CORS Network Design and Performance Evaluation in Ethiopia

The establishment of the Continuously Operating Reference Stations (CORS) network as a national positioning service enables high precision in surveying, mapping, and navigation applications due to developments in Global Navigation Satellite System (GNSS) technology. In this study, we determined the first CORS network locations in Ethiopia by taking into account factors such as accessibility, internet coverage, and the strength of the network geometry. We chose locations for about 228 stations for Ethiopia considering these factors. The real-time CORS network’s performance was validated using a network of triangles as a reference station and a virtual reference station (VRS) within the triangles. To validate the performance of the selected networks, simultaneous GNSS observations were conducted on the reference and virtual stations. We applied Wav2 software to generate GNSS observation data on VRS locations utilizing precise coordinates of reference stations processed using Bernese 5.2 GNSS software. Both the measured and generated GNSS data on VRS were compared after processing using the same software to estimate their precise coordinates. The comparison indicated standard deviations of 0.65 and 2.7 cm in the horizontal and upward directions, respectively. Therefore, this CORS network design can be used for applications that requires a three-dimensional accuracy of less than 3 cm in the central part of Ethiopia where this validation took place.