VRS GPS supported bundle adjustment with self-calibration for unmanned aerial vehicle images

Abstract

UAV (Unmanned Aerial Vehicle) is currently used in civil purpose such as mapping and disaster monitoring. One of UAV advantages is to collect high resolution images for mapping. However, due to payload limitations of UAV, it is difficult to mount metric aerial camera and precise POS (Positioning and Orientation System) device. Instead, only the non-metric camera and the low-cost POS device can be installed. For mapping demands, the Trimble BD970 GNSS OEM board will be carried on the UAV to collect the L1/L2 carry phase measurements during fight time for promoting the flying trajectory accuracy by VRS (Virtual Reference Station) GPS technique. Meanwhile bundle adjustment with self-calibration will be employed for AT (Aerial Triangulation) to overcome the imperfect calibration of non-metric camera by the close-range photogrammetric approach. The offset between image perspective center and GPS antenna center, called GPS antenna offset, has to be faced even though the VRS GPS can provide the flying trajectory information in centimeter level. Therefore, the drift parameters will be utilized to solve the GPS antenna offset problem while performing bundle adjustment with self-calibration, i.e. AT, for precise positioning and orientation of UAV images. All in all, this study will discuss the feasibility of high-accuracy GPS supported AT for UAV images to promote the mapping possibility for UAV images in the future.