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  2. 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 ...

  3. 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 ...

  4. Error analysis for the Global Positioning System - Wikipedia

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

    If a fast time to first fix (TTFF) is needed, it is possible to upload a valid ephemeris to a receiver, and in addition to setting the time, a position fix can be obtained in under ten seconds. 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.

  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. Time to first fix - Wikipedia

    en.wikipedia.org/wiki/Time_to_first_fix

    The receiver has estimates of the current time within 20 seconds, the current position within 100 kilometers, its velocity within 25 m/s, and it has valid almanac data. 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 ...

  7. American Ephemeris and Nautical Almanac - Wikipedia

    en.wikipedia.org/wiki/American_Ephemeris_and...

    The American Ephemeris and Nautical Almanac was published for the years 1855 to 1980, containing information necessary for astronomers, surveyors, and navigators. It was based on the original British publication, The Nautical Almanac and Astronomical Ephemeris, with which it merged to form The Astronomical Almanac, published from the year 1981 to the present.

  8. SPICE (observation geometry system) - Wikipedia

    en.wikipedia.org/wiki/SPICE_(observation...

    SPICE data files are usually referred to as "kernels." These files provide information such as spacecraft trajectory and orientation; target body ephemeris, size and shape; instrument field-of-view size, shape and orientation; specifications for reference frames; and tabulations of time system conversion coefficients. [3]

  9. Astronomical Almanac - Wikipedia

    en.wikipedia.org/wiki/Astronomical_Almanac

    The Astronomical Almanac [1] is an almanac published by the United Kingdom Hydrographic Office; it also includes data supplied by many scientists from around the world.On page vii, the listed major contributors to its various Sections are: H.M Nautical Almanac Office, United Kingdom Hydrographic Office; the Nautical Almanac Office, United States Naval Observatory; the Jet Propulsion Laboratory ...