Introduction to EGNOS


The European Geostationary Navigation Overlay Service (EGNOS) is Europe's first venture into satellite navigation. It was developed by the European Space Agency (ESA) under a tripartite agreement between the European Commission (EC), and the European Organisation for the Safety of Air Navigation (Eurocontrol). Several air traffic service providers are supporting the development programme with their own investments. In April 2009, the ownership of the EGNOS assets have been transferred from the European Space Agency to the European Commission which now manages and finances the entry of EGNOS into the Service Provision phase

EGNOS is the European Satellite-Based Augmentation System (SBAS) that complements the Global Positioning System (GPS) system. It disseminates, on the GPS L1 frequency, integrity signals in real-time, providing information on the health of the GPS constellation. In addition, correction data improves the accuracy of the current GPS services from about 10 m to about 2 m. The EGNOS Service Area includes all European states and has the system-inherent capability to be extended to other regions, such as EU neighbouring countries, North Africa and more generally regions within the coverage of three geostationary satellites being used to transmit the EGNOS signal

The EGNOS coverage area is Western Europe, but could be readily extended to include other regions within the broadcast area of the geostationary satellites, such as Africa, Eastern European countries, Russia and most of Brazil. EGNOS is the first element of the European satellite-navigation strategy and a major stepping-stone towards Galileo, Europe's own global satellite navigation system for the future.

Correction data

As a satellite navigation augmentation system, EGNOS improves the accuracy of GPS by providing a positioning accuracy to within three metres. By comparison, someone using a GPS receiver without EGNOS can only be sure of their position to within 17 metres.

Integrity message

EGNOS also provides verification of the system’s integrity, which relates to the trust that can be placed in the correctness of the location information supplied by the navigation system. In addition, it provides timely warnings when the system or its data should not be used for navigation. Integrity is a feature which meets the demands of safety-critical applications in sectors such as aviation and maritime, where lives might be endangered if the location signals are incorrect.


EGNOS’ infrastructure consists of three geostationary satellites over Europe and a network of ground stations. Since it is based on GPS, the EGNOS signal does not require major changes to receivers. Today, many GPS receivers available on the market are also EGNOS enabled. The development of EGNOS arose from a tripartite agreement between the European Space Agency (ESA), the European Commission (EC) and Eurocontrol, the European Organisation for the Safety of Air Navigation. It is the precursor to Galileo, the global navigation satellite system (GNSS) being developed by the European Union. EGNOS and Galileo are now part of Europe’s GNSS programmes managed by the European Commission.


As EGNOS provides an unprecedented level of accuracy and reliability, new services can be developed – including for safety-critical applications – in a wide range of market segments. These include:

  • Aviation: EGNOS provides the accuracy needed to help guide pilots both en route and for runway approaches, leading to increased safety in the air for passengers and more efficiency and savings for companies. EGNOS also allows larger passenger aircraft to land at regional airports, which may not have previously been equipped to handle them.
  • Road: EGNOS is a key tool for better managing land transport in Europe, increasing both capacity and safety, whether by road or rail. Improved positioning accuracy helps companies enhance their transport logistical operations. Public operations, such as police and emergency services, can use EGNOS to improve the speed of their responses in critical situations.
  • Agriculture: Precision agriculture refers to the use of satellite navigation sensors, aerial images, and other tools to determine optimum sowing density, fertiliser cover and other inputs. The techniques allow farmers to save money, reduce their impact on the environment and increase crop yields. EGNOS provides an affordable precision solution for farmers.
  • Location-Based Services (LBS): Location-based technologies and services embedded in vehicle telematics, personal navigation devices and mobile phones will benefit from the improved accuracy provided by EGNOS. Such precision, to within three metres, will be used for services such as pedestrian applications, locating nearby friends or mobile social networking.
  • Maritime: EGNOS will improve navigation at sea and of inland waterways. It can be used for port operations, traffic control, casualty analysis, offshore exploration and fisheries management.


Source: EGNOS GSA Portal and ESSP