ABSTRACT: This paper intends to provide results from ?EGNOS Performance Improvement in Southern Latitudes? (EPISOL) project. EPISOL is performed by the Greek company GEOTOPOS S.A. under a contract with the European Space Agency (ESA). EPISOL project aims at analysing, testing and validating the European SBAS EGNOS (European Geostationary Navigation Overlay Service) performance, by outpointing advantages and limitations. It has been designed and operated in a very complicated and demanding environment, the Aegean Sea (Greece, Southern Europe), in which a huge amount of commercial and cruise vessel routes are scheduled daily. Technically, EPISOL also exploits the possibility of EGNOS data collection through other means than the direct Signal in Space (SiS), such as SiSNet (Signal in Space through interNet). Results from this project will form a solid basis towards navigation service improvements and safety enhancements for highly demanded maritime applications, providing important information about EGNOS performance at the edge of the system's service area. In this frame, EPISOL includes a significant number of trials and collection of a large amount of data on coasting vessels in the Aegean before and after the operation of EGNOS Ranging and Integrity Monitoring Station (RIMS) in Athens. As EGNOS data analysis illustrates the European SBAS performance, arguably well-established GNSS navigation techniques, such as GPS RTK, offer reference trajectories for direct comparisons on the position domain.

KEYWORDS: Global Navigation Satellite System (GNSS), EGNOS, Accuracy of Position, Southern Latitudes, Ranging and Integrity Monitoring Station (RIMS), GPS RTK, Horizontal Position Errors (HPE), Vertical Position Errors (VPE)

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