Galileo satellite in orbit
Two further satellites, GSAT0207 (SV ID 07) and GSAT0214 (SV ID 05), increasing the total number to 16, 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 last November (images), and the first additions to the working constellation since the start of Galileo Initial Services in December.
Liftoff of Galileo quartet
The growing number of Galileo users around the world will draw immediate benefit from the enhanced service availability and accuracy brought by these extra satellites, said the European Space Agency (ESA).
The launch into space and the maneuvers to reach their final 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 center in Belgium, with its specialized 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.
Galileo’s 20-m Redu antenna
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. Now that these two satellites are part of the constellation, the remaining pair from the Ariane 5 launch, GSAT0212 (SV ID 03) and GSAT0213 (SV ID 04), is similarly being checked to prepare them for service.
Galileo satellites GSAT0207 and GSAT0214 were officially commissioned for operational use and are usable for service provision since 29 May. See NAGU 2017017 and NAGU 2017018.