DLR’s next generation of multi-band transponders for the calibration of fully polarimetric SAR missions

Abstract:
Since more than 25 years, DLR is playing a key role in the calibration of modern space borne SAR systems. With their high radiometric accuracy and operational flexibility, DLR’s in house-developed calibration transponders, also referred to as active radar calibrators (ARCs), have become a cornerstone of these calibration activities. With upcoming SAR instruments, low frequencies (L-band), high bandwidths and fully polarimetric acquisitions come into play and introduce new challenges to the design of calibration transponders. For this propose, DLR has developed an entirely new tran-sponder concept, a polarimetric active radar calibrator (PARC), which operates both in L- and X-band and supports fully polarimetric acquisitions with an outstanding accuracy. We discuss the potential and challenges of PARCs for the calibration of future SAR missions such as ROSE-L and HRWS. We then introduce the overall concept and the design of various newly developed subsystems of our prototype transponder, which is currently being assembled in our lab.