIS information system and other fields because of their advantages. As a consequence, UAS equipment is constantly developed to provide more accurate results in a more reliable mode. This paper aims to evaluate the performances of a low-cost UAS system, namely DJI Phantom 4 Pro v2 equipped with a TeoKIT GNSS PPK (post-processing kinematic) module for cadastral mapping purposes. Two fights (oblique and nadir) over a residential area at 60 m height were performed and some 100 ground points were used to derive RMSE accuracies. Comparison between GNSS-aided with PPK processing and indirect georeferencing processes are performed. Given a mobile laser scanner (MLS) point cloud as ground truth, comparison with UAS point clouds and manually digitized features are also performed and reported.

Enhancing LiDAR-UAS Derived Digital Terrain Models with Hierarchic Robust and Volume-Based Filtering Approaches for Precision Topographic Mapping

“…The planimetric coordinates of the ChPs were determined within the Romanian national coordinate system known as "Stereographic on a unique secant plane-1970" (STEREO-70). Furthermore, the ellipsoidal heights were converted from the ETRS89 European datum to the Black Sea-1975 normal heights, corresponding to the RO Const/NH vertical datum, as outlined in [30]. Also, 33 of these points were marked on the ground by painting two red and two white triangles, using a hand-crafted pattern of 40 cm × 40 cm.…”

“…Finally, a manual digitization process was applied on shaded Digital Surface Models (DSMs) (Section 3) to delineate the edges of building roofs. These manually digitized roof edges were then compared with edges manually digitized from orthophotos generated from a 60 m oblique UAS flight, as reported in [30] (Figure 13).…”

“…Finally, a manual digitization process was applied on shaded Digital Surface Models (DSMs) (Section 3) to delineate the edges of building roofs. These manually digitized roof edges were then compared with edges manually digitized from orthophotos generated from a 60 m oblique UAS flight, as reported in [30] (Figure 13). To evaluate the disparities between the LiDAR-derived elevation data and the elevations provided by ChPs, a mesh surface was generated based on the LiDAR-UAS point clouds using CloudCompare software.…”