Geodesy is the discipline that deals with the measurement and representation of the geometry and physics of the Earth and its temporal variations. This includes
- the global figure of the Earth,
- the spatial orientation and rotation,
- the shape and deformation of the surface,
To accomplish its mission, geodesy applies the most recent and advanced space techniques like, e.g., astronomical very long baseline interferometry, global positioning systems, tracking of satellites by laser and microwave techniques, remote sensing, satellite altimetry, satellite gradiometry.
These techniques are applied for, e.g.,
- extremely precise point positioning and navigation,
- establishment and maintenance of terrestrial and celestial reference frames,
- representation of the Earth's topography (over land and ice, and beneath the oceans),
- representation of the ocean surface and monitoring of sea level changes,
- of crustal movements and mass displacements,
- modelling mass transport within and between land, ice, atmosphere and oceans,
- study of the Earth's gravity field, and its variability.