The European Commission has officially launched the EGNOS Safety-of-Life Service for aviation, providing a new means of increasing air transport efficiency and safety. The EGNOS system enables safe landing approaches in difficult weather and topographic conditions, without any ground infrastructure, rendering air navigation safer while reducing delays, diversions and flight cancellations.
Nowadays, satellite navigation applications are playing key roles for businesses and citizens alike. The most recent available figures show that in 2009, 6-7% of the EU’s GDP, or about €800 billion, depended either directly or indirectly on these applications, which concern a wide variety of sectors, ranging from transport and security to agriculture, energy and social services.
EGNOS, the European Geostationary Navigation Overlay Service, is a satellite-based augmentation system that improves the accuracy of positioning information given by GPS, by correcting errors caused by various factors, including atmospheric disturbances. EGNOS also disseminates integrity signals in real-time, providing information on the health of the GPS constellation, a vital function for safety-critical applications.
EGNOS was developed by the European Space Agency (ESA) under an agreement with the European Commission and the European Organisation for the Safety of Air Navigation (Eurocontrol). Since 2008, work on the EGNOS system has been financed entirely under the EU budget.
The EGNOS 'Open Service' was launched in October 2009, serving applications such as personal navigation and precision farming. Today, EGNOS services are being delivered in all 27 EU member states. Switzerland and part of Norway are also covered.
Following an exhaustive certification and verification process, including many actual flight trials under different conditions at various European airports, the EGNOS 'Safety-of-Life' service is now available for use in aviation.
At the launch of the service, European Commission Vice-President Antonio Tajani, responsible for Industry and Entrepreneurship, said: “Europe’s first contribution to satellite navigation, EGNOS, will considerably increase the safety of air navigation, providing economic benefits to airports and airlines and helping to reduce CO2 emissions.”
The system’s expected benefits for airports, airlines, businesses and citizens include:
To use the new Safety-of-Life service, airports must have EGNOS-specific landing procedures for their runways and aircraft need to be equipped with EGNOS-enabled receivers.
Today, there are a number of global satellite navigation systems already in operation or soon to come online. They include the American 'GPS' system, which many people are already familiar with, the Russian 'Glonass' system, currently being upgraded, and the emerging Chinese 'Compass' system. In addition, there are a number of regional augmentation systems, such as EGNOS, the American WAAS system and Japan's MSAS, all of which improve the accuracy of positioning information given by the global systems.
EGNOS is the precursor to Galileo, the European global satellite navigation system, which will deliver a highly accurate, guaranteed civilian positioning service, whereas the American and Russian systems are both under military control.
Discussions on a European system started in the late 1990s and, in 1999, the Council called on the European Commission to develop a global satellite navigation system to be managed by public civil authorities. Once fully deployed, the Galileo system will comprise 30 satellites and a wide array of associated ground infrastructure. Under the current timetable, three initial Galileo services will be delivered from 2014/2015, including an initial Open Service, a Public Regulated Service and a Search and Rescue Service. The Galileo Safety-of-Life Service and a Commercial Service will be tested starting in 2014.
While providing autonomous navigation and positioning services, the system established under the Galileo programme will also be interoperable with GPS and GLONASS. This is an important point that was highlighted at the recent Satellite Navigation Summit in Europe, which saw American, Russian, Chinese and European GNSS decision-makers pledging close co-operation to ensure the compatibility and interoperability of all global satellite navigation systems, the idea being that any given user should have seamless access to any and all satellite navigation signals using one and the same signal receiver.
The availability of the EGNOS Safety-of-Life service marks an important step in Europe's presence in the satellite navigation market, indicates Tajani, who notes: “EGNOS is the result of a successful collaboration between the European Union, the European Space Agency and industrial partners. We, therefore, have the basis and the model to ensure an even more successful collaboration as we move towards the deployment of the Galileo system.”
Satellite navigation is based on the principle of triangulation, i.e. if you know your exact distance from three different points, you can calculate your position. The Global Navigation Satellite System (GNSS) works on this basic principle. This means that four satellites in view are necessary to determine your exact position on or above the Earth. However, each additional satellite in view further improves accuracy.
Determination of location depends on measurement of the distances between the receiver and satellites, and that depends on precise measurement of signal travel time. A GNSS receiver determines its distance from each satellite in view by measuring the time taken for the signal to travel from the satellite. As signals travel at the speed of light, travel times are tiny fractions of a second. An extremely accurate timing system is needed to do this, hence the atomic clocks in GNSS satellite constellations.
Of course, it is only possible to determine a location on Earth if you know the precise location of the satellites. This is achieved by placing satellites in highly stable medium-earth orbits (MEOs) at an altitude of about 20 000 km.
‘Satellite Navigation’ Unit,
Directorate-General for Enterprise and Industry