President Clinton ordered the cancellation of the Selective Availability mode on GPS satellites as of midnight on 1 May. This system, which amounted to intentionally degrading the GPS signal so that non-military users lack the precision of the US military users. Accuracy for civilian users will improve from "within 100 meters" to "within 12 meters" more than 95% of the time and within 6 meters about half of the time. While critics of the President decried this move as "giving away US security" the move actually means little harm to the US. In the event of a war, the Selective Availability mode would be turned back on (at least for the affected theaters) to deny the enemy the chance to use such US GPS signals for their own precision-guided weapons. The change does not benefit aircraft or cruise missiles, as these (due to their propensity for vertical movement) need integrated signals for accurate navigation.--Stephen V Cole