A Kinematic Campaign to Evaluate EGNOS 1046 Maritime Service

Abstract

Global Navigation Satellite Systems (GNSSs) have improved the efficiency and accuracy of transportation means. In terms of safety, the European Geostationary Navigation Overlay System (EGNOS) is providing vertical and lateral guidance to civil aviation since 2011. Furthermore, EGNOS can support applications in other sectors such as maritime, railways and road. The present contribution aims to assess the use of EGNOS for maritime navigation compliant with the International Maritime Organization (IMO) requirements established in its Resolution A.1046 (27) for harbour entrances, harbour approaches and coastal waters: 99.8% of Signal Availability, 99.8% of Service Availability, 99.97% of Service Continuity and 10 m of Horizontal Accuracy. The study has selected the waters surrounding the Canary Islands, within the south west border of coverage of EGNOS, to perform a kinematic test campaign from 7th November 2018 to 21st April 2019. For this purpose, we installed a geodetic multi-frequency multi-constellation receiver-antenna pair on-board two vessels from the Armed Institute of the Spanish Civil Guard based in Tenerife. The ESA/UPC GNSS laboratory (gLAB) tool suite has processed the remotely-retrieved GNSS measurements, in conjunction with EGNOS corrections and with cleansed GPS broadcast navigation messages. EGNOS Availability and Continuity have been evaluated within the area comprised between longitudes 13oW to 19oW and latitudes 27oN to 30oN with spatial resolution of 0.1o per 0.1o. The vessel accuracy is evaluated as the difference of coordinates obtained with single-frequency EGNOS solution and the reference trajectory computed with dual-frequency Precise Point Positioning and final orbits from the International GNSS Service. The EGNOS Maritime Service met all IMO requirements in the geographic area of latitudes northern than 28oN and longitudes eastern than 16oW after reaching a Signal Availability of 99.999%, a Service Availability in 99.90% of the predefined rectangular region, and 1.06 m of Horizontal Accuracy at the 95th percentile. In contrast, the Service Continuity requirement (only required for coastal waters) was met in 62.50% of the predefined region. We conclude that the continuity risk is the most limiting factor for expanding the EGNOS Maritime Service along the coastal waters of Canary Islands, in the EGNOS south-west border of coverage.