International prime meridian used for GPS and other systems
This article is about Earth's current international standard prime meridian. For the historical prime meridian, see Prime meridian (Greenwich).
For the general concept, see prime meridian.
0°
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Modern IERS Reference Meridian on Earth
Countries that touch the Equator (red) and the Prime Meridian (blue)
The IERS Reference Meridian (IRM), also called the International Reference Meridian, is the prime meridian (0° longitude) maintained by the International Earth Rotation and Reference Systems Service (IERS). It passes about 5.3 arcseconds east of George Biddell Airy's 1851 transit circle which is 102 metres (335 ft) at the latitude of the Royal Observatory, Greenwich.[1][2][a] Thus it differs slightly from the historical Greenwich Meridian.
It is the reference meridian of the Global Positioning System (GPS) operated by the United States Space Force, and of WGS 84 and its two formal versions, the ideal International Terrestrial Reference System (ITRS) and its realization, the International Terrestrial Reference Frame (ITRF).
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^IRM on grounds of Royal Observatory from Google Earth Accessed 30 March 2012
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and 23 Related for: IERS Reference Meridian information
services of IERS are at the Paris Observatory. UT1 is the non-uniform time defined based on the Earth's rotation. It defined the IERSReferenceMeridian, the...
prime meridian is the IERSReferenceMeridian. It is derived, but differs slightly, from the Greenwich Meridian, the previous standard. A prime meridian for...
second of mean solar time (such as UT1) at 0° longitude, (at the IERSReferenceMeridian). The mean solar day is slightly longer than 86,400 SI seconds...
on the meridian of 180° longitude, roughly down the middle of the Pacific Ocean, and halfway around the world from the IERSReferenceMeridian, the successor...
at the northernmost part of Earth. The Arctic region, from the IERSReferenceMeridian travelling east, consists of parts of northern Norway (Nordland...
The WGS 84 meridian of zero longitude is the IERSReferenceMeridian, 5.3 arc seconds or 102 metres (335 ft) east of the Greenwich meridian at the latitude...
the meridians or points chosen to define it. Below is a list of the sovereign states in both the Western and Eastern hemispheres on the IERSReference Meridian...
sovereign states in both the Western and Eastern hemispheres on the IERSReferenceMeridian, in order from north to south: Denmark, due to the entirety of...
Prime Meridians that have been used, are used, or are proposed Greenwich Meridian established by the International Meridian Conference IERSReference Meridian...
be set to Mecca Time, in an attempt to replace the IERSReferenceMeridian as the prime meridian for global time keeping, but the clock is set to Arabia...
Mean Time. The 'Prime Meridian', 0°, was originally defined as being the Greenwich meridian but is now the "IERSReferenceMeridian": they are not quite...
illuminated blue line underneath the tracks at street level. The modern IERSReferenceMeridian used by GPS crosses the tracks approximately 117 metres further...
lies at 16° 38′ 22″ W of the current international prime meridian, the IERSReferenceMeridian through Greenwich. Cartographers like Mercator, Hondius...
(GST), which is sidereal time on the IERSReferenceMeridian, less precisely termed the Greenwich, or Prime meridian. There are two varieties, mean sidereal...
appears in other records and lists of ships stores. The earliest recorded reference that can be said with certainty to refer to a marine sandglass dates from...
estimates, given by the IERS Conventions, "should not be mistaken for conventional values, such as those of the Geodetic Reference System GRS80 ... which...
least 600 BC, was a type of plumb-line called a merkhet. A north–south meridian was created using two merkhets aligned with Polaris, the north pole star...
Time, which is the mean solar time at 0 degrees longitude (the IERSReferenceMeridian). Civil time is based on UT (actually UTC), and civil calendars...
IRM may refer to: IERSReferenceMeridian Illinois Railway Museum Illinois Reserve Militia, state defense force active during World War II Bureau of Information...
point called the IERSReference Pole, or IRP, is used as the origin; the x-axis is in the direction of IRM, the IERSReferenceMeridian; the y-axis is in...
the official Prime Meridian of the world, a status it held for a century until it was superseded by the related IERSReferenceMeridian, which runs parallel...
Global Information
