GALILEO UPDATE

Additional eight satellites for Galileo

Europe’s Galileo navigation constellation will gain an additional eight satellites, bringing it to completion, thanks to a recently signed contract. The contract to build and test another eight Galileo satellites was awarded to a consortium led by prime contractor OHB, with Surrey Satellite Technology Ltd overseeing their navigation platforms.

This is the third such satellite signing: the first four In Orbit Validation satellites were built by a consortium led by Airbus Defence and Space, while production of the next 22 Full Operational Capability (FOC) satellites was led by OHB.

These new batch satellites are based on the already qualifi ed design of the previous Galileo FOC satellites, except for changes on the unit level – such as improvements based on lessons learned and reacting to obsolescence of parts. http://www.esa.int

Two more satellites join Galileo working constellation

Two further satellites have formally become part of Europe’s Galileo satnav system, broadcasting timing and navigation signals worldwide while also picking up distress calls across the planet.

These are the 15th and 16th satellites to join the network, two of the four Galileos that were launched together by Ariane 5 on 17 November, and the fi rst additions to the working constellation since the start of Galileo Initial Services on 15 December. The launch into space and the manoeuvres to reach their fi nal orbits still left a lot of rigorous testing before the satellites could join the operational constellation.

Their navigation and search and rescue payloads had to be switched on, checked and the performance of the different Galileo signals assessed methodically in relation to the rest of the worldwide system.

This lengthy testing saw the satellites being run from the second Galileo Control Centre in Oberpfaffenhofen, Germany, while their signals were assessed from ESA’s Redu centre in Belgium, with its specialised antennas.

The tests measured the accuracy and stability of the satellites’ atomic clocks – essential for the timing precision to within a billionth of a second as the basis of satellite navigation – as well as assessing the quality of the navigation signals.

Oberpfaffenhofen and Redu were linked for the entire campaign, allowing the team to compare Galileo signals with satellite telemetry in near-real time.

Making the tests even more complicated, the satellites were visible for only three to nine hours a day from each site.

The satellites are now broadcasting working navigation signals and are ready to relay any Cospas–Sarsat distress calls to regional emergency services. https://phys.org/