The WNRO could be the 'year 2000 bug' of GPS navigators

A bug similar to the year 2000 problem could affect GPS navigators

The satellite navigation and positioning system, better known by its acronym GPS, from the English Global Positioning System, was developed and launched, among other agencies and companies, by the United States Department of Defense.

In the 1970s it began to be used in practice in tactical and military fields and, decades later, its civil use became popular thanks to the inclusion of this satellite guidance in maritime and air navigation and, subsequently, it became widespread when it was marketed to the general public in mobile devices such as car GPS navigators and, more recently, in smart mobile phones or smartphones.

Its programming was designed so that on 6 April of this year 2019 the GPS Week Number Rollover (WNRO) will arrive, a system reset that occurs every 19 years and which, in this case, may prove critical for the older ones.

What is the WNRO?

On that day the calendar of these devices will reach a maximum of 1,024 weeks of operation, a ceiling that originates from the 10-bit programming used during their creation and development in the 1970s and which was conditioned by the technical limitations of memory; it will then be reset to 0.

By analogy with the automotive world, this is what would happen when a vehicle with a six-digit analogue odometer reached 999,999 km: the next journey would force it to show 000,000 rather than 1,000,000, since it lacks a seventh digit.

This is not the first time the GPS ‘year 2000 bug’ has occurred

The first stage of this ‘calendar’ began on 6 January 1980 and ended on 21 August 1999. The second phase expires on the aforementioned 6 April 2019.

Something similar happened at the end of the twentieth century with the so-called ‘year 2000 bug’, in which computers could suffer system failures when moving from 31 December 1999 to 1 January 1900, in the event that their programming had not, at that time, accounted for the change of millennium for that date.

The consequences of the GPS year 2000 bug

The WNRO may cause a communication failure in the chips receiving the signal from the satellites in orbit, thus losing not only accuracy but also the geolocation capability of the device incorporating them.

Several companies specialising in the marketing of devices that use GPS navigation have already warned which products may be affected and which are not at risk.

For example, TomTom and Garmin have made available to their users lists or checking tools for devices that could suffer failures from 6 April onwards.