The advantage of radar is that it can detect distant targets both day and night, and is not obstructed by fog, clouds, or rain. It has the characteristics of all-weather and all-weather, and has a certain penetration ability. Therefore, it has not only become an essential electronic equipment in military affairs, but also widely used in social and economic development (such as meteorological forecasting, resource exploration, environmental monitoring, etc.) and scientific research (astronomical research, atmospheric physics, ionospheric structure research, etc.). Satellite and airborne synthetic aperture radar have become very important sensors in remote sensing today. A radar targeting the ground can detect the precise shape of the ground. Its spatial resolution can reach several meters to tens of meters and is independent of distance. Radar has also shown great potential for applications in flood monitoring, sea ice monitoring, soil moisture investigation, forest resource inventory, geological survey, and other fields.