EGNOS – satellite-based augmentation in Europe

For situations where safety is critical, the European Geostationary Navigation Overlay Service (EGNOS) provides a regional augmentation for global navigation satellite systems (GNSS) such as Galileo and GPS. The EGNOS system operates over Europe and provides an integrity message for safety-of-life applications, allowing users to determine the correctness of the navigation signals they are receiving.

Consisting of three geostationary satellites and a network of over thirty ground stations, EGNOS achieves its aim by measuring the performance of received GNSS signals over Europe, and transmitting an augmentation signal to this. The augmentation signal improves the accuracy of the GNSS positioning signals (accounting for e.g. atmospheric effects), while also providing an integrity message regarding the continuity and availability of those signals.

Known as a satellite-based augmentation system (SBAS), EGNOS currently provides both correction and integrity information for the GPS system. A future evolution will include this augmentation for the European GNSS, Galileo. EGNOS is already a fundamental part of aviation and maritime operations in Europe.