GRS – Geodetic Reference System

A Geodetic Reference System defines the shape, size, and gravity parameters of the Earth to provide a standardized framework for positioning, mapping, and geodetic measurements worldwide. It establishes the conventions and constants needed for consistent calculations of coordinates, heights, and gravity values across regions and techniques.

GRS80 (Geodetic Reference System 1980) is a specific realization of this concept, adopted by the IUGG in 1979. It is defined by four physical parameters: equatorial radius, geocentric gravitational constant, dynamic form factor, and Earth’s angular rotation rate. GRS80 provides a precise Earth model used for global and regional datums, height computations, gravity modeling, and the realization of modern geodetic reference frames.