Linking Reference Target Properties to Its Perceived RCS in SAR Images

Abstract:
A synthetic aperture radar (SAR) system is a measurement instrument which maps radar reflectivity. Prior to scientific and commercial use, the SAR system is typically calibrated, and here the focus shall be on radiometric calibration. Reference point targets like active transponders or passive corner reflectors provide a reference reflectivity against which the instrument offset can be determined. Up to now, no direct link between the reference point target properties (like its frequency response) and its perceived backscattering was available. In this paper it is proposed to close this gap using a point target SAR simulator, which links the target properties to the derived absolute calibration factor. This allows to derive correction factors which result in a normalization of calibration results over SAR mode settings and target properties.