Geometric accuracy improvement of WorldView-2 imagery using freely available DEM data

This paper provides geometric accuracy improvements for very high resolution WorldView-2 (WV2) Ortho Ready Standard Level-2A (ORS2A) satellite images in the panchromatic (PAN) band. The entire process can be divided into two steps: (1) sensor orientation, which was conducted on 40 ground control points (GCPs) to determine which sensor model was best depending on various numbers of GCPs; and (2) orthorectification, whose main objective was to compare the accuracy of the process when using different freely available global digital elevation models (DEMs). The research showed that a sensor model based on rational polynomial coefficients (RPCs) with a shift or zero-order bias correction attained the best geopositioning accuracy during the orientation step with the use of seven GCPs. The highest accuracy was achieved for images orthorectified with the ALOS World 3D-30 m DEM (AW3D30).