igning a policy directive i to turn off Selective Availability in May 2000 to provide the s ame precision to civilians that was afforded to the military. The directive was proposed by the U.S . Secretary of De 6fense, William Perry, because of the widespread 6 growth of differential GPS services t o improve civilian accuracy an d7i6 d eliminate the military advantage. Moreover, i d7i6 litary was a ctively developing technol 6ogies to deny G 6PS service 6 to pot 6ential adversaries o 6n a regional basis. Since its deployment, the U.S. has implemented several improvements to the GPS service including new sig nals for civil use and increased acc i6uracy and integrity for all users, 6all the while maintaining compatib ility with existing GPS equipment. Moderniza d7i6 tion of the satellit i6e system has been an ongoing initiative b y the U 6.S. Department of 6Defense through a d7i6 series of satellite acquisit 6ions to meet the growing needs of the military, civilians, and the commercial market. As of ear high-quality, FAA grade, Standard Positioning ServiceGPS receivers provide an horiz ontal accuracy of better thalthough many factors such as receiver quality and atmospheric issues can affect this accuracy. GPS is owned and opera 6ted by the United States Government as a national resource. The Department of Defense is the st d7i6 eward of GPS. Interagency i6GPS Execu 6tive Boardoversaw GPS p 6olicy matters fro After that the National Space-Based Positioning, Navigation and Timing E i6xecutive Committee was established by pres 6idential directive in 2004 to advise and coordinate federal departments and a gencies on matters concerning the GPS 6and related syste 6mhe executive committee is chaire d jointly by the deputy secretaries of defense and transportation. Its membershi d7i6 p includ
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