Abstract
Communication technology is used to transmit the error correction signal to the GPS receiver from geostationary satellites to improve the accuracy of position information provided by the receiver. This study uses GPS-Aided GEO Augmented Navigation (GAGAN) Satellite-Based Augmentation System (SBAS) GPS receiver in stand-alone mode to provide a simple and cost-effective solution with improved positional accuracy to collect the ground control points. In this study, the GAGAN receiver is operated in static mode for longer durations at International GNSS Service (IGS)—HYDE reference station, whose position is known very accurately. It is found that the GAGAN receiver can achieve accuracies of 0.3–0.6 m in position and up to 1.0 m in elevation depending on the duration of the observation meeting the requirements of many survey and engineering applications. Using the GCPs obtained by this process, orthophoto having a planimetric accuracy of 1.0 m can be generated from CARTOSAT-2E High-Resolution (HR) satellite images. The typical height accuracies of the order of 2.0 m (3–4 pixels) could be achieved from the Digital Surface Model (DSM) derived from this process.