Galileo (satellite navigation)

Galileo is a global navigation satellite system (GNSS) created by the European Union through the European Space Agency (ESA) and operated by the European Union Agency for the Space Programme (EUSPA). It is headquartered in Prague, Czechia, with two ground operations centres in Oberpfaffenhofen, Germany (mostly responsible for the control of the satellites), and in Fucino, Italy (mostly responsible for providing the navigation data). The €10 billion project began offering limited services in 2016. It is named after the Italian astronomer Galileo Galilei.

One of the aims of Galileo is to provide an independent high-precision positioning system so European political and military authorities do not have to rely on the United States GPS or the Russian GLONASS systems, which could be disabled or degraded by their operators at any time. The use of basic (lower-precision) Galileo services is free and open to everyone. A higher-precision service is available for free since 24 January 2023, previously only available to government-authorized users. Galileo is also to provide a new global search and rescue (SAR) function as part of the MEOSAR system.

The first Galileo test satellite GIOVE-A was launched 28 December 2005, while the first satellite to be part of the operational system was launched on 21 October 2011. Galileo started offering Early Operational Capability (EOC) on 15 December 2016, providing initial services with a weak signal. In October 2018, four more Galileo satellites were brought online, increasing the number of active satellites to 18. In November 2018, the FCC approved use of Galileo in the US. As of September 2024, there are 25 launched satellites that operate in the constellation. It is expected that the next generation of satellites will begin to become operational after 2026 to replace the first generation, which can then be used for backup capabilities. Most satellites of the programme were built by OHB in Bremen, Germany, with the contribution of Surrey Satellite Technology (SSTL) in Guildford, United Kingdom.

The Galileo system has a greater accuracy than GPS, having an accuracy of less than 1 m when using broadcast ephemeris (GPS: 3 m) and a signal-in-space ranging error (SISRE) of 1.6 cm (GPS: 2.3 cm) when using real-time corrections for satellite orbits and clocks.