The global positioning system (GPS) faces its toughest test this week when it reaches the end of its date cycle and resets itself to zero.
GPS, which works on a weekly cycle and will reach its maximum, 1024, on August 23 in New Zealand, was developed as a location-tracking tool for the US military. The US Department of Defence deployed and maintains the dozens of GPS satellites stationed in geosynchronous orbit above Earth. Signals from these satellites are used by GPS receivers to calculate the latitude, longitude and altitude of the receiver location in real time.
In New Zealand GPS use is less advanced than in the US or Europe. Boaties are probably the largest single user group, and they have an added advantage over other users of GPS systems - salt water.
Boat-based GPS systems rust, making users upgrade on a regular basis, meaning most of New Zealand's boaties have relatively new compliant units.
"We've assessed all our products for both [rollover] and Y2K in one go," says a spokesman for Trimble Navigation, a major supplier of GPS equipment. "We've gone through all the receivers we've ever produced and our Web site lists them for compliance." The site (www.trimble.com) lists only five receivers that are completely non-compliant, and Brown believes only one of those models was brought into New Zealand. "I don't know of any that are still operational."
The local airline industry hasn't really embraced GPS as a part of its navigation system - neither Air New Zealand or Ansett New Zealand use GPS units in their aircraft.
Banking in New Zealand is also yet to move over to GPS. ASB Bank's IS manager, Garry Fissenden, says he doesn't know of any bank in New Zealand using GPS to time transactions, although he has heard of banks doing that overseas.
Users of older receivers may need to install a software patch, but newer units should be all right as the industry has been progressively upgrading the software over the last few years. The user base has increased to include commercial and recreational users worldwide.
GPS use isn't limited to simply allowing users to find out exactly where they are - it's also used to determine the exact timing for a number of different reasons. Clocks need to be synchronised in a number of industries, including banking, power production, as well as in large networks where determining signal lag accurately is important.
The exact time of the rollover is 13 seconds before midnight on Saturday, August 21 GMT.