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  2. JPL Horizons On-Line Ephemeris System - Wikipedia

    en.wikipedia.org/wiki/JPL_Horizons_On-Line...

    JPL Horizons On-Line Ephemeris System provides access to key Solar System data and flexible production of highly accurate ephemerides for Solar System objects. Osculating elements at a given epoch (such as produced by the JPL Small-Body Database ) are always an approximation to an object's orbit (i.e. an unperturbed conic orbit or a " two-body ...

  3. GPS signals - Wikipedia

    en.wikipedia.org/wiki/GPS_signals

    Each subframe has the GPS time in 6-second increments. Subframe 1 contains the GPS date (week number), satellite clock correction information, satellite status and satellite health. Subframes 2 and 3 together contain the transmitting satellite's ephemeris data. Subframes 4 and 5 contain page 1 through 25 of the 25-page almanac. The almanac is ...

  4. 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 position ...

  5. Error analysis for the Global Positioning System - Wikipedia

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

    It is feasible to put such ephemeris data on the web so it can be loaded into mobile GPS devices. [6] See also Assisted GPS. The satellites' atomic clocks experience noise and clock drift errors. The navigation message contains corrections for these errors and estimates of the accuracy of the atomic clock.

  6. 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.

  7. XEphem - Wikipedia

    en.wikipedia.org/wiki/XEphem

    XEphem is a client for Internet data sources such as the Digitized Sky Survey, Solar and Heliospheric Observatory, AAVSO light curves, and global temperature and cloud coverage. Through the Instrument Neutral Distributed Interface , XEphem can control some models of amateur telescopes, such as by Meade , Celestron , and Vixen , and auxiliary ...

  8. 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 ...

  9. Argos (satellite system) - Wikipedia

    en.wikipedia.org/wiki/Argos_(satellite_system)

    However, due to ground-based alarm system interference issues in the United States, [8] the downlink was disabled on the NOAA-19 satellite. [9] Other newer satellites still transmit on this frequency. The downlink contains date and time, Argos System satellite ephemeris data, and the downlink portion of the two-way communication link.