GPS Selective Availability: A Retrospective

Raymond Swider, Dave Dickshinski, Roger Robb and John Martel

Abstract:	From the onset, the Global Positioning System (GPS) was designed to provide two levels of performance. The more accurate performance was intended for use by U.S. and allied military forces. A lower accuracy performance level was available for civil users throughout the world. Selective Availability (SA) was a technique employed by the military to introduce deliberate errors into the civil GPS signals. Since it was first activated in 1990, SA was the most controversial aspect of the GPS program. Civil users, who wanted the full accuracy of the system, clamored for discontinuing SA. DoD users insisted SA was essential to preserve a military advantage and prevent an enemy from having the full capability of the system with which to conduct operations against U.S. and friendly forces. In 1996, President Clinton directed that SA be discontinued within 10 years and asked for an annual assessment of progress in discontinuing SA beginning in 2000. This paper discusses the history and chronology of SA, outlines the decision process leading to the discontinuance of SA in May 2000, and provides projections of the performance civil users might expect from GPS in the absence of SA.
Published in:	Proceedings of the IAIN World Congress and the 56th Annual Meeting of The Institute of Navigation (2000) June 26 - 28, 2000 The Catamaran Resort Hotel San Diego, CA
Pages:	319 - 324
Cite this article:	Swider, Raymond, Dickshinski, Dave, Robb, Roger, Martel, John, "GPS Selective Availability: A Retrospective," Proceedings of the IAIN World Congress and the 56th Annual Meeting of The Institute of Navigation (2000), San Diego, CA, June 2000, pp. 319-324.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In