Method for establishing ground control points to realize UAV-based precision digital maps of earthwork sites

Abstract

Recently, unmanned aerial vehicle (UAV)-based survey techniques have been applied to correct and update topographic maps for earthworks. It is essential to rectify the location values by arranging ground control points (GCPs) appropriately to improve the accuracy of UAV-based 3D topographic maps of earthwork sites. Despite the importance of the GCP arrangement, there is no effective standard for the appropriate placement of GCPs. The objective of this study was to propose an optimal arrangement of GCPs for an earthwork site using UAVs. The results showed that the error was minimized (dxyz value = 0.051 m) when there were six GCPs with a mean interval of 189.0 m at the target site (410 × 310 m). When an inside GCP was added, the dxyz value could be decreased to 0.043 m. Additionally, based on the results, this study proposed the establishment of GCP standards for realizing UAV-based precision digital maps of earthwork sites. When the GCP standards proposed in this study are used in the field, it will be possible to reduce the reliance on the capabilities of the surveyor. It will also be possible to secure the accuracy of digital maps above a certain level and even improve the measurement productivity.