EGNOS-based positioning performance for nautical tasks and the potential of implementation in the maritime domain

Abstract

Additional corrections from augmentation systems improve the Global Navigation Satellites Systems (GNSS) position accuracy up to one to two meters. As one of the satellite based augmentation systems (SBAS) the European Geostationary Navigation Overlay Service (EGNOS) provides satellite clock, orbit as well as ionosphere corrections which improve ranging and positioning at user site. The investigation of the EGNOS Open Service in the maritime domain as an effective augmentation system for positioning and navigation is the topic of this paper. This includes a detailed positioning performance analysis as well as the future potential of implementation of EGNOS in the maritime domain. For evaluation of the EGNOS positioning performance the vessel "NAWIGATOR XXI" was travelling over 62 days in the year 2015 in the Baltic Sea. To obtain reference trajectories Precise Point Positioning (PPP) solutions were also generated. The intensive analysis results present a very high accuracy level for the position based on EGNOS corrections. The horizontal position error of GNSS augmented by EGNOS is lower than 0.9 m (95%) and fulfils many requirements of the International Maritime Organization (IMO) e.g. navigation in oceans, coastal areas, ports as well as inland waterways. Based on the individual horizontal and vertical position errors the RMS for the whole measurement campaign were calculated. These values achieved an accuracy level significantly below one meter in horizontal as well as in vertical position. Detailed and extensive analyses show that different surroundings or scenarios do almost not affect the EGNOS positioning as long as the reception of GPS and at least one EGNOS satellite is ensured. The first results of this analysis in respect of the achieved accuracy and availability emphasize a high potential of EGNOS in the maritime domain. The question therefore is how these useful augmentation data can be used by a DGPS receiver on board of a ship.