Everything you need to know about GPS Week Number Rollover

Does your organization rely on GPS? If so, you might need to prepare for GPS Week Number Rollover. Here’s what you need to know.

GPS-reliant technology is hugely important to numerous businesses across the globe. As a precaution, those organizations should familiarize themselves with the upcoming GPS Week Number Rollover (WNRO). Below, we’ll run you through everything you need to know.

What is GPS Week Number Rollover (WNRO)?

WNRO is an event with the potential to impact GPS receivers worldwide. Many businesses offer services that rely on GPS, therefore, it’s important to understand how the event could impact the normally smooth functioning of GPS.

What exactly is happening?

A GPS signal contains a time element tracked by weeks. This number is encoded as a 10-bit field in each message. A maximum of 1,024 weeks can go by before GPS receivers need to reset the week number and start counting again from zero. This period is called an epoch, and we’re about to rollover from one epoch to the next.

When is GPS Week Number Rollover?

Our current epoch started on August 1, 1999 and is due to end on April 6, 2019, which is when the rollover takes place.

This sounds familiar. Hasn’t it happened before?

Yes. In August 1999, when we moved into our current epoch. That was nearly 20 years after the launch of the first GPS satellite. Nothing major happened then, but technology has since become increasingly dependent on GPS.

What could potentially happen?

It’s possible the rollover could create some GPS or timing errors.

Will this only relate older GPS systems?

No. All GPS systems have the potential to be affected by WNRO.

Are all products or services from HERE dependent on GPS?

No, not all. However, GPS is often used as a default system timing service (for example, internet time uses GPS). As such, there’s a touch of unpredictability on whether some internet-related services could be impacted.

What can we do to prepare?

Organizations such as Homeland Security in the U.S. and the Australian Cyber Security Centre recommend that critical infrastructure, owners and operators consider a handful of actions. These include ensuring device firmware is up to date and being mindful of the possible impact if receivers stop operating, or report the wrong GPS or Universal Time Coordinated (UTC) information. Additionally, they suggest contacting the GPS receiver manufacturer to ensure the device will not be affected.

Will products or services from HERE be impacted?

The good news is that we don’t anticipate any major issues. It’s likely that service will continue as normal. However, issues might arise that are beyond our control and, as such, we’ve prepared for any surprises and will conduct additional status monitoring during the rollover period.

Topics: Editor's Picks, Science of Maps, GPS, Required Reading

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