A method of measuring SAR calibration constant using ocean

SAR calibration is one of the most important technique of measurable observation and to calibrate SAR images to normalized radar cross sections (NRCS) a calibration constant is required. Usually the calibration constant is determined by analyzing measurements of corner reflectors or transponders. However, for Global Monitoring mode of ASAR, we can not facture so large radar cross section (RCS) calibrators to satisfy the signal clutter ratio (SCR) of measurement. So we put forward a method to measure the calibration constant based on knowledge of the dependency of the NRCS on the ocean surface wind, which is described by the C-band model CMOD4. We validate our method using real data of ASAR mode.