An event marked the completion of the in-orbit testing of the first two Galileo satelliteson 29 March at ESA’s Redu Centre in Belgium. By attending the event, media had the chance to learn more about the programme and its progress from ESA, the EC and the industrial partners.
The first two operational Galileo satellites were launched on 21 October 2011. Since then, they have been extensively tested to verify that their sophisticated navigation payloads are performing well, including detailed measurements of their ten different navigation signals across three radio bands.
The campaign is centred on Redu, which is the ESA centre that traditionally checks the health of ESA’s telecommunication satellites. But Galileo is a whole new class of European satellite, and Redu was specially equipped for its evaluation.
A new 20 m-diameter antenna has examined Galileo’s navigation signals in all the fine detail needed, even from 23 222 km away in space. A smaller antenna has tested both the downlinking of satellite telemetry and uplinking of commands. A UHF transmitter has sent simulated distress calls to the satellites, simulating the scenarios where the operational Galileo system will relay calls to the authorities to speed up search and rescue.
Test receivers just like those for everyday users were also set up at Redu and elsewhere, working just as they will once Galileo starts initial services in 2014. While Redu was the geographic focus, the test campaign spanned Europe and the globe.
The satellites are controlled from the Galileo Control Centre in Oberpfaffenhofen near Munich in Germany, while a second control centre in Fucino, Italy, is responsible for the navigation payloads and the services they provide. A worldwide network of ground stations is in place to continuously check the accuracy of Galileo signals, from tropical Noumea in New Caledonia to Troll base atop an icebound Antarctic peak.
Now that the satellites have been given a clean bill of health, they can be used to assess the performance of this worldwide Galileo ground segment network deployed to date. More generally, the test results set a benchmark to follow throughout the satellites’ 12-year operational lives and act a reference for the rest of the Galileo constellation set to follow the first two satellites into space.
This effort is part of the validation phase of Galileo. Started with the first two operational satellites, it will continue once the next two satellites are launched at the end of summer. With four satellites in space and the ground network operating, it will confirm that Galileo works as designed and is fully interoperable with the US GPS system.
More Galileo satellites are coming in 2013. The 14-strong constellation will begin offering initial navigation services in 2014. Redu will play a similar health-checking role for all of these Galileo satellites.
Source: ESA