Never mind the millennium bug, some GPS users can expect problems long before 1 January 2000 - 22 August to be precise.
This is the date for an event known as "GPS Week Number Rollover" and refers to the week number transmitted in the satellite navigation message changing from 1023 to 0.
Some older GPS units may not be able to cope and will need software updates before they can work properly. At best it may take the GPS unit longer to "autolocate" the satellites, at worst it could display the wrong location.
The global positioning system is a satellite-based navigation system consisting of a network of 24 orbiting satellites.
The satellites are constantly moving, making two complete orbits around the Earth in just under 24 hours. Each satellite transmits its name and the time, and from this the GPS unit can see how long the signals took to arrive and triangulates its position.
Steve Gubbins, international sales director for Garmin, (Hall 4, B10) says that he doesn't expect GPS Week Number Rollover to cause many problems.
"Our current range is fully compatible, but some older models may need a software update. Any unit that uses the later 12-channel technology, that is, built within the last two to three years, should be fine."
It is likely to be older, cheaper GPS units that have problems with the rollover - so beware of street traders selling units that appear to be absolute bargains. At least until after 22 August.
Source: Flight Daily News
