Understanding EGNOS

MELANIE VRITSCHAN, UMBERTO GUIDA, JON WESTBROOK

Status of the EGNOS Space Segment

Today the PRN120 and PRN126 broadcast EGNOS messages; the EGNOS operation signal broadcast since July 2006 contains the Test mode Message Type MT0/2.

The PRN 124 is used by ESA and industry for the test of the EGNOS system releases.The current EGNOS signal is broadcasted by the v2.0.3 Ground Segment Configuration. Such configuration has provided a sensible improvement in the navigation performance and the system stability. The preparatory activities for the ESR v2.2 ‘Certifiable Version’ are ongoing for handover to GSA mid 2008 as part of the fi nal phase of the Initial Operation.

The EGNOS Service area is the ECAC’96, limited by 70 degree North and 40 degree East. In the framework of the ESA GNSS Support Program, new RIMS are going to be added to the existing EGNOS ground network, in order to extend his service in:

* ECAC Northern latitude – EPINOL (in two Norwegian Northern Islands)
* Mediterranean and Middle East Area – MEDA: Abu Simbel, Egypt Agadir, Morocco Tamanrasset, Algeria Tel Aviv, Israel

EGNOS certification

EGNOS represents the first European GNSS component: as such, it provides bench marking for European GNSS certification.

In the Civil Aviation domain, the European Commission’s regulations for the Single European Sky provide the rules for the EGNOS Certification for civil aviation. In this frame, the following Regulations are considered of interest for the EGNOS services provision. Such regulations are in place; their applicability for the European GNSS components is foreseen to be supervised and supported by the European GNSS Supervisory Authority (GSA).

According to the EC Regulation (EC/549/2004), laying down the framework for the creation of Single European Sky (the “Framework Regulation”), in addition to the designated Air Traffic Service providers, a navigation services provider can be individually certified. The following articles are of interest:

* Reg.549/2004, Article 2.4. ‘air navigation services’ means air traffic services; communication, navigation and surveillance services; meteorological services for air navigation; and aeronautical information services;
* Reg.549/2004, Article 2.5. ‘air navigation service providers’ means any public or private entity providing air navigation services for general air traffic;

Such definitions are applicable to the GNSS services, then such regulation, and the following derived for the same frame, are applicable to the GNSS case.

The EC Regulation 550/2004 on the provision of the Air Navigation Services in the Single European Sky (the “Service Provision Regulation”) is applicable for the certification of the EGNOS operating entity as Service Provider. According to such regulation, the EGNOS operating entity apply to the National Supervisory Authority of the Country where his principal place of business is located. Then the NSA, supported by a Notified Body if the case, release the “certifi cation of conformity” to the Common requirements (reg. 2096/2005) for the Navigation service provision of the EGNOS operating entity. Such certifi cate shows the capability to operate and control the configuration of the system according to the ICAO standards.