At least four satellites will be visible from any point of the earth at all times but in fact, as from today, there is a total of 26 making up the whole Galileo constellation. Galileo is Europe’s precise satellite-based navigation and positioning system, providing three main worldwide services: positioning and timing (the Open Service, OS), search and rescue (SAR) and the Public Regulated Service (PRS) for government-authorized users.

On 25 July at 11.25 GMT four new satellites of this program were launched from the Kourou spaceport: GSAT0219, GSAT0220, GSAT0221 and GSAT0222, more familiarly known as Tara, Samuel, Anna and Ellen. These new incorporations, bringing the constellation up to a total of 26 satellites, close the second Galileo block, endowing it with full capacity.

The program kicked off with the IOV phase (In-Orbit Validation), during which the system was tested on the basis of two experimental satellites now withdrawn (GIOVE-A and B) and the first four satellites making up the constellation. GMV played an important role in this phase, carrying out engineering tasks and complete system design.

These initial tests were followed by the intermediate or FOC phase (Full Operational Capability), designed for deploying the rest of the technology and infrastructure in both the ground- and space-segments, turning it into an operational constellation. Here GMV developed critical subsystems of the Ground Control Segment (GCS) and Ground Mission Segment (GMS), as well as the Orbit & Synchronization Processing Facility (OSPF), MDDN Network equipment (MNE), Service Product Facility (SPF) and Flight Dynamics Facility (FDF).

GMV has been the prime contractor for Galileo’s Timing and Geodetic Validation Facility (TGVF) services; it is co-leading development of the European Union’s GNSS Service Centre (GSC) and is supplying infrastructure of the SAR’s Return Link Service Provider (RLSP). Fifteen GMV employees have also been posted to the control center of the German Aerospace Center (DLR) to give in situ support for Galileo operations.

Ever since countries like the USA and Russia set up their own satellite-navigation systems, GPS and GLONASS respectively, Europe began to take the first steps towards setting up its own system (Galileo). The official starting gun for Europe’s GPS was fired in 1999 but this followed ten years of previous spadework. The European Commission is in charge of coordinating and managing program implementation, with ESA collaboration in technology design and development and also GSA to run the service and see to its safety.

The final constellation will be made up by 27 satellites plus 3 spares, 9 active and 1 spare in each of the three orbital planes (MEO). This arrangement, at an altitude of 23,222 km and satellite inclination of 56°, makes the system a rapid, efficient and high-precision technological set.