World Magnetic Model
Encyclopedia
The World Magnetic Model (WMM) is a large spatial-scale representation of the Earth's magnetic field. It consists of a degree and order 12 spherical-harmonic expansion of the magnetic potential of the geomagnetic main field generated in the Earth’s core. Apart from the 168 spherical-harmonic "Gauss" coefficients, the model also has an equal number of spherical-harmonic Secular-Variation (SV) coefficients predicting the temporal evolution of the field over the upcoming five-year epoch. WMM is the standard geomagnetic model of the United States Department of Defense
(DoD), the Ministry of Defence (United Kingdom)
, the North Atlantic Treaty Organization (NATO), and the World Hydrographic Office (WHO) navigation and attitude/heading reference. It is also used widely in civilian navigation systems. The WMM is produced by the U.S. National Geophysical Data Center (NGDC) in collaboration with the British Geological Survey (BGS). The model, associated software, and documentation are distributed by the National Geophysical Data Center
(NGDC) on behalf of National Geospatial-Intelligence Agency
(NGA). Updated model coefficients are released at 5-year intervals, with the current model (WMM2010) expiring on December 31, 2014.
United States Department of Defense
The United States Department of Defense is the U.S...
(DoD), the Ministry of Defence (United Kingdom)
Ministry of Defence (United Kingdom)
The Ministry of Defence is the United Kingdom government department responsible for implementation of government defence policy and is the headquarters of the British Armed Forces....
, the North Atlantic Treaty Organization (NATO), and the World Hydrographic Office (WHO) navigation and attitude/heading reference. It is also used widely in civilian navigation systems. The WMM is produced by the U.S. National Geophysical Data Center (NGDC) in collaboration with the British Geological Survey (BGS). The model, associated software, and documentation are distributed by the National Geophysical Data Center
National Geophysical Data Center
The National Geophysical Data Center provides scientific stewardship, products and services for geophysical data describing the solid earth, marine, and solar-terrestrial environment, as well as earth observations from space....
(NGDC) on behalf of National Geospatial-Intelligence Agency
National Geospatial-Intelligence Agency
The National Geospatial-Intelligence Agency is an agency of the federal government of the United States with the primary mission of collecting, analyzing and distributing geospatial intelligence in support of national security. NGA was formerly known as the National Imagery and Mapping Agency ...
(NGA). Updated model coefficients are released at 5-year intervals, with the current model (WMM2010) expiring on December 31, 2014.