NLES (Navigation Land Earth Stations)

The Project belongs to the RAMS analysis of the Navigation Land Earth Stations (NLES) which aims to demonstrate the integrity of the system, reducing the failures that can be generated in the EGNOS system following the NLES. The NLES are part of the EGNOS (European Geostationary Navigation Overlay Service) system, developed by the European Space Agency (ESA), the European Commission and Eurocontrol. EGNOS is designed as a satellite-based augmentation system that aims to correct the signals that global satellite navigation systems (GNSS) transmit to the user's GPS receiver. It also complements and provides greater accuracy and safety of GPS and GLONASS signals; it has two basic elements, the space segment [formed by geostationary satellites (GEO)], and the earth segment [consisting of Ranging and Integrity Monitoring Stations (RIMS), Mission Control Center (MCC), EGNOS Wide Area Network (EWAN) and Navigation Land Earth Stations (NLES)]. With respect to the NLES, these are responsible for sending raw data streams and generic interface data, to be relayed to users, to the Central Control Facility (CCF) that controls EGNOS. In this way they guarantee the supervision and permanent control of the service. They also receive messages prepared by the Central Processing Facility (CPF) in the Master Controller Center (MCC), for loading data flow to geostationary satellites (GEO) and generating the GPS signal. The NLES automatically select the best CPF according to their integrity and quality of service indicators (QOS), so that they can maintain stable communication between space and earth.