COSMO-SkyMed active calibrator: A sophisticated tool for SAR image calibration

In the framework of the COSMO-SkyMed mission1, Space Engineering has designed and manufactured four Active Calibrators (AC). An AC has a twofold function: ldr re-radiating the received radar signal with the required Radar Cross Section (RCS) and polarisation; ldr acquiring the received Synthetic Aperture Radar (SAR) pulses amplitude for successive elaboration. The AC will be used as a tool of the COSMO-SkyMed Calibration / Validation facility during the SAR commissioning phase to validate the on-board SAR and during the normal phase to maintain stable the image quality figures. The Active Calibrators will be operated together with a set of Passive Calibrators, characterised by a fixed RCS. The former ones have the great benefit of providing much higher RCS figures and recording capabilities than the latter ones. This paper describes the characteristics and performance of this Active Calibrator.