Global GPS Time Anomaly on Tue, Jan 26th

On Tuesday, Jan 26th 2016 around 2:00 UTC multiple GPS satellites started broadcasting wrong time information that affected high accuracy GPS time sync receivers in many regions of the world, including Europe, North America and Asia.

Update: The US Air Force published the official press release on their website: USAF Official Press Release - GPS Gound System Anomaly

Meinberg detected sporadic time jumps of ~13 microseconds on all GPS receivers in their production and R&D facility in Bad Pyrmont, Germany. This started around 02:00 UTC (3:00AM CET). The GPS receivers jumped several times back and forth over hours, stopping and returning to normal operation around 12:00 UTC (1:00PM CET).

Meinberg support received several hundred reports of similiar behavior from customers in Asia, the US, Europe and other regions over the course of the whole day.

An in-depth investigation by Meinberg GPS Experts showed that not only Meinberg devices were affected by this problem, suggesting that this had been caused by a problem with the GPS satellites. The investigation revealed that a number of GPS satellites, while declaring themselves "healthy", broadcast a wrong UTC correction parameter that is an important part of the overall time calculation formula used by GPS timing receivers. Meinberg immediately contacted USCG NAVCEN, the point of contact for civil GPS users, provided technical details and informed them about their findings. USCG NAVCEN confirmed that there had been problem reports from other GPS users and stated that the US Air Force as the main operator of the GPS NAVSTAR system identified the problem and was working on resolving it.

Several websites started to publish information about the incident, starting on Tuesday shortly after 16:00 local time with the Finnish Aalto University, later the Norwegian Security Website AldriMer.no published an article about the incident. The GPS related news website GPSworld.com mentioned in a short article that the US Coast Guard had informed them about user reports regarding a GPS problem, asking everyone to use the USCG contact form to report GPS issues.

On late Wednesday evening AldriMer updated their website with a statement they had received from USCG/USAF, confirming the problems and stating that this had been caused by a software bug. An official US Air Force press release was sent to subscribers of the CGSIC newsletter on Wednesday, explaining that a bug in the GPS ground software led to the wrong UTC correction value being broadcast. The Air Force indicated that this bug started to cause problems when the satellite SVN 23 was removed from the constellation. This scheduled decommissioning of this oldest GPS satellite has been pre-announced using the usual procedures and, according to the 2nd Space Operations Squadron at the 50th Space Wing, Schriever Air Force Base, Colorado, went according to plan. Unfortunately it seemed to trigger the GPS ground segment software bug and the Air Force confirmed that operator procedures have been modified to avoid to preclude a repeat of this issue until the software has been fixed.

Meinberg GPS experts continue to investigate on the incident and work on implementing GPS firmware improvements to reduce or avoid the impact of this kind of technical issues with the GPS system. You can access the technical report in its current state here: Meinberg Technical Report on the Jan 26th GPS Anomaly

At the time of the release of this news article, no press release or any other form of official statement has been published on the websites of the US Air Force or US Coast Guard. We will update this article as soon as this changes.

Meinberg users still experiencing problems with their devices are requested to inform their Meinberg technical support contact.