THE SIR-C X-SAR ITALIAN EXPERIMENTS AT MATERA - INSTRUMENTATION AND MEASUREMENT RESULTS/

This paper presents results related to the shuttle imaging radar C and X-band synthetic aperture radar (SIR-C/X-SAR) Italian experiments car ried out at the calibration backup supersite CB1 (Matera, in southern Italy). C-, L- and X-band active radar calibrations (ARC) were deploye d for radiometric analysis of the microwave instrument on board the NA SA space shuttle. The main objectives of this investigation-namely, gr ound instrumentation validation, image quality assessment, and radiome tric calibration-are accomplished by making measurements from the sign atures of the ARCs, whose radar cross section (RCS) was known from lab oratory measurements. The expected RCS of each deployed target, as see n by the sensor, is reconstructed on the radiometrically calibrated im ages, faking into account the uncertainties in the measurements made o n the impulse response function and the accuracy of the laboratory tes ts. Numerical results derived from the standard single-look complex (S LC) products provided by the Jet Propulsion Laboratory and by the Germ an and Italian processing and archiving facilities show good performan ce of the ARCs and of the SAR processors, also indicating acceptable s tability of the calibration parameters of SIR-C and X-SAR. A simple se lf-organizing clustering algorithm is applied to the areas centered on the ARCs to obtain histograms of scattering properties of bare and pl oughed soil. The comparison with backscattering statistics databases g ives good agreement with the backscatter data derived from the calibra ted SAR imagery. (C) Elsevier Science Inc., 1997.