Decommissioned GPS Satellite Knocked Out UK Digital Radio Broadcasts

Problems with digital radio broadcasts in the UK last week have been blamed on a Global Positioning System (GPS) network bug.

The problems started with a US GPS satellite that caused a software error after the US Air Force removed it from service.

The BBC reported that one its own engineers confirmed that the GPS satellite caused problems for listeners when it was decommissioned.

Rogue

“The outages were caused by a rogue GPS satellite (SVN23), which was taken out of service in the evening of January 26,” said a BBC spokesperson.

The BBC also reports that “several other” satellites were affected.

Digital radio listeners in the UK took to the Digital Spy forums to complain.

“I live on the Worksop side of Sheffield and for the past two days the reception of the BBC National Ensemble has been virtually non existent indoors,” wrote user Darcy72.

“All other stations are fine and the BBC reception page says no reported problems with the three local transmitters – Sheffield, Clifton and Emley Moor.”

Digital radio transmitters use GPS satellites to synchronise their broadcasts, which must be sent all at the same frequencies. The transmitters use the GPS signals for timing.

But the US Air Force said in a statement that when the satellite was removed from service, the time signal was thrown off by 13 milliseconds, causing the problems.

Finland’s Metsahovi Radio Observatory first picked up the timing discrepancy.

“On 26 January at 12:49 a.m. MST, the 2nd Space Operations Squadron at the 50th Space Wing, Schriever Air Force Base, Colo., verified users were experiencing GPS timing issues,” said the US Air Force.

“Further investigation revealed an issue in the Global Positioning System ground software which only affected the time on legacy L-band signals. This change occurred when the oldest vehicle, SVN 23, was removed from the constellation.

“While the core navigation systems were working normally, the coordinated universal time timing signal was off by 13 microseconds which exceeded the design specifications.”

The satellite SVN 23 was launched from Cape Canaveral on November 26 1990, and was the oldest GPS satellite still in operation up until its decommissioning date of January 26.

“Operator procedures were modified to preclude a repeat of this issue until the ground system software is corrected, and the 50th Space Wing will conduct an Operational Review Board to review procedures and impacts on users.”

Take our cloud quiz here