older gps - week counter rollover Apr 6 '19

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https://www.theregister.co.uk/2019/02/12/current_gps_epoch_ends/

Older satnavs and such devices won't be able to use America's Global Positioning System properly after April 6 unless they've been suitably updated or designed to handle a looming epoch rollover.

GPS signals from satellites include a timestamp, needed in part to calculate one's location, that stores the week number using ten binary bits. That means the week number can have 210 or 1,024 integer values, counting from zero to 1,023 in this case. Every 1,024 weeks, or roughly every 20 years, the counter rolls over from 1,023 to zero.

The first Saturday in April will mark the end of the 1,024th week, after which the counter will spill over from 1,023 to zero. The last time the week number overflowed like this was in 1999, nearly two decades on from the first epoch in January 1980.

You can see where this is going. If devices in use today are not designed or patched to handle this latest rollover, they will revert to an earlier year after that 1,024th week in April, causing attempts to calculate position to potentially fail. System and navigation data could even be corrupted, we're warned.
 
I still have some hardware that suffered from the first rollover around 2001. A non-rollover aware receiver will still provide correct position reports and the hour and minute of the day. The date and year will be wrong. Internally, GPS does not need to know the date and year in order to function. Output of this data was always considered only a convenience to users and not to be used for navigation.

Since the first rollover, additional bits have been placed in the GPS data stream to extend the date range. Any modern receiver (made after the new standard) should be programmed to examine these bits and handle the "rollover" properly.

Another thing about GPS time is that it does not include "leap seconds" that are added to official time once or twice a year to real time to keep it in sync with the orbit of the Earth around the Sun. That also is handled in software as a convenience to users.
 
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Wonder what models will be affected?

I have 3 standalone GPS units I use on occasion (Garmin 260, 260w, 255w), all from 2008/2009.
I know I have done at least firmware upgrade at some point in time on all of them.
Not a real concern for me so long as they power on, I dont care if it thinks it is 2002 so long as the gps part still works.

My wife's new Hyundai has an in-dash GPS, and has an update from last year, so should be good.
 
As I said...as long as you can choose UTC it will be fine....

[Linked Image]
 
So far one report from one user of Garmin GPS12 that his gps is stuck in year 1999......some Carminat GPS systems in Renault vehicles needs to be updated....latest FW will resolve that "Y2K GPS glitch"...

And some Boeing 787`s in China are grounded until the update...
[Linked Image]
 
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Yeah, we've been checking for potential problems in our systems for months. Since I didn't get called over the weekend, I presume it all worked OK.

Leap seconds are still a pain in the butt, though.
 
https://support.garmin.com/en-US/?faq=zWQY6Z2kFiAuY9kDnDBgZ6

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For GPS devices that are affected, after the rollover occurs, an incorrect date and time will be displayed. This incorrect time will also be used to timestamp track logs, compute sunrise and sunset, and other functions that rely upon the correct date and time. However, the positioning accuracy will not be affected. The device will continue to deliver the same positioning performance as before the rollover.
 
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