Geodesy
Videos
Geodesy or geodetics is the science of measuring and representing the geometry, gravity, and spatial orientation of the Earth in temporally varying 3D space. It is called planetary geodesy when studyi
Geoid, an approximation for the shape of the Earth; shown here with vertical exaggeration (10000 vertical scaling factor).
Height measurement using satellite altimetry
GPS Block IIA satellite orbits over the Earth.
Geodetic control mark
Satellite geodesy
Videos
Satellite geodesy is geodesy by means of artificial satellites—the measurement of the form and dimensions of Earth, the location of objects on its surface and the figure of the Earth's gravity field b
Geodesy
…such coordinate systems are typically geocentric, with the Z-axis aligned to Earth's (conventional or instantaneous) rotation axis. Before the era of satellite geodesy, the coordinate systems associated with a geodetic datum attempted to be geocentric, but with the origin differing from the geocenter by hundreds of…
Wettzell Laser Ranging System, a satellite laser ranging station
Artist's conception of GRACE
This graph shows the rise in global sea level (in millimeters) measured by the NASA/CNES ocean altimeter mission TOPEX/Poseidon (on the left) and its follow-on mission Jason-1. Image credit: University of Colorado