As war in the Gulf continues, the Maritime Safety Authority (MSA) is quick to reassure users of GPS (global positioning satellite) location devices that the US military will not switch the network off.
When the US Department of Defense (DoD) began launching GPS satellites in the 1980s, it provided two classes of service: signals with an accuracy to 10m or 20m for military users and a degraded signal available to civilian users accurate to 100m.
In May 2000 the US government announced it would allow commercial users to receive the more accurate signal from the GPS system as long as it could be degraded in times of international trouble.
Engineers at GPS device specialist Navman in New Zealand said it is possible for the US DoD to switch off the system entirely. But a spokeswoman for the MSA said any move to degrade the service would first be announced by the US.
Ray Parker, spokesman for the National Rescue Co-ordination Centre in New Zealand, believes at most the US would limit the accuracy of the system for non-military users.