The world didn't end: GPS devices save the date, fend off Y2K hysteria

Glitch expected to affect older GPS systems or ones that hadn't been updated doesn't show up.

It was the Y2K bug’s little brother, with about the same impact: the world as we know it didn’t end.

Thanks to a quirk in how Global Positioning Systems keep track of time, some devices were due to have their calendars reset at 7:59 p.m. EDT on Saturday. The change echoed the mostly overhyped hysteria about global computer systems that gripped the world when the calendar was about to tick over from 1999 to 2000. Societal collapse was again avoided.

The glitch was only expected to affect older GPS systems or ones that hadn’t been updated. The U.S. Department of Homeland Security did signal it wasn’t expecting wide-scale disruptions, but it still warned that utilities, financial systems, airlines and telecommunication systems could be affected by the problem.

“Anyone who relies on precision timing to do business should be aware there could be some impacts,” Bob Kolasky, director of the department’s Cybersecurity and Infrastructure Security Agency’s National Risk Management Center, said before the reset. “It’s a pretty broad flaw.”

GPS time: 1024 weeks

The issue was caused by the “1024 week number rollover.” GPS systems keep track of time by counting weeks, but only have enough data to keep track of 1,024 of them before they reset to Jan. 6, 1980, when the system first went online.

The last time that happened was in August 1999 when GPS was used a lot less for everything from flying planes to mapping one’s jogging routes to locating lost pets.

Ahead of the big day, navigation technology manufacturer TomTom NV told users on its website that there was “no need to worry” if you frequently update your device, but said those who don’t may find “navigation impossible” among other problems.

Little worry

Garmin LTD said its testing had shown the “vast majority” of its GPS devices would handle the rollover without issue, and those that were affected would see an incorrect date and time displayed but “the positioning accuracy will not be affected.”

But other industries that rely on precise time braced ahead of time for a possible impact.

Edward Powers, the GPS Operations Division Chief for the U.S. Naval Observatory, warned in a 2017 presentation that the rollover could lead to corrupted data and system failures, with problems occurring beyond April 6.

“A nanosecond error in GPS Time can equate to one foot of position (ranging) error,” the Cybersecurity and Infrastructure Security Agency, which is part of DHS, said in a memo warning about the problem.