Devices relying on GPS technology may go haywire this weekend, scientists have warned, reports the Daily Mail.
Motorists, sailors, and pilots using GPS technology could all be affected on Saturday at 1am GMT - with the risk greatest with older models of satellite navigation (satnavs) devices.
But GPS is also used in many other applications, including the electricity grid, which could also be hit, experts warned.
The warning has been issued by the National Physical Laboratory in the UK as well as satnav makers TomTom and Garmin.
The problem is that the timing system on many older models is due to reset - or “rollover” - this weekend.
The NPL said the effects of the “GPS rollover” were “truly unpredictable.”
But it could mean the time and date - as well as the estimated time of arrival at destination - going wrong, with a software update needed to fix it.
Other impacts could be on financial traders who use GPS to record trades, and ports which use GPS information for the loading of ships.
The problem arises because when GPS was invented in 1980, the date and time was represented by a counter that could only count forward a maximum of 1024 weeks, or about 19.7 years.
After 1024 weeks, this counter “rolls over” to zero and this can potentially cause a satnav or other system to shut down.
The first rollover occurred in August 1999 - when comparatively few GPS devices were in operation.
But the second rollover will occur at 1am GMT on April 6, 2019.
The NPL said any GPS receivers not programmed to reset correctly on Sunday may jump to an incorrect date and time, potentially affecting service.
How does GPS work?
The Global Positioning System (GPS) is a network of about 30 satellites orbiting the Earth at an altitude of 20,000km.
The system can pinpoint your location anywhere on Earth.
The system was originally developed by the US government for military navigation but now anyone with a GPS device, be it a SatNav, mobile phone or handheld GPS unit, can receive the radio signals that the satellites broadcast.
Wherever one is on the planet, at least four GPS satellites are “visible” at any time.
