Editing Galileo (satellite navigation) (section)

== Clock failures ==
In January 2017, news agencies reported that six of the [[hydrogen maser|passive hydrogen masers (PHM)]] and three of the [[Rubidium standard|rubidium]] [[Atomic clock|atomic clocks (RAFS)]] had failed; four of the full operational satellites had each lost at least one clock, but no satellite had lost more than two. The operation was not affected as each satellite is launched with four clocks (2 PHM and 2 RAFS). <ref name="clock failures2">{{cite web|url=http://www.esa.int/Our_Activities/Navigation/Galileo_clock_anomalies_under_investigation|title=Galileo clock anomalies under investigation|publisher=European Space Agency (ESA)|date=19 January 2017|access-date=19 January 2017}}</ref><ref>{{cite web|url=https://www.yahoo.com/tech/atomic-clocks-failed-onboard-galileo-navigation-satellites-103538395.html|title=Atomic clocks 'failed' onboard Galileo navigation satellites|date=18 January 2017|access-date=19 January 2017|publisher=Agence France-Presse AFP|archive-date=18 January 2017|archive-url=https://web.archive.org/web/20170118230831/https://www.yahoo.com/tech/atomic-clocks-failed-onboard-galileo-navigation-satellites-103538395.html|url-status=dead}}</ref><ref name="clock failures"/> [[SpectraTime]], the Swiss producer of both on-board clock types, declined to comment.<ref name="clock failures3">{{cite web|url=http://spacenews.com/rash-of-galileo-clock-failures-cast-doubt-on-timing-of-upcoming-launches|title=Rash of Galileo clock failures cast doubt on timing of upcoming launches|publisher=spacenews.com|date=19 January 2017|access-date=29 January 2017}}</ref> According to [[European Space Agency|ESA]], they concluded with their industrial partners for the rubidium atomic clocks that some implemented testing and operational measures were required. Additionally some refurbishment is required for the rubidium atomic clocks that still have to be launched. For the passive hydrogen masers operational measures are being studied to reduce the risk of failure.<ref name="clock failures2"/> China and India use the same SpectraTime-built atomic clocks in their satellite navigation systems. ESA contacted the [[Indian Space Research Organisation]] (ISRO) who initially reported not having experienced similar failures.<ref name="clock failures3"/><ref name="clock failures"/> However, at the end of January 2017, Indian news outlets reported that all three clocks aboard the [[IRNSS-1A]] satellite (launched in July 2013 with a 10-year life expectancy) had failed and that a replacement satellite would be launched in the second half of 2017: these atomic clocks were said to be supplied under a four-million-euro deal.<ref>{{cite web|url=http://defencenews.in/article/ISRO-readies-replacement-satellite-after-clock-failure-283932|title=ISRO readies replacement satellite after clock failure|website=defencenews.in|access-date=22 September 2017|archive-date=22 September 2017|archive-url=https://web.archive.org/web/20170922194216/http://defencenews.in/article/ISRO-readies-replacement-satellite-after-clock-failure-283932|url-status=dead}}</ref><ref>{{cite news|url=http://indianexpress.com/article/technology/science/isro-irnss-1h-readies-replacement-satellite-irnss-1h-after-clock-failure-4818259/|title=ISRO readies replacement satellite after clock failure|date=29 August 2017|work=The Indian Express|access-date=22 September 2017}}</ref><ref>{{cite news |url=http://www.thehindu.com/news/national/Atomic-clocks-on-indigenous-navigation-satellite-develop-snag/article17114134.ece|title=Atomic clocks on indigenous navigation satellite develop snag|last=D.S. |first=Madhumathi|work=The Hindu|access-date=6 March 2017}}</ref><ref>{{cite web|url=https://thewire.in/103934/atomic-clock-rubidium-irnss/|title=3 Atomic Clocks Fail Onboard India's 'Regional GPS' Constellation|last=Mukunth|first=Vasudevan|website=thewire.in|access-date=6 March 2017}}</ref>

In July 2017, the [[European Commission]] reported that 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.<ref>{{cite news|url=http://gadgets.ndtv.com/science/news/galileo-satnav-atomic-clock-failure-esa-investigation-1720170|title=Europe's Galileo Satnav Identifies Problems Behind Failing Clocks|work=NDTV Gadgets360.com|access-date=22 September 2017}}</ref><ref name="clock failures4">{{cite web|url=https://phys.org/news/2017-07-europe-galileo-satnav-problems-clocks.html|title=Europe's Galileo satnav identifies problems behind failing clocks|publisher=phys.org|date=21 July 2017|access-date=15 September 2017}}</ref> According to European sources, ESA took measures to correct both identified sets of problems by replacing a faulty component that can cause a short circuit in the rubidium clocks and improve the passive hydrogen maser clocks as well on satellites still to be launched.<ref name="clock failures6">{{cite web|url=https://tribune.com.pk/story/1449890/europes-galileo-satnav-identifies-problems-behind-failing-clocks/|title=Europe's Galileo satnav identifies problems behind failing clocks|publisher=AFP-The Express Tribune|date=4 July 2017|access-date=15 September 2017}}</ref>

=== Outages ===
==== 2019 ====
From 11 July till 18 July 2019, the whole constellation experienced an "unexplained" signal outage<ref>{{cite web|url=https://www.gpsworld.com/galileo-down-over-weekend/|title=Galileo down over weekend|date=14 July 2019|website=GPS World|access-date=14 July 2019}}</ref><ref>{{cite web|url=https://www.bbc.co.uk/news/science-environment-48985399|work=[[BBC News]]|title=Galileo sat-nav system experiences service outage |first=Jonathan|last=Amos|date=15 July 2019}}</ref> with all active satellites showing "NOT USABLE" status on the Galileo status page.<ref>{{cite web|url=https://www.gsc-europa.eu/system-status/Constellation-Information|archive-url=https://web.archive.org/web/20190714102648/https://www.gsc-europa.eu/system-status/Constellation-Information|url-status=dead|archive-date=14 July 2019|title=Constellation Information {{!}} European GNSS Service Centre|date=14 July 2019|access-date=14 July 2019}}</ref> The cause of the incident was an equipment malfunction in the Galileo ground infrastructure that affected the calculation of time and orbit predictions.<ref>{{cite web|url=https://www.gsc-europa.eu/news/galileo-initial-services-have-now-been-restored|title=Galileo Initial Services have now been restored &#124; European GNSS Service Centre|website=www.gsc-europa.eu}}</ref>

==== 2020 ====
On 14 December 2020, starting at 0:00 UTC, Galileo experienced a system-wide performance degradation lasting for 6 hours.<ref>{{cite web|url=https://www.gsc-europa.eu/news/galileo-nominal-service-restored|title=Galileo nominal service restored|date=14 December 2020|website=European GNSS Service Centre|access-date=13 Jan 2021|archive-date=27 September 2022|archive-url=https://web.archive.org/web/20220927204349/https://www.gsc-europa.eu/news/galileo-nominal-service-restored|url-status=dead}}</ref> GNSS receivers ignoring a 'marginal' status flag in the Galileo data could have experienced a pseudorange error of up to almost 80 km. The problem was related to an abnormal behaviour of a ground segment atomic clock in the time determination function of the system. The system uses parallel functioning Precise Timing Facilities in the Fucino and Oberpfaffenhofen Galileo Control Centres, and an issue occurred in Fucino whilst maintenance was performed on the parallel system in Oberpfaffenhofen.<ref>{{cite web|url=https://www.gsc-europa.eu/news/further-information-on-the-event-of-14th-december|title=Further information on the event of 14th December|date=15 December 2020|website=European GNSS Service Centre|access-date=13 Jan 2021}}</ref>