Description and Applications of EDAS (EGNOS Data Access Service).

E. Lacarra, J. Vázquez, A.J. Gavín, J. Morán, M.A. Sánchez

Abstract:	The objective of this paper is to make the GNSS community and the interested audience aware of EDAS new Services and its enhanced features. Also, examples of actual and potential applications that can be developed as well as potential benefits and performance improvements that can be achieved will be presented. Ground-based access (through the internet) to EGNOS data in real-time is now possible thanks to the EGNOS terrestrial data service: EDAS (EGNOS Data Access Service). EDAS is the single point of access for the data collected and generated by the EGNOS infrastructure which makes use of EGNOS ground stations distributed over Europe, Africa and North America. The European Commission (EC) is the EDAS program manager and ownership of the EGNOS Data Access System (EDAS), whereas ESSP (European Satellite Service provider), the EGNOS Service Provider, is the company in charge of providing the Service and GMV (Grupo Mecánica del Vuelo) is the EDAS manufacturer, developing the EDAS system evolutions. ESSP also manages the EGNOS Helpdesk, which provides technical support to users answering any potential question or clarification about EDAS, along with the registration of new EDAS users. This EGNOS helpdesk handles both phone calls and e-mails on a H24 basis. Continuous provision of EDAS Services started on 2009. On the third quarter of 2013, a new set of added value services were declared, enabling a wider range of applications. Currently, the Services provided by EDAS are the following: • Main Data Streams: EGNOS data is provided through Internet on real-time in ASN.1 format (Service Level 0), RTCM 3.0 format (SL1) and RTCM 3.1 format (SL2), covering: o Raw GPS, GLONASS and EGNOS GEO observations and navigation data received at the RIMS sites o EGNOS augmentation messages. • Data Filtering: Filtering capabilities to allow receiving EGNOS data from only certain subsets of RIMS stations when connecting to EDAS Service Level 0 and 2. • SISNET Service: EGNOS messages provided in real time using the SISNeT protocol defined by ESA. • FTP Service: Historical EGNOS data available through an FTP site, including: o EDAS SL0, SL1, SL2 raw data. o GPS/GLONASS navigation & observations (RINEX) o EGNOS messages (ems + RINEX-B) o IONEX data files • Ntrip service: RIMS raw measurements are provided in real time using Ntrip protocol. Firstly, this paper will present the current EDAS services, their main features and the observed performances during the past years. It will present the EDAS Service Definition Document (EDAS SDD) that describes its characteristics and conditions of access, along with the website in which a user can apply for the registration of these Services. It will show updated figures on the number of users subscribed to the service and the areas of activity. Secondly, the paper will shortly describe each EDAS service (main streams, data filtering, NTRIP, SISNET and FTP) and the different techniques that could be applied to improve GPS positioning accuracy, such as the application of the EGNOS messages using SISNET or the application of Kinematic and High-Accuracy Messages through the NTRIP Service. Apart from enhancing the precision of position data derived from satellite-based positioning systems, EDAS supports a variety of other applications and research programs. The added value of the EDAS services with respect to other solutions will be explained. Finally, examples and potential EDAS application in different domains will be listed. Some specific applications which are currently taking benefit from EDAS will be introduced, showing the improvements achieved in the level of accuracy and some other relevant results. Additionally, the off-line data access provided by the FTP site (satellite observation, navigation, SBAS messages and IONEX) paves the way for many other applications as, for instance, scientific studies of the atmosphere or orbit characterization.
Published in:	Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013) September 16 - 20, 2013 Nashville Convention Center, Nashville, Tennessee Nashville, TN
Pages:	2228 - 2242
Cite this article:	Lacarra, E., Vázquez, J., Gavín, A.J., Morán, J., Sánchez, M.A., "Description and Applications of EDAS (EGNOS Data Access Service).," Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013), Nashville, TN, September 2013, pp. 2228-2242.
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