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Accurate GPS access available to civilians in US, May 2, 2000

-May 02, 2014

Eighteen years after the United States Air Force conducted developmental flight tests of two prototype GPS (Global Positioning System) receivers using ground-based pseudo-satellites, President Bill Clinton ordered an end to Selective Availability for civilians on May 2, 2000.

Selective Availability intentionally limited precision of GPS receivers for non-military use. The switch was flipped at midnight on May 1, 2000, making May 2, the first day non-military systems would have improved precision from 330 to 66 feet available.

Prior to this, the highest quality signal was reserved for military for defense reasons. The 2000 move came after an executive order was signed in 1996 to turn off Selective Availability. The order was proposed by US Secretary of Defense William Perry because of the widespread growth of differential GPS services, to improve civilian accuracy, and to eliminate the US military advantage. The military was also actively developing technologies to deny GPS service to potential adversaries on a regional basis.

GPS remains owned and operated by the United States government as a national resource. The Department of Defense is required to maintain a Standard Positioning Service and develop measures to prevent hostile use of GPS without unduly disrupting or degrading civilian uses.

The US Air Force currently manages the constellation of GPS satellites and is required to keep at least 24 satellites available 95% of the time.

The latest satellite to be launched from Cape Canaveral was GPS IIF-5 on February 21, 2014, and there are plans to launch seven more GPS IIFs.

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For more moments in tech history, see this blog. EDN strives to be historically accurate with these postings. Should you see an error, please notify us.

Editor's note: This article was originally posted on May 2, 2013 and edited on May 2, 2014.

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