Investigators have uncovered the problems behind the failure of atomic clocks onboard Galileo satellites, the European Commission said.
For months, the European Space Agency has been investigating the reasons behind failing clocks onboard some of the 18 Galileo navigation satellites.
Each Galileo satellite has four ultra-accurate atomic timekeepers, two that use rubidium and two hydrogen maser. But a satellite needs just one working clock for the satnav to wor, the rest are spares. Read more…
Signing the contract to build another 8 Galileo satellites
Europe’s Galileo navigation constellation will gain an additional eight satellites, bringing it to completion, thanks to a contract signed at the Paris Air and Space Show.
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 qualified 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.
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.
Space-based radio navigation positioning has made significant strides in recent decades. It is now poised to make a greater leap thanks to Galileo, Europe’s global navigation satellite system (GNSS). Signalling technology developed by a team of European engineers not only helps Galileo deliver better accuracy and clear up signal clutter; it also pushes satellite navigation and its features to the next level.
A European team, led by French engineer Laurent Lestarquit and his Spanish colleague José Ángel Ávila Rodríguez and including German Günter Hein and Belgian Lionel Ries, has a unique specialism: sending clear signals from space. A virtual cacophony of radio frequencies is sent down to earth from the more than 50 navigation positioning satellites currently in orbit – including those of the US-led Global Positioning System (GPS), Russia’s Global Navigation Satellite System (GLONASS) and more recently Europe’s Galileo system. This team has helped ensure that signals do not interfere with each other, and that users and developers alike will be able to profit from the next-generation positioning technology that Galileo offers.
The team’s contribution of modulation and spread-spectrum signal technologies forms one of the joint European satellite positioning system’s core components, delivering signals that enhance accuracy, save on satellite power and ensure interoperability with GLONASS and the current GPS and its possible upgrades. Read more…
The engineering team behind the signal technology underpinning Europe’s Galileo satellite navigation system has reached the final of this year’s European Inventor Award, run by the European Patent Office.
The team is led by Spanish engineer José Ángel Ávila Rodríguez – now part of ESA’s Galileo team – and his French colleague Laurent Lestarquit from France’s CNES space agency.
The team also includes German Günter Hein, formerly head of the department studying the evolution of EGNOS and Galileo for ESA, as well as Belgian Engineer Lionel Ries, now in ESA’s technical directorate, as well as French CNES engineer Jean-Luc Issler. Read more…
As first reported last November, anomalies have been noted in the atomic clocks serving Europe’s Galileo satellites.
Anomalies have occurred on five out of 18 Galileo satellites in orbit, although all satellites continue to operate well and the provision of Galileo Initial Services has not been affected.
Highly accurate timing is core to satellite navigation. Each Galileo carries four atomic clocks to ensure strong, quadruple redundancy of the timing subsystem: two Rubidium Atomic Frequency Standard (RAFS) clocks and two Passive Hydrogen Maser (PHM) clocks. Read more…
Across the 18 satellites now in orbit, nine clocks out of 72 have stopped operating. Three are traditional rubidium devices; six are the more precise hydrogen maser instruments that were designed to give Galileo superior performance to the American GPS network.
Galileo was declared up and running in December. However, it is still short of the number of satellites considered to represent a fully functioning constellation, and a decision must now be made about whether to suspend the launch of further spacecraft while the issue is investigated. Read more…
On 01 December Galileo satellites 13 and 14 begun transmitting navigation signals as fully operational members of the constellation.
The pair were launched from Europe’s Spaceport in French Guiana on May 24 (http://galileognss.eu/galileo-liftoff-replay-soyuz-vs15/).
After launch and maneuvers to reach their final orbital altitude, their navigation and search-and-rescue payloads were methodically switched on and checked out. Their performance was assessed in relation to the rest of Galileo system. Read more…
This timelapse video shows Galileo satellites 15–18, from final preparations to liftoff on a Ariane 5 launcher, flight VA233, from Europe’s Spaceport in French Guiana, on 17 November 2016, accelerating deployment of the new satellite navigation system. Galileo is the Europe’s own global satellite navigation system. The full system of 24 satellites plus spares is expected to be in place by 2020.