While Global Navigation Satellite Systems (GNSS) serve as a fundamental positioning technology for autonomous ships in Inland Waterways (IWW), in order to compensate for unexpected signal outages from constellations due to structures such as bridges and high buildings, it is not uncommon to use a sensor fusion setup with GNSS and Inertial Measurement Units (IMU)/Inertial Navigation Systems (INS). However, the accuracy of this fusion relies on the accuracy of the main localization technology itself. In Europe, Galileo and the European Geostationary Navigation Overlay Service (EGNOS) are two satellite navigation systems under civil control and they provide European users with independent access to a reliable positioning satellite signal, claiming better accuracy
than what is offered by other accessible systems. Therefore, considering the potential utilization of these systems for autonomous navigation, in this paper, we discuss the results of a case study for benchmarking the accuracy of Galileo and EGNOS in IWW. We used a Coordinate Measurement Machine (CMM) and a sub-cm Real-Time Kinematic (RTK) service which is available in Flanders to quantify the benchmark reference. The results with and without sensor fusion show that Galileo has a better horizontal accuracy profile than standalone Global Positioning System (GPS), and its augmentation with EGNOS is likely to provide European IWW users more accurate positioning levels in the future.