A satellite navigation or satnav system is a system that uses satellites to provide autonomous geopositioning. A satellite navigation system with global coverage is termed global navigation satellite system (GNSS). As of 2023, five global systems are operational: the United States's Global Positioning System (GPS), Russia's Global Navigation Satellite System (GLONASS), India's Indian Regional Navigation Satellite System (IRNSS), China's BeiDou Navigation Satellite System (BDS), and the European Union's Galileo.

The European Geostationary Navigation Overlay Service (EGNOS) is a satellite-based augmentation system (SBAS) developed by the European Space Agency and EUROCONTROL on behalf of the European Commission. Currently, it supplements the GPS by reporting on the reliability and accuracy of their positioning data and sending out corrections. The system will supplement Galileo in a future version.