On-Line Resources for
Land Surveying and Geomatics
are welcome and appreciated.
Last Revised: 18 August 2010 .....
links updated and verified: 29 March 1998
Satellite Navigation Systems
Selective Availability (SA) switched off!
The U.S. Naval Observatory provides
current NAVSTAR status information
in a number of different ways.
You may obtain precise ephemeris and other data by
direct dial the U.S. Coast Guard BBS at
703-313-5910, or telnet through
From the main menu (/go main) type UDD54
the U.S. Coast Guard's new
Navigation Information Service Internet
the U.S. Space Command's
GPS Support Center
GPS Explained by the FAA
Precise Ephemerides are also available via
ftp from NGS.
Status information is available from
status summaries are available from the
Austrailian Surveying and Land Information Group (AUSLIG) site;
Almanac Data is available from
MIT and from
the US National Telecommunications and Information Adminstration, Office of Spectrum Management,
maintains a site covering Issues for WRC-99
NGS works with the
United States Coast Guard to implement their
DGPS Project, a system of
Continuously Operating Reference Stations (CORS)).
link:2003 CORS User Forum
other Base Station data publically available:
Radio Broadcast Correction Services for DGPS
the Institute of Navigation
the Navtech GPS Store
Vendors on line: