Synthetic Aperture Radar (SAR) uses a small antenna to move rapidly along the trajectory of a long linear array and radiate coherent microwave signals, and coherently process echoes received at different positions to obtain higher spatial resolution imaging radar. On the contrary, military radars placing on ground need large antenna to get high resolution.
As an active sensor, synthetic aperture radar has the characteristics of achieving all-day, all-weather ground observation without being restricted by light and climatic conditions, and can even obtain its cover information through the ground or vegetation. These characteristics make it has potential to be widely used in agriculture, forestry, water or geological and natural disasters. With Interference SAR, the deformation of large area ground surface and dams can be quickly and easily measured.