33 relations: Coordinated Universal Time, Eastern Hemisphere, Geodetic datum, George Biddell Airy, Global Positioning System, Great circle, International Civil Aviation Organization, International Earth Rotation and Reference Systems Service, International Hydrographic Organization, International Terrestrial Reference System, Latitude, Leap second, Least squares, Lunar Laser Ranging experiment, Meridian circle, Minute and second of arc, North Pole, Plate tectonics, Prime meridian, Prime meridian (Greenwich), Royal Observatory, Greenwich, Satellite laser ranging, Solar time, South Pole, United States Department of Defense, Universal Time, Vertical deflection, Very-long-baseline interferometry, Western Hemisphere, World Geodetic System, 180th meridian, 1st meridian east, 1st meridian west.
The Eastern Hemisphere is a geographical term for the half of Earth which is east of the prime meridian (which crosses Greenwich, London, UK) and west of the antimeridian (which crosses the Pacific Ocean and relatively little land from pole to pole).
A geodetic datum or geodetic system is a coordinate system, and a set of reference points, used to locate places on the Earth (or similar objects).
Sir George Biddell Airy (27 July 18012 January 1892) was an English mathematician and astronomer, Astronomer Royal from 1835 to 1881.
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Air Force.
A great circle, also known as an orthodrome, of a sphere is the intersection of the sphere and a plane that passes through the center point of the sphere.
The International Civil Aviation Organization (ICAO Organisation de l'aviation civile internationale, OACI), is a specialized agency of the United Nations.
The International Earth Rotation and Reference Systems Service (IERS), formerly the International Earth Rotation Service, is the body responsible for maintaining global time and reference frame standards, notably through its Earth Orientation Parameter (EOP) and International Celestial Reference System (ICRS) groups.
The International Hydrographic Organization (IHO) is the inter-governmental organisation representing hydrography.
The International Terrestrial Reference System (ITRS) describes procedures for creating reference frames suitable for use with measurements on or near the Earth's surface.
In geography, latitude is a geographic coordinate that specifies the north–south position of a point on the Earth's surface.
A leap second is a one-second adjustment that is occasionally applied to Coordinated Universal Time (UTC) in order to keep its time of day close to the mean solar time as realized by UT1.
The method of least squares is a standard approach in regression analysis to approximate the solution of overdetermined systems, i.e., sets of equations in which there are more equations than unknowns.
The ongoing Lunar Laser Ranging experiment measures the distance between Earth and the Moon using laser ranging.
The meridian circle is an instrument for timing of the passage of stars across the local meridian, an event known as a culmination, while at the same time measuring their angular distance from the nadir.
A minute of arc, arcminute (arcmin), arc minute, or minute arc is a unit of angular measurement equal to of one degree.
The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is (subject to the caveats explained below) defined as the point in the Northern Hemisphere where the Earth's axis of rotation meets its surface.
Plate tectonics (from the Late Latin tectonicus, from the τεκτονικός "pertaining to building") is a scientific theory describing the large-scale motion of seven large plates and the movements of a larger number of smaller plates of the Earth's lithosphere, since tectonic processes began on Earth between 3 and 3.5 billion years ago.
A prime meridian is a meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°.
A prime meridian, based at the Royal Observatory, Greenwich, in London, England, was established by Sir George Airy in 1851.
The Royal Observatory, Greenwich (ROG; known as the Old Royal Observatory from 1957 to 1998, when the working Royal Greenwich Observatory, RGO, moved from Greenwich to Herstmonceux) is an observatory situated on a hill in Greenwich Park, overlooking the River Thames.
In satellite laser ranging (SLR) a global network of observation stations measures the round trip time of flight of ultrashort pulses of light to satellites equipped with retroreflectors.
Solar time is a calculation of the passage of time based on the position of the Sun in the sky.
The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is one of the two points where the Earth's axis of rotation intersects its surface.
The Department of Defense (DoD, USDOD, or DOD) is an executive branch department of the federal government of the United States charged with coordinating and supervising all agencies and functions of the government concerned directly with national security and the United States Armed Forces.
Universal Time (UT) is a time standard based on Earth's rotation.
The vertical deflection (deflection of the plumb line, astro-geodetic deflection) at a point on the Earth is a measure of how far the direction of the local gravity field has been shifted by local anomalies such as nearby mountains.
Very-long-baseline interferometry (VLBI) is a type of astronomical interferometry used in radio astronomy.
The Western Hemisphere is a geographical term for the half of Earth which lies west of the prime meridian (which crosses Greenwich, London, United Kingdom) and east of the antimeridian.
The World Geodetic System (WGS) is a standard for use in cartography, geodesy, and satellite navigation including GPS.
The 180th meridian or antimeridian is the meridian 180° east or west of the Prime Meridian, with which it forms a great circle dividing the earth into the Western and Eastern Hemispheres.
The meridian 1° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, the Atlantic Ocean, Europe, Africa, the Southern Ocean, and Antarctica to the South Pole.
The meridian 1° west of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, the Atlantic Ocean, Europe, Africa, the Southern Ocean, and Antarctica to the South Pole.