SAR radiation calibration constant measurement method based on calibration satellite

The invention discloses an SAR radiation calibration constant measurement method based on a calibration satellite. The method comprises the following steps: 1, determining orbit parameters of the calibration satellite; 2, calculating the distance between the calibration satellite and the SAR satellite in the surveying and mapping zone, and selecting the calibration satellite; 3, imaging the selected calibration satellites by using the SAR satellites to obtain SAR images of the calibration satellites; 4, extracting energy of all effective calibration satellites according to the SAR images of all the calibration satellites; 5, measuring a calibration constant by utilizing the energy of the effective calibration satellite; and 6, converting the calibration constants, thereby completing the measurement of the SAR satellite calibration constants. According to the method, the calibration satellite carrying the passive calibrator can be taken as a reference target, the calibration constant measurement frequency is i