EGNOS Performance Navigation on Board Oceanographic Hespérides Vessel

Elisabet Lacarra, Teodoro Seoane, Rodrigo González, Manuel López

Abstract: This paper aims at presenting EGNOS performance computed by a GNSS receiver on board of the oceanographic Hespérides vessel, which sailed from Cartagena (Spain) to Antarctica, in order to understand the operational requirements that EGNOS can meet in the maritime sector. Hespérides is a global research vessel from the Spanish Navy (Armada Española), which is conducted by bye the Instituto Hidrográfico Nacional (Spanish Navy Hydrographic Institute). The Marine Technology Unit (UTM) is responsible for the maintenance of scientific equipment of the ship and provides technical staff for conducting oceanographic campaigns and investigations in the Polar Regions of Antarctica and the Arctic. The research is done in the frame of the National Defence Armaments Pilot Projects. Ministry of Defence of Spain along with Ministry of Transports of Spain allowed ESSP (European Satellite Services Provider) to install a receiver on board of this vessel to analyse the GNSS performance during the complete trajectory. The article will assess the EGNOS (European Geostationary Navigation Overlay Service) performance over ocean waters and harbour entrances/approaches covered by EGNOS Service area that the Hespérides vessel sailed. EGNOS augments the open public service offered by the GPS in Europe, providing better navigation positioning than GPS standalone within the service area and integrity for safety critical applications. Even if the main objective of the SBAS systems is the civil aviation community, the advantages provided by this technology can be very useful to the maritime sector. There is an interest from the Maritime community towards an EGNOS service tailored to the operational needs (IMO Res. 1046 [2]) in the European region for enhanced accuracy and integrity information, especially where there is no back-up infrastructure or in poorly covered environments. This is why, EC (European Commission) and GSA (European GNSS Agency) are assessing an EGNOS L1 maritime service with the objective to complement the existing maritime radio-navigation systems (e.g. DGNSS). It is noted that more than 90% of maritime GNSS receiver models are SBAS compatible according to their specification but there is no guidance for the implementation of SBAS in shipborne receivers, other than a sentence in IMO MSC.401 and in IEC 61108-4 (Shipborne DGPS and DGLONASS maritime radio beacon receiver equipment) allowing for its use. An IEC 61108 standard (Maritime navigation and radio-communication equipment and systems) is required to ensure and promote a proper and safe use of SBAS by the maritime community. In consequence, EC, GSA, ESA and ESSP are developing guidelines for manufacturers for the implementation of SBAS in shipborne receiver to be compliant with the operational requirements defined in International Maritime Organization (IMO) Resolution A.1046. These guidelines, together with a set of test specifications, intend to support the integration of SBAS in the standardisation process for maritime navigation and radio-communication equipment and systems within IEC framework. Firstly, the EGNOS navigation position computed by the receiver will be analysed, considering the Hespérides route from Cartagena (South of Spain), sailing along the Spanish coast, then the Atlantic Ocean up to the limits of the EGNOS service coverage area. From the one side, the EGNOS navigation errors will be obtained with respect to a reference PPP post-processed trajectory. From the other side, the EGNOS availability will be obtained, taking especial attention at the border service coverage area. The EGNOS performance results will be compared with respect to the GPS standalone solution, to better characterize the region in which EGNOS provides an enhanced navigation position. The performance obtained with the receiver will be compared with the operational requirements defined in the IMO Resolution A.1046 (27) to assess the feasibility of EGNOS for some maritime applications. As part of this study, a thorough assessment of the potential alarms triggered by a maritime receiver will be assessed. Shipborne receivers feature alarm and alert pop-ups that can appear any time during the operation. These alarms can include: RAIM status and HDOP checks. Therefore, the HDOP and RAIM protection levels will be computed during the whole path to check if an alarm would have been triggered during the trip. Furthermore, a performance assessment of EGNOS using a software receiver in line with the SBAS guidelines will be presented, showing the observed accuracy and availability results of the EGNOS navigation solution. This software application (gLAB) was developed in line with the SBAS guidelines for shipborne receivers and used for testing the proposed tests and methods. This tool can be configured in different ways to see the differences between applying some optional SBAS messages or not. Finally, a deep analysis will be done in the EGNOS coverage area for ocean waters. Based on the actual results obtained from a receiver, it will be concluded the path in which EGNOS was available, providing a reliable navigation solution with better accuracy than GPS standalone solution. The results aim at confirming that EGNOS performance is compliant with the operational requirements defined in the IMO Res. A.1046 (27) for ocean waters and harbour entrances/approaches, being beneficial for maritime community.
Published in: Proceedings of the 32nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2019)
September 16 - 20, 2019
Hyatt Regency Miami
Miami, Florida
Pages: 1613 - 1624
Cite this article: Lacarra, Elisabet, Seoane, Teodoro, González, Rodrigo, López, Manuel, "EGNOS Performance Navigation on Board Oceanographic Hespérides Vessel," Proceedings of the 32nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2019), Miami, Florida, September 2019, pp. 1613-1624.
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