Tag: L-band

It happened in the blink of an eye. Less than a blink. Far less, actually. Slightly more than one one-thousandth of an eye blink, according to calculations. In that amount of time, one of your eyelashes traverses 10 micrometers on its journey toward your lower eyelid.

And yet it was long enough to throw computers and communications systems around the world out of whack, generate thousands of alarms, and pull engineers from their beds at 2 a.m.

One occurrence might have been enough to do all that. I’m not sure. But it kept happening over and over again. Thus the alarms, the out-of-whackness, the sleep deprivation. At least it did not generate massive financial trading sell-offs, blow holes in national security, or shut down Facebook, Instagram and Snapchat. For that, we may be thankful.

But it might have.

“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. 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 issue was resolved at 6:10 a.m. MST, however global users may have experienced GPS timing issues for several hours.” (This excerpt from an U.S. Air Force communiqué appears in a brief news account.)

“The Joint Space Operations Center at Vandenberg AFB has not received any reports of issues with GPS-aided munitions, and has determined that the timing error is not attributable to any type of outside interference such as jamming or spoofing. Operator procedures were modified to preclude a repeat of this issue until the ground system software is corrected.”

Companies and their time-servers around the world were subsequently hit by up to 12 hours of system warnings after 15 GPS satellites broadcast the wrong time, according to Chronos, a UK-based time-monitoring firm.

Telecommunications companies constitute only a small part of industry users who rely on the highly precise accuracy of time measurements — supplied by GPS — to control data flow through their networks. Global financial networks and trading markets similarly depend on GPS, as do electrical power grids and many other sectors of critical national infrastructure. These companies and networks invest significantly in highly sophisticated equipment to monitor said timing accuracy as conveyed by GPS signals. Because billions, make that trillions — or actually even more — are riding on it.

A week after the eye blinks, Chronos Technology released a white paper describing the ensuing fallout for its clients, who are timing equipment users in more than 50 countries around the world. Table 1 from the white paper reports the experience of a few during the event. One company registered nearly 2,500 alarms from its timing equipment during the outage.

At one point during the crisis, according to the white paper, “it appeared that the GPS error had cleared and the Chronos SSP Manager was able to force the units out of holdover. However the scale of the problem escalated as these sites went back into holdover along with dozens of other sites suffering GPS-based timing issues. It was apparent at this point that there was something amiss with the GPS constellation itself.”

Later on, the report states, “This event linked to SVN23 has been one of the most significant service affecting issues for GPS timing users and sits alongside the April 1st 2014 GLONASS outage in scale — however its impact on global timing services is much more extreme.”

Ominously, “Chronos is aware of other more catastrophic impacts to networks and non-telecom applications which were not under supply and support contracts.”

As Loran Is Our Savior. At least one timing-reliant company was not disturbed by the problems, because it was testing an alternative timing service provided by enhanced Loran (eLoran) signals.

Unfortunately for them — and for the rest of us — eLoran has a very uncertain future. In fact, they were lucky to have an eLoran signal at all on January 26, because it was supposed to have been turned off on December 31. Somebody must have forgotten to tell the operators at the Anthorn giant antenna field in Cumbria to go home.

France, Norway, and the United Kingdom, three countries that had been keeping eLoran alive, officially abandoned the effort at the end of last year, reportedly because of lack of leadership from the United States.

The U.S. government decommissioned all its Loran stations a few years ago, even going to the extent of blowing some of them up (perhaps to prevent them from falling into the hands of subversives). Despite a recent reinvigorated interest in enhanced Loran technology, it may be too little, too late.

Whoa, Nellie. The first recorded use of the term “back-up technology” occurred in 1892, when farmers were urged not to prematurely abandon their mules in favor of John Froehlich’s new gasoline tractor.

That admonition, however prudent, has since passed from view. But the concept remains sound. It has surfaced many, many times in GPS World magazine. Certainly not the first incidence, but the farthest back that I can retrieve via search on our website, came in 2007 from Defense contributing editor Don Jewell. “Why do we need a backup? Here is a classic case in point.” He describes a Joint Navigation Conference briefing on a surprise jamming incident that had occurred in January of that year.

In 2009, we reported on an Independent Assessment Team (IAT) report that “unanimously recommends that the U.S. government complete the eLoran upgrade and commit to eLoran as the national backup to GPS for 20 years.” The report was written in 2007, but quashed by the Department of Transportation and Department of Homeland Security (DHS) Executive Committees that commissioned it. Its public release came only after an extensive Freedom Of Information Act (FOIA) battle.

The U.S. government proceeded, despite its paid experts’ recommendations, to blow up those old Loran stations. The current renewed interest and the Wildwood experiment are worthy — more than worthy. Can they prevail? Can they survive blind reliance on a single string of vulnerable technology?

Indubitably, the critical role of GPS back-up was advanced prior to 2007, I just can’t document it this morning by deadline. For the sake of argument, let’s take April 12, 2007, as our start.

We are now 3,229 days out. That’s 77,496 hours, or nearly 279 million seconds. Correct me if wrong, but that appears to make 21.5 million-million times the length of January’s GPS timing error. Surely sufficient to blink a few times, scratch one’s head, and wonder.

Could there be a better way?