Your GPS watch will (most likely) continue to work fine tomorrow (April 6th)

There’s been plenty of chatter in recent weeks and months about whether this weekend’s upcoming GPS Week Number Roller (WNRO) will impact various GPS devices. In short, on April 6th, 2019 some older devices could effectively reset their knowledge of date/time, causing things like timestamps, sunrise, sunset, tides, and anything else reliant upon date to be off.

The reasoning comes from how GPS devices first transmitted date and time using a counter that rolled forward a maximum of 1024 weeks, or 19.7 years. Garmin’s site on the issue explains it in the most concise manner I’ve seen to date:

“The GPS system is world renowned for its ability to provide accurate and reliable positioning and timing information worldwide. The GPS satellites transmit to users the date and time accurate to nanoseconds. However, back in 1980, when the GPS system first began to keep track of time, the date and time was represented by a counter that could only count forward to a maximum of 1024 weeks, or about 19.7 years. After 1024 weeks had elapsed, this counter “rolled over” to zero, and GPS time started counting forward again.  This first rollover occurred in August of 1999. The second rollover will occur on April 6, 2019.”

With this date approaching, there’s been plenty of reasons to fear the world is ending – however it’s mostly due to tabloid media playing it up. The norm I suppose. Certainly, there will be some devices that are impacted. Hopefully not ones you’re using for anything important. But I’m not here to talk about those.

Instead, I’m here to talk about fitness and sport devices.

I’ve done a super quick check with the major sport/fitness vendors to validate if any issues are expected. In the case of some companies, like Garmin, they have specific support pages listing some brief tidbits. However, they used terms like ‘vast majority’, which in my experience leaves just enough of a gap to fall through. Sorta like if the recipe says ‘The vast majority of the time the cookies come out fine’, you’ll immediately ask:  And the other times?

So I circled back to Garmin on this, and they confirmed that all fitness/outdoor devices are compliant/compatible. It sounds like the ‘vast majority’ part is in reference to potential non-fitness/sport products they make (remember they make automotive/marine/aviation/etc) devices.

Then, I decided to hit up a few other companies. Here’s the quick and easy list:

Fitbit: All sport/fitness/outdoor devices confirmed compatible (Surge/Ionic only units that use GPS). No issues expected.

Garmin: All sport/fitness/outdoor devices confirmed compatible. No issues expected. Company page info here.

Polar: All sport/fitness/outdoor devices confirmed compatible. No issues expected.

Suunto: All sport/fitness/outdoor devices confirmed compatible. No issues expected.

TomTom: All sport/fitness/outdoor devices confirmed compatible. No issues expected. Page info here.

Next, is the one player that I can’t find any info online about. Though I wouldn’t expect any issues – mostly due to how recent their hardware is in the GPS realm.

Apple: I’ve searched high and low, and found nobody talking about Apple devices or concerns.

For the most part, if you have any other newer device – it’s pretty unlikely to be impacted. Devices most likely to be impacted are much older devices, and in the cases of GPS watches in particular, these don’t tend to be around as much (life-span wise) as larger things like car navigation systems.

Companies like Garmin note that even in rare cases where a non-fitness unit wasn’t compatible, it wouldn’t affect positioning (where you are). Just the dates. And, if you have a drone (from DJI), you’re good to go as well.

With that, you can now go and run or ride on Saturday without any worries about being unable to upload your file to Strava afterwards. All shall be well.

Thanks for reading!