An Introduction to EGNOS: The European Geostationary Navigation Overlay System

Recognizing the strategic importance of satellite navigation and its applications, a European approach was developed in the 90s. The European strategy on satellite navigation was then based on two major steps, what was known as GNSS-1 and GNSS-2, linked respectively to the European Geostationary Navigation Overlay Service (EGNOS) and Galileo infrastructures. The development of the EGNOS system, namely a Satellite Based Augmentation System (SBAS) to GPS, became the first European infrastructure devoted to GNSS. EGNOS, considered by many, as the pioneer and the stumbling block of Galileo, did allow the development of a competent European industry in GNSS and convinced Europe on the importance to achieve full autonomy on GNSS by developing their own GNSS constellation, the Galileo system. EGNOS started to provide Open services on 1st October 2009, targeting mass-market applications for non-safety of life applications. On 2nd March 2011, Safety of Life Service was started, following EC authorization to provide the service. This chapter describes the EGNOS mission, system architecture and services, complemented with some detailed information on specific fundamental aspects such as integrity, ionosphere, signal format and SBAS interoperability with other similar worldwide systems. The chapter also includes some information on EGNOS operations, performance and potential infrastructure evolutions currently under assessment. This chapter is produced for academic purposes only. Official information on the EGNOS actual system status and performances is to be obtained via the European Commission and the EGNOS Operator. Relevant official reference documents and websites (as per May 2013) are provided also throughout this chapter.