#Gps week number rollover how to#

The first GPS satellites went live on 6 January 1980, meaning that the first epoch of GPS time lasted until 21 August 1999. GPS used a 10 bit field to encode the week number in each GPS time message, which means that a maximum of 1,024 weeks (19.7 years), could be handled. Each of these periods is known in GPS terms as an “epoch”.Īt the end of each epoch of 1,024 weeks, the receiver resets the week number to zero and starts counting again. The Week Rollover Problem is a known issue caused by the way that GPS used to handle the week element of the data that forms an essential part of the navigation signal. The good news is, it’s easy to check now whether your receivers are affected or not, giving plenty of time to implement a solution.īut first, let’s look at what’s causing the problem. Similar – but different – to the Millennium BugĪs we’ll see, it’s not quite the Millennium Bug for GPS receivers, but it does share some similarities. (To give just one example, GPS trackers employed in a fleet management system to track deliveries could cause system errors or even a crash if they suddenly start to output location data timestamped with a date 20 years in the past.) But it will create week, month and year timestamps that are wildly wrong, which could seriously impact any systems and applications that rely on GPS data at that level. This won’t affect the receiver’s ability to navigate and/or calculate precise time from the day level down to the microsecond level. The data they output may suddenly jump backwards in time, putting timestamps on your timing and navigation data that are nearly 20 years out of date. If they are, you may find your receivers start to behave strangely on – or more likely at some point after – 6 April 2019. If your vehicles or equipment rely on GPS receivers, now is the time to check if they’re affected by the GPS Week Number Rollover issue.

#Gps week number rollover how to#

Here’s what that means and how to check if a receiver is vulnerable.

Some GPS receivers may malfunction on or after 6 April 2019 due to the GPS Week Rollover.