Terrestrial reference systems and frames

IERS Technical Note
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Terrestrial Reference Systems and their realizations. A Terrestrial Reference System (TRS) is a spatial reference system co-rotating with the Earth in its diurnal motion in space. In such a system, positions of points attached to the solid surface of the Earth have coordinates which undergo only small variations with time, due to geophysical eects (tectonic or tidal deformations). In the physical model adopted in astrogeodesy, a TRS is modeled as a reference trihedron close to the Earth and co-rotating with it. In the Newtonian framework, the physical space is considered as a Euclidean ane space of dimension 3.