Navigation Center Website Top Header Banner
Home | LNMs | BNMs | Nav Rules | AIS Data Requests | AIS Overview | GPS Constellation | GPS Testing | GPS Almanacs | USCG Int'l Ice Patrol | Contact Us | Search
Maritime Safety Data
Nav Systems and Services
Maritime Safety Information
Report a Problem

Print friendly version  

Precise Ephemeris Information

The U.S. Department of Transportation's Civil GPS Service has designated NOAA to be the federal agency responsible for providing accurate and timely Global Positioning System (GPS) satellite ephemerides ("orbits") to the general public. The GPS precise orbits are derived using 24 hour data segments from the global GPS network coordinated by the International Geodynamics GPS Service (IGS). the reference frame used in the computation is the International Earth Rotation Service Terrestrial Reference Frame (ITRF). In addition, an informational summary file is provided to document the computation and to convey relevant information about the observed satellites, such as maneuvers or maintenance. The NGS Precise orbits generally are available seven days after the date of observation.

The following link will direct you to the National Geodetic Survey website, where you can download the latest GPS Precise Ephemeris data and much more.