Monitoring 3D areal displacements by a new methodology and software using UAV photogrammetry


HASTAOĞLU K. Ö. , GÜL Y. , POYRAZ F. , Kara B. C.

INTERNATIONAL JOURNAL OF APPLIED EARTH OBSERVATION AND GEOINFORMATION, cilt.83, 2019 (SCI İndekslerine Giren Dergi) identifier

  • Cilt numarası: 83
  • Basım Tarihi: 2019
  • Doi Numarası: 10.1016/j.jag.2019.101916
  • Dergi Adı: INTERNATIONAL JOURNAL OF APPLIED EARTH OBSERVATION AND GEOINFORMATION

Özet

Nowadays, a lot of different geodetic methods based on terrestrial and remote sensing (Global Navigation Satellite System-GNSS, Total Station, Lidar, ground-based radar, Synthetic-aperture radar-SAR, etc.) are used in three-dimensional (3D) monitoring of mass movements. In recent years, Unmanned Aerial Vehicle (UAV) photogrammetry has been used in monitoring large mass movements, especially landslides. In this study, the traceability of 3D areal displacements in a dump site, which is jointly used by three different open marble pits, with a new methodology based on a UAV which has advantages compared to other methods was investigated, and the results of the application were revealed by developing software specific to the methodology. In this context, a deformation network consisting of 46 specially designed plates was established as to include the area and dump benches by paying attention not to being in the locations where new dumps were made since surface topography and morphology changed continuously due to new dumps, and 3-periodic UAV flights were performed. As a result of these flights, periodic orthomosaics and digital elevation models (DEM) were produced. The special plates placed in the field were automatically detected with the software developed and 3-D coordinates of each plate were obtained. From these coordinates obtained, the velocity values of the points were' calculated using the Kalman filtering technique. The velocity values obtained by the GNSS method at the same points were used to verify the results of UAV photogrammetry and to reveal its performance. Whether the velocity values obtained by the GNSS and UAV methods could be considered as equal was determined by statistical analyses (t-test, f-test, RMSE, and VAF). As a result of these analyses, it was found out that significant velocity values greater than 1.5 x GSD (Ground Sample Distance) obtained from GNSS could be determined successfully with UAV. Furthermore, interpolation maps were generated from GNSS and UAV velocity values to compare areal displacements, and it was observed that north (n), east (e), height (up) components of maps were compatible with the correlation values of 0.92, 0.75, 0.87, respectively.