“Inside GNSS” Dee Ann Divis, January 29, 2016

Less than a month after Europe switched off most of its Loran transmitters, a problem with GPS satellite timing signal triggered alarms across the continent and caused an unknown number of outages, including the disruption of some features of critical infrastructure.

The GPS problem was caused by an error in ground software uploaded January 26 as system operators removed space vehicle number (SVN) 23 from service. The long-planned deactivation of SVN 23, the oldest of the GPS satellites, clears the way for a new satellite, the last GPS Block IIF, which is to be launched February 4.

The software problem, however, threw GPS’s coordinated universal time (UTC) timing message off by 13 microseconds, which affected the timing data on legacy L-band signals and the time provided by GPS timing receivers, said 50th Space Wing spokesman James Hodges. The problem did not appear to have affected the GPS systems’s ability to provide positioning and navigation service.

Even so the impact on timing receivers was broad, said Charles Curry, managing director and founder of Chronos Technology Ltd. in the United Kingdom. Chronos was monitoring the effect of the glitch closely because it provides timing equipment and 24/7 support to most of the major telecommunications operators in the UK, Sweden, and Denmark. It also works with firms in other industries including energy and defense.

“Every support contract that we have that involves GPS timing receivers called in to say, ‘We’ve got a problem. What’s happening?’ Curry told Inside GNSS.

The problem, he said, was widespread.

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