April 6 is the day when car navigation in many vehicles could give drivers a lot of problems. It turns out that some devices just stopped working. We know why this happened. All by resetting the numbering of weeks, which takes place once every 19 years.


The change in the numbering counter takes place once every 19 years. The latter took place on April 6, 2019. That’s when some car navigators may have caused problems or simply stopped working. This is a weekly week zero reset event (WNRO) in the GPS satellite system.

The Ministry of Digitization, citing US Naval Observatory data, reported that the problem with GPS navigation will not apply to GPS receivers that were manufactured after 2010. The older ones may stop working and will need to be updated accordingly.

Numbering weeks

Resetting the numbering of weeks can be compared to resetting the counter when the number reaches 99 999. Then the number 0 will appear on the counter. The GPS device will display information about the so-called Zero week. It is counted from January 6, 1980. In practice, this means that GPS will tell us that it is 1980. Do we go back in time?

The change of the week numbering counter takes place once every 19 years. This is related to the data being written, where a 10-bit number was used. This means that the week counter is a range of numbers from 0 to 1023.

The Ministry of Digitalization also reminded that it is uncertain how exactly car makers and GPS devices coped with these changes. The producers themselves, such as Garmin and TomTom, kept their users up to date with updates. However, most car manufacturers point out that changing the numbering of weeks will not have a negative impact on the use of navigation mounted in cars.

Source: auto-swiat.pl