Radiometric Calibration of RISAT-1 SAR Image Using Integral Method

Abstract

Synthetic aperture radar plays a key role in remote sensing applications ranging from mapping earth’s surface to disaster monitoring applications. Accuracy or correctness of SAR data or images is commendable in all these applications. Component aging and gain fluctuations in receiver and transmitter and atmospheric factors cause deviations in SAR performance which necessitates frequent SAR calibration. Validating the measured value against the standard or reference value is known as SAR calibration. SAR calibration is also essential as to compare the measured data with similar other sensors. This paper brings out several aspects of RISAT-1 FRS mode SAR image calibration using standard point targets such as corner reflectors. Integral method of calibration is demonstrated on RISAT-1 SAR sample image and the calibration factor is determined and validated.