SBAS Guidelines for Shipborne Receiver and EGNOS Performances based on IMO Res. A.1046 (27)

Sergio Magdaleno, Manuel López, Carlos de la Casa, Elisabet Lacarra, Nuria Blanco, David Jiménez, Kjell Arne Aarmo

Abstract:	The European Geostationary Navigation Overlay Service (EGNOS) augments the open public service offered by the GPS in Europe. EGNOS makes GPS suitable for safety critical applications. EGNOS is conceived as an integral part of a multi–modal inter–regional Satellite-Based Augmentation System (SBAS) service that integrates systems designed according to the same standard SARPs (annex 10 vol I) [3] such as US WAAS, Japanese MSAS, GAGAN in India, SDCM in Russia and KAAS in South Korea. EGNOS provides over Europe both corrections and integrity information about the GPS system, delivering opportunities for accurate positioning improving existing applications or developing a wide range of new ones. As the European SBAS, EGNOS offers three services: Open Service, Safety-of-life Service and EDAS. In general, the EGNOS Safety-of-life (SoL) Service is intended for transport applications in different domains (and currently in use by Aviation) where lives could be endangered if the performance of the navigation system is degraded below specific accuracy limits without giving notice in the specified time to alert. This requires that the relevant authority of the particular transport domain determines specific requirements for the navigation service based on the needs of that domain. A new EGNOS service for maritime applications is currently under evaluation with the objective to complement the existing maritime radionavigation systems (e.g. DGNSS) in the European region for enhanced accuracy and integrity information where there is no back-up infrastructure or in poorly covered environments. One of the steps needed for the development of this new EGNOS maritime service is the definition of a minimum set of recommendations for receiver manufacturers to provide them with a clear view on how to design their SBAS receivers to be compliant with the requirements defined for such a service. EC, GSA, ESA and ESSP SAS have been working together since 2016 to develop guidelines for manufacturers for the implementation of SBAS in shipborne receiver. These guidelines, together with a set of test specifications, were developed in the frame of the SBAS Working Group created in the Special Committee (SC) 104 on Differential Global Navigation Satellite Systems (DGNSS) of Radio Technical Commission for Maritime Services (RTCM). The aim of these guidelines is to define the minimum SBAS messages needed to be processed by a SBAS receiver for the maritime sector to be compliant with the International Maritime Organization (IMO) Resolution A.1046. This paper presents the set of SBAS message type recommended by these SBAS guidelines as well as the preliminary list of tests that must be fulfilled to be compliant. Additionally, a preliminary performance assessment of the potential EGNOS maritime service based on IMO Res. A.1046 (27) for a 24 months period during 2016, 2017 and 2018 is presented. The performance parameters are calculated using real data to show what level of performance was attained by EGNOS. The assessment was done using both EGNOS RIMS and fault-free receivers, based on these guidelines, fed with actual data. The performance is shown for each performance parameter defined in the IMO Res. A.1046 (27) and for navigation in ocean waters, coastal waters, harbour entrances and harbour approaches. The paper also includes Service Coverage maps understood as a potential initial service commitment area representing where EGNOS maritime service based on IMO Res. A.1046 (27) is fulfilling the requirements. The paper is completed with a preliminary performance assessment of EGNOS using real data collected by a receiver installed in a vessel. To compute the performances, a software receiver aligned with the SBAS guidelines recommendations is used. The data is injected in this software (in RINEX format) and the position solution according to a receiver aligned with SBAS guidelines is computed. Finally, the performances obtained with this software receiver are compared with some of the requirements of the IMO Res. A.1046 (27).
Published in:	Proceedings of the 31st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2018) September 24 - 28, 2018 Hyatt Regency Miami Miami, Florida
Pages:	1852 - 1865
Cite this article:	Magdaleno, Sergio, López, Manuel, la Casa, Carlos de, Lacarra, Elisabet, Blanco, Nuria, Jiménez, David, Aarmo, Kjell Arne, "SBAS Guidelines for Shipborne Receiver and EGNOS Performances based on IMO Res. A.1046 (27)," Proceedings of the 31st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2018), Miami, Florida, September 2018, pp. 1852-1865. https://doi.org/10.33012/2018.16114
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