RISAT-1 SAR HRS Mode Data Quality Evaluation

This paper presents the quality evaluation of the data products from India's first SAR viz. Radar Imaging Satellite (RISAT-1) in High Resolution Spotlight (HRS) Mode having circular polarimetry from space. Sample scenes of Level-2 terrain corrected georeferenced products are acquired in different regions to observe geometric data quality in terms of Location accuracy and Internal Distortion. Further, parameters are identified to evaluate the image and radiometric data quality, such as Background to Peak Ratio (BPRatio), Integrated Side Lobe ratio (ISLR), Peak to Side Lobe ratio (PSLR), Radar Cross Section (RCS) of the Corner Reflector (CR), geometric resolution in the circular polarization mode (Level-1 Single Look Complex products). Results of the analysis are encouraging and meets the specifications. Location accuracy is better than 80m across track and 110m along-track, which is better than the SAR processor specifications. Further, geometric resolution achieved is within the range of 1.18 m for azimuth direction and 0.75 meter for range direction. RCS from image matched well with the CR's.