Altimetry is a technique for measuring height. Satellite altimetry measures the time taken by a radar pulse to travel from the satellite antenna to the surface and back to the satellite receiver. Combined with precise satellite location data, altimetry measurements yield sea-surface heights.

The Doris system is a french civil precise orbit determination and positioning system. It is based on the principle of the Doppler effect.

This section deals with microwave remote sensing which aims at extracting information on physical structure and electrical properties of an object or a scene by electromagnetical field analysis (sea, ice, ground, vegetation, urban areas, atmosphere, rain and clouds …).