http://www.gpsworld.com/resources/almanac.htm
http://tycho.usno.navy.mil/gps.html
By Time Service Dept., U.S. Naval Observatory, Washington
D.C.
http://www.navcen.uscg.gov/gps
http://www.gpsy.com/gpsinfo
By Karen Nakamura
On October 3rd, 1996
http://www.trimble.com
By Trimble Navigation Limited