WGS84: World Geodesic System - revision dating from 1984
The World Geodesic System defines a reference frame for the earth, based on a reference geoid, using a reference ellipsoid.
WGS84 is a coordinate system, defining a reference frame for the earth, thanks to primary and secondary parameters :
- primary parameters define the shape of the ellipsoid of the earth, its angular speed and its mass
- secondary parameters define a detailed gravity model of the earth
GPS coordinates from a GPS receiver actually are a latitude, a longitude and an altitude calculated according to the WGS84 coordinate system.