Ground Control System

The structure of the GALILEO Ground Control System is composed from a Navigation System Control Center (NSCC), one total net of Stations of Orbitography and Synchronization (OSS), one series of stations of tracking remote, telemetry and commando (TT&C) as illustrated in figure. Every OSS carries out of the measurements that come together sended to the NSCC to the navigation messages coming from from the GALILEO satellites, to meteorological information and other data.

On the credit side inside dell'NSCC, the Satellite Control Facilities (SCF) carries out the maintenance goddesses satellites, controls the orbits, carries out telemetry and control to distance through stations TT&C. The NSCC comprises also the Orbitography and Synchronisation Processing Facility (OSPF), the Precision Timing Station (PTS) and the Navigation Control Facility (NCF).

The OSPF calculates the ephemeres for every satellite, the offset one of the clocks to edge and carries out one predizione of these parameters in order to generate the SISA (signal in-space accuracy).

The PTS instead comprise the atomic clocks to high precision that generate the GALILEO System Time (GST), that is the reference of time of the system.

The NCF finally, is taken care to control, to monitorare and to manage the OSPF, OSS, PTS and NCF. An external interface to the system exists moreover that is taken care to manage the communication with external entities, the Service Centres Interface.