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This almanac is transmitted repeatedly over 12.5 minutes. Almanac data can be received from any of the GPS satellites and is considered valid for up to 180 days. Warm or normal 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.
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]
Variability in solar radiation pressure [5] has an indirect effect on GPS accuracy due to its effect on ephemeris errors. 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.
The offset 32.184 seconds was the 1976 estimate of the difference between Ephemeris Time (ET) and TAI, "to provide continuity with the current values and practice in the use of Ephemeris Time". [ 9 ] TAI is never revised once published and TT(TAI) has small errors relative to TT(BIPM), [ 6 ] on the order of 10-50 microseconds.
Ephemeris time based on the standard adopted in 1952 was introduced into the Astronomical Ephemeris (UK) and the American Ephemeris and Nautical Almanac, replacing UT in the main ephemerides in the issues for 1960 and after. [30] (But the ephemerides in the Nautical Almanac, by then a separate publication for the use of navigators, continued to ...
The Farmers' Almanac. First printed in 1818 by David Young. Predicts next year's weather for seven U.S. and five Canadian climatological regions. Predicts what will be the best days to fish, wean ...
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 ...
Learn how to download and install or uninstall the Desktop Gold software and if your computer meets the system requirements.