GPS Time Rollover Occurrence

GPS Time Rollover Occurrence

The Global Positioning System (GPS) provides accurate timing information to a variety of critical systems including: power grid, communications, financial markets, emergency services, and machines and engines.

Recently, you may have heard recently about an issue in relation to GPS time rollover occurrences impacting GPS devices. The GPS time rollover occurrence relates to the 10-bit field in a GPS time message which must be reset every 1,024 weeks. The first GPS week zero started January 6, 1980. The first instance of the GPS time rollover happened on August 21, 1999. Since then, the clock was reset and has been recounting to the upcoming instance. The rollover to zero will occur on April 7, 2019. Depending on which Product Link device you have installed, this date may also be July 28, 2019, or November 3, 2019.

This issue affects all GPS devices across the globe and is not unique to any Caterpillar machinery. However, we are aware that the GPS time rollover occurrence may impact software in Product Link devices. The rollover is expected to have no impact on machine operation, grade control, or payload functionality.

How We're Working to Resolve This

We are working to update your device firmware to resolve this issue.

  • Impacted cellular devices will be updated over-the-air with new firmware. Devices must be powered on and have uninterrupted cellular coverage for software updates to be applied. Several times per day, perform a power cycle (turn devices off and on) until you receive refreshed telematics data.
  • Impacted satellite devices require a physical over-the-wire software update. Contact your Finning Product Sales and Support Specialist to schedule these updates.

In some cases, a satellite device may need to be replaced. Again, please contact your Finning Product Sales and Support Specialist to determine whether your devices must be replaced, and to schedule a device replacement.

What you will see until the issue is resolved

To avoid inaccurate data being shown in VisionLink applications, all telematics data reported by the impacted devices will be blocked until the software on the device has been updated.

Frequently Asked Questions

When will the next rollover happen?

The next GPS time rollover occurrence will be on April 7,2019.

How will this affect me if my Cat equipment has a Product Link device? 

Product Link devices use GPS satellites to provide both location and time. These devices leverage an internal chip that interprets the date code from the GPS satellite. The satellites provide time data using a counter that represents the number of weeks from a set reference date. When the timestamp is reset to zero as a result of a GPS time rollover, without intervention, the Product Link software may not correctly interpret the timestamp. The effects to you could range from devices sending messages stamped with an incorrect date to not sending a GPS locations or other data at all. Product Link devices might also fail to provide geo-fence alters, appear as non-reporting, show improper asset utilization, or not provide a location.

Which Product Link devices will be affected?

These devices include the PL121 and PL321 units.

What is Caterpillar doing to minimize the impact of this occurence?

We are actively deploying our technicians to physically update or replace hardware for all affected devices.

How do I find out if my equipment is affected?

If you're a Finning customer and you have equipment fitted with a PL121 and PL321 Product Link device, you will receive a communication from your Product Support and Services Representative who will advise you that your Product Link device will need a firmware update or replacement at no cost to you. A member from our team will also contact you personally to arrange a suitable date and time to have the update completed. If you haven’t received an email from us and think you might have a machine that could be impacted by this event, please contact us here.

Is this event similar to Y2K?

Yes, there are similarities to Y2K  -  the GPS time rollover as every 1,024 weeks, the week number (tracked as a 10-bit field in a GPS) must be reset back to zero. This is similar to the clocks rolling over from 1999 to 2000. 

Will this happen again in the future?

GPS is currently undergoing a modernization program to upgrade the signals with new modulation and data message structures. The newer message types (CNAV and MNAV) use 13-bit binary numbers to represent the GPS week number, so it’s expected that the issue won’t occur in the future when more receivers are using the newer GPS signals.

Still have questions?