Development and performance validation of L-, C- and X-band active radar calibrators (ARC) by means of laboratory tests and SIR-C/X-SAR experiments

CO.RI.S.T.A. (Consortium for Research on Advanced Remote Sensors), in collaboration with the Universities of Naples and Bari (Italy), has been developing a set of C-band ARCs, deployed during several synthetic-aperture radar (SAR) campaigns (TOPSAR 1991, ERS-1 1992 and 1993). The acquired experience has led to the design and development of a new set of ARCs operating in L-, C- and X-bands which have been accurately characterized by means of laboratory measurements and successfully used during SIR-C/X-SAR campaigns in April and October 1994 on the Matera back-up test site, Southern Italy. The paper describes the design principles and laboratory analyses performed to characterize the hardware performance, with specific attention on the measurement of gain, RCS and propagation delay and their dependence on the temperature. The results obtained from the analysis of single-look complex SAR images acquired from the SIR-C/X-SAR instrument are also presented, showing satisfactory performance of the active calibrators