Will GPS give us another Y2K situation on 6 April?

I remember some of the predictions about the Y2K situation. Life as we know it would end and society would be hurled back to the Stone Age. Only bows and arrows would remain and if you wanted lunch you’d have to hunt and kill it first.

In the event there was barely a grumble from our computer systems. Most IT departments had fixed the problem long before December 31st 1999.

The 6th April 2019 is going to be another Y2K situation, this time relating to GPS and satellites.

Legacy GPS systems calculate the date and time by storing a week number and then the number of seconds into that week. The week number is only stored in 10-bit field, making for a maximum of 1024 weeks, which is approximately 19.6 years.

GPS time started on 6 January 1980, so we’ve already passed one GPS epoch on 21st August 1999. I don’t remember reading too much about problems with GPS back then, although it’s fair to say GPS was much less prevalent in 1999 than it is now.

So the counter was reset in 1999 and the next reset is due on 6 April this year (2019).

Will this Y2K-type situation throw us back to an era of woolly mammoths?

I doubt it. I would imagine the ground station IT people have it in hand. Furthermore, newer satellite systems use a 13-bit field for the week, giving us 8192 weeks or 157.5 years.

We should be safe, although the US Naval Observatory has seen fit to issue a warning about it.

These words may come back to haunt me but I’d like to bet we barely notice. Nevertheless, I’d avoid taking a flight that day.