Galileo update

ESA communication team hands off responsibility to GSA

After four years of work, the European Space Agency (ESA) team tasked with keeping the world informed on the status of the Galileo satellite navigation system has formally passed on its responsibility to a European Union agency. This shift is part of a wider transfer of responsibilities, as this month see the official handover of the running of the Galileo system from ESA to the European Global Navigation Satellite System Agency (GSA).

The very first Notice Advisory to Galileo Users (NAGU) was issued in June 2013, just three months after the first Galileo positioning fix was achieved, to a then small community of researchers and industrial users, interested in making tests with the newborn four-satellite constellation. A total of 189 NAGUs were issued under ESA oversight in the last four years, as the constellation grew to its current 18 satellites. The user base increased dramatically from 86 to 774 registered users on the European GNSS Service Centre website as companies worked to prepare Galileo-ready products and then, on 15 December 2016, Galileo’s Initial Services began operating.

Europe’s Galileo satnav identifies problems behind failing clocks

For months, the European Space Agency— which runs the programme—has been investigating the reasons behind failing clocks onboard some of the 18 navigation satellites it has launched for Galileo. Each Galileo satellite has four ultraaccurate atomic timekeepers, two that use rubidium and two hydrogen maser. But a satellite needs just one working clock for the satnav to work— the rest are spares. Three rubidium and six hydrogen maser clocks were not working, with one satellite sporting two failed timekeepers.

“The main causes of the malfunctions have been identified and measures have been put in place to reduce the possibility of further malfunctions of the satellites already in space,” commission spokeswoman Lucia Caudet said.

ESA found after an investigation that its rubidium clocks had a faulty component that could cause a short circuit, according to European sources. The investigation also found that operations involving hydrogen maser clocks need to be controlled and closely monitored, the same sources said.

The agency has taken measures to correct both sets of problems, the sources added, with the agency set to replace the faulty component in rubidium clocks on satellites not yet in orbit and improve hydrogen maser clocks as well.

“The supply of the first Galileo services has not and will not be affected by the malfunctioning of the atomic clocks or by other corrective measures,” Caudet said, and that the malfunctions have not affected service performance. Read more at: https://phys.org.