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  2. Ephemeris - Wikipedia

    en.wikipedia.org/wiki/Ephemeris

    In astronomy and celestial navigation, an ephemeris (/ ɪ ˈ f ɛ m ər ɪ s /; pl. ephemerides / ˌ ɛ f ə ˈ m ɛr ɪ ˌ d iː z /; from Latin ephemeris ' diary ', from Ancient Greek ἐφημερίς (ephēmerís) ' diary, journal ') [1] [2] [3] is a book with tables that gives the trajectory of naturally occurring astronomical objects and artificial satellites in the sky, i.e., the ...

  3. Error analysis for the Global Positioning System - Wikipedia

    en.wikipedia.org/wiki/Error_analysis_for_the...

    The ionospheric data are transmitted via satellite in Satellite Based Augmentation Systems (SBAS) such as Wide Area Augmentation System (WAAS) (available in North America and Hawaii), EGNOS (Europe and Asia), Multi-functional Satellite Augmentation System (MSAS) (Japan), and GPS Aided Geo Augmented Navigation (GAGAN) (India) which transmits it ...

  4. Time to first fix - Wikipedia

    en.wikipedia.org/wiki/Time_to_first_fix

    It must acquire each satellite signal and obtain that satellite's detailed orbital information, called ephemeris data. Each satellite broadcasts its ephemeris data every 30 seconds with validity of up to 4 hours. Hot or standby The receiver has valid time, position, almanac, and ephemeris data, enabling a rapid acquisition of satellite signals.

  5. Satellite Control Network - Wikipedia

    en.wikipedia.org/wiki/Satellite_Control_Network

    The SCN provides tracking data to help maintain the catalog of space objects and distributes various data such as satellite ephemeris, almanacs, and other information. It was previously known as the Air Force Satellite Control Network (AFSCN) while under Air Force Space Command's 50th Network Operations Group. [1]

  6. GPS signals - Wikipedia

    en.wikipedia.org/wiki/GPS_signals

    The GPS date and time, and the satellite's status. The ephemeris: precise orbital information for the transmitting satellite. The almanac: status and low-resolution orbital information for every satellite. An ephemeris is valid for only four hours, while an almanac is valid–with little dilution of precision–for up to two weeks. [7]

  7. List of satellite pass predictors - Wikipedia

    en.wikipedia.org/wiki/List_of_satellite_pass...

    Satellite AR, by Analytical Graphics augmented reality view of the sky for currently visible satellites only. Includes modes for ISS and bright objects as well as modes which include the thousands of all known satellites. [13] Satellite Passes, supports world map view, augmented reality view, satellite footprint, simulation mode and ...

  8. Satellite navigation - Wikipedia

    en.wikipedia.org/wiki/Satellite_navigation

    Orbital data include a rough almanac for all satellites to aid in finding them, and a precise ephemeris for this satellite. The orbital ephemeris is transmitted in a data message that is superimposed on a code that serves as a timing reference. The satellite uses an atomic clock to maintain synchronization of all the satellites in the ...

  9. United States Space Surveillance Network - Wikipedia

    en.wikipedia.org/wiki/United_States_Space...

    The Satellite Detection and Reconnaissance Defense (the former designation of the NSSS) reached initial operating capability in 1961. The role of the "fence" grew. The system detected space objects from new launches, maneuvers of existing objects, breakups of existing objects, and provided data to users from its catalog of space objects.