The European Geostationary Navigation Overlay Service

The European Geostationary Navi – gation Overlay Service (EGNOS) signals and services are now permanently available for free for all European citizens and industries. After more than 10 years of development, its three services; Open Service, Safety of Life and Data Access Service, were respectively declared operational in 2009, 2011 and 2012. EGNOS has become the first European satellite navigation system to reach the phase of exploitation.

The EGNOS programme is managed by the European Commission, in close co-operation with the European Member States, and with the support of the European Global Navigation Satellite Systems (GNSS) Agency and the European Space Agency (ESA). The EGNOS mission has been developed based on user needs and follows standards set at international level under the International Civil Aviation Organisation (ICAO). The system was tailored to European requirements with the support of the European Air Navigation Services Providers (ANSP)s and EUROCONTROL. The certification of EGNOS is delivered by a group of European National Safety Agency (NSA) led by the French Direction de la sécurité de l’aviation civile (DSAC), and will be handed over to the European Aviation Safety Agency (EASA).

The development of the EGNOS system is currently contracted to a European industrial consortium led by Thales Alenia Space France. The operations/service provision is assured by the certified EGNOS Service Provider, ESSP SAS. A tendering procedure is on-going to procure the service provision for the period 2014-2020.

Positioning precisions

The EGNOS Open Service provides positioning precision by improving the accuracy of a Global Positioning System (GPS). In addition to receiving the GPS signals from the GPS constellation, a user equipped with a GPS/EGNOS receiver will also receive the EGNOS signals, which allow for the corrections in real-time of the GPS data. This typically improves the accuracy of the positioning to within one to two metres. By comparison, someone using a GPS receiver that is not EGNOS-enabled can only be sure of their position to within 17 metres.

In addition to the increased performance of the GPS, another main advantage for airspace users lies in the fact that EGNOS is a Satellite Based Augmentation System (SBAS) developed under international standards. Users benefit from the compatibility with other SBAS systems in the world, like the Wide Area Augmentation System (WAAS) in the United States.

European advantages

The main advantage of EGNOS is to provide vertical guidance for aircraft during approach operations in non-visual flight conditions, for example, when visibility is poor or there is a low cloud base. EGNOS Safety of Life (SoL) service makes it possible to continue these operations even during fairly poor meteorological con – ditions by guaranteeing the receiver position within limits imposed by aviation standards and by alerting the users of a service degradation via its integrity service.

It will allow European airports to strengthen their business and increase their safety, particularly small and medium-sized airports which cannot afford expensive ground-based radio navigation aids such as Instrument Landing Systems (ILS). For them, the EGNOS SoL service represents a real alternative, allowing them to increase their capacity while saving on maintenance costs of classic ground-based navigation aids. For larger airports already equipped with ground-based navigation aids, EGNOS is a means of reliable back-up navigation that also improves the safety of the passengers and crews.

For pilots and airlines, the vertical and lateral guidance offered by EGNOS reduces a major type of accident known as Controlled Flight into Terrain (CFIT), and helps reduce the delays, cancellations and diversions of flights due to bad weather conditions. In a more distant future, the continuous improvements of the performance of the EGNOS services, as well as the extension of coverage, may make it possible to apply fully automatic landing.

In summary, EGNOS can be used as a backup to other navigation aids and increase the safety of its users. And EGNOS can be used as a primary means of navigation and allows more business opportunities.

Looking beyond Europe, there is huge potential for using EGNOS in regions such as Africa, given the relatively sparse ground infrastructure available on the continent. This could be an ideal enabler to support the growing air traffic in this region in the coming years. It would assert the SBAS even more as a worldwide interoperable service.

Worldwide airport integration

The use of EGNOS within airports requires three conditions; namely the installation of SBAS enabled receivers on-board aircraft, the design of EGNOS approach procedures, and the certification of these procedures by the national authorities.

The equipage of aircraft with a certified SBAS-enabled receiver represents a challenge, given the large number of aircraft that could potentially use EGNOS. In addition, the retrofit of the aircraft with an SBAS enabled receiver must be certified. This certification process has also a cost for the airlines (an average of €20,000 per plane). EASA is putting all efforts into making this process as smooth as possible. However, aircraft manufacturers and owners and airport operators are starting to join efforts and assess the return on investment altogether, in particular by con – sidering the reduced maintenance needs for local ANSP and the increased capacity.

Airports and Air Navigation Service Providers (ANSP) also need to invest in the design of specific EGNOS approach procedures (€30,000 to €100,000 per airport). The public sector is actively proposing incentives to help this activity, such as the ACCEPTA project recently launched in the context of the seventh European framework programme.

Before publication, EGNOS-based pro – cedures have to be authorised by their National Safety Authority (NSA). For this, EGNOS has to demonstrate that it can be used as the sole means of navigation for each procedure.

In Africa, for example, where the rate of fatal accidents in aviation is 15 times higher than in Europe, satellite navigation services for aircraft landing will be a real breakthrough. Today, in fact, not all the African airports (or runways) are equipped with ground landing assistance instruments (ILS) because this kind of infra – structure is complex and costly to maintain.

By using EGNOS existing airports, even in the most remote regions, could vastly increase their safety, with a real impact on regional integration, economic exchanges and development.

The Republic of South Africa and the Agence pour la Sécurité de la Navigation aérienne en Afrique et à Madagascar (ASECNA) – 18 African countries all together – are keen to reap these socio-economic benefits and operational savings and, together with the European Commission, are investigating how to provide EGNOS services over their regions. Moreover, in areas such as the North-African coast of Morocco and Tunisia, where the EGNOS signal is already available, landing procedures are being developed, anticipating the future certification of the Safetyof- Life (SoL) service over this region.

Airport support

The airport industry is mainly composed of ANSPs and airport operators. EGNOS has received their genuine and constant support since its launch in 1998, mainly via the EGNOS Operator and Infrastructure Group (EOIG). This group is composed of eight ANSPs covering 70 per cent of the European airspace plus the French National Space Agency (CNES).

Today, seven of these ANSPs from the EOIG have decided to create the ESSP SAS; a company that has been operating EGNOS since 2009 as a certified EGNOS service provider. The implementation of EGNOS in regional airports is well on its way. As an example, the regional company Aurigny Airlines has successfully started to operate commercial flights at Alderney Airport, in Guernsey, demonstrating the direct benefits of EGNOS.

At the end of 2012, Europe will have published more than 100 SBAS approach procedures. This should rapidly evolve as the equivalent SBAS Wide Area Augmentation System (WAAS) in the United States published more than 6,000 procedures in 2011.

Complementing SESAR

EGNOS is a key input to the Single European Sky initiative (SESAR) and, as a Public Private Partnership (PPP), is developing a long-term vision for air navigation. EGNOS is already a central infrastructure element of the transition to performance-based navigation (PBN) which will bring additional improvements. It will play an even bigger role by serving new types of applications both in the navigation and surveillance domains.

Together with SESAR, EUROCONTROL is also a key player in implementing performance-based navigation under the Single European Sky and transitioning towards the use of EGNOS. Continuing to develop synergies between the European Commission, the GSA, EUROCONTROL and SESAR is essential for maximising the benefits of EGNOS.

Challenges

The challenge faced by the European Commission was to organise the transition from a system under development from the aegis of ESA to the provision of safety-critical services. This will ultimately fine-tune the technical performances of the system, finalise the safety demonstrations and monitor the certification of the service provider, whilst procuring the contracts for the continuity of the services with industry. It has also required us to define a liability scheme in case of incidents.

The hand-over of the programme between ESA and the Commission was accomplished in April 2009. The certification of the EGNOS service provider was achieved in July 2010, and respectively the Open Service, the Safety of Life Service and the EDAS Service of EGNOS were declared in October 2009, March 2011, and July 2012 by the Commission.

The environmental impact

The EGNOS SoL Service will lower the environmental impact of air traffic by allowing a curved approached, leading to lower fuel consumption and reduced noise levels for people living within the neighbourhood of airports. EGNOS also reduces the risks of delays and diversion to an alternate airport in case of bad weather and this also has a positive environmental effect, reduces fuel consumption and inconvenience for airspace users.

About the author

European Commission Vice-President Antonio Tajani has been working on the frontline of European politics for the past two decades. He was appointed to the Commission in 2008, starting with the transport portfolio and then taking charge of Industry and Entrepreneurship in February 2012. From 1994 to 2008, Antonio was a Member of the European Parliament. In 1999 he was chosen as the leader of the Forza Italia party in the European Parliament and elected to the Presidency of the European People’s Party-European Democrats in 1999.