The International Earth Rotation and Reference Systems Service (IERS), formerly the International Earth Rotation Service, is the body responsible for maintaining global

time Time is the continuous progression of existence that occurs in an apparently irreversible process, irreversible succession from the past, through the present, and into the future. It is a component quantity of various measurements used to sequ ...

and reference frame standards, notably through its Earth Orientation Parameter (EOP) and International Celestial Reference System (ICRS) groups.

History

The IERS was established in its present form in 1987 by the

International Astronomical Union The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

and the International Union of Geodesy and Geophysics, replacing the earlier International Polar Motion Service (IPMS) and the Earth rotation section of the Bureau International de l'Heure (BIH). The service began operation on January 1, 1988. Since its inception, the IERS has established new bureaus including the GPS Coordinating Centre in 1990, the DORIS Coordinating Centre in 1994 and the Global Geophysical Fluids Centre in 1998. The organization was formerly known as International Earth Rotation Service until 2003 when it formally changed its name to its present form, in which the organization chose to retain the acronym IERS.

Function

The IERS has various components located in the

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Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

and

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. Among its other functions, the IERS is responsible for announcing leap seconds. The Sub-bureau for Rapid Service and Predictions of Earth Orientation Parameters of the IERS, located at the United States Naval Observatory, monitors the

Earth's rotation Earth's rotation or Earth's spin is the rotation of planet Earth around its own Rotation around a fixed axis, axis, as well as changes in the orientation (geometry), orientation of the rotation axis in space. Earth rotates eastward, in progra ...

. Part of its mission involves the determination of a time scale based on the current rate of the rotation of the Earth. Other services of IERS are at the Paris Observatory. UT1 is the non-uniform time defined based on the Earth's rotation. It defined the IERS Reference Meridian, the International Terrestrial Reference System (ITRS), and subsequent

International Terrestrial Reference Frame The International Terrestrial Reference System (ITRS) describes procedures for creating reference frames suitable for use with measurements on or near the Earth's surface. This is done in much the same way that a physical standard might be descr ...

s (ITRF). Related

coordinate system In geometry, a coordinate system is a system that uses one or more numbers, or coordinates, to uniquely determine and standardize the position of the points or other geometric elements on a manifold such as Euclidean space. The coordinates are ...

s are used by satellite navigation systems like GPS and

Galileo Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642), commonly referred to as Galileo Galilei ( , , ) or mononymously as Galileo, was an Italian astronomer, physicist and engineer, sometimes described as a poly ...

: WGS84 and GTRF. The definitions and relationships among ITRF, ICRF and EOP are established by IERS conventions standards. , the most recent convention is the IERS Conventions (2010).

Earth orientation products

A mission of the IERS is to provide earth orientation information to the greater

geodesy Geodesy or geodetics is the science of measuring and representing the Figure of the Earth, geometry, Gravity of Earth, gravity, and Earth's rotation, spatial orientation of the Earth in Relative change, temporally varying Three-dimensional spac ...

community in the form of bulletins: * Bulletin A provides a rapid turnaround service for providing current EOP and a prediction model for EOP up to a year in the future. It is released weekly. * Bulletin B provides final measurements of EOP and is released monthly. * Bulletin C provides announcements of leap seconds. * Bulletin D provides DUT1 = (UT1 − UTC) to a 0.1 second precision.

References

External links

* *
Earth Orientation Center of the IERS : data and interactive analysis (Paris Observatory)
*
IERS International Celestial Reference Frame center
{{DEFAULTSORT:International Earth Rotation And Reference Systems Service Standards organizations in France International geodesy organizations Astronomy organizations 1987 establishments in France International organizations based in France Organizations based in Paris

History

Function

Earth orientation products

See also

References

Further reading

External links