Two techniques for using distributed clutter for calibrating a polarimetric radar are given: one uses clutter only but requires knowlege of theoretical clutter polarization ratios; the other requires the use of an in-scene trihedral but requires no foreknowledge of clutter statistics. These techniques are developed and contrasted with the more traditional technique which uses a set of in-scene calibration reflectors, such as trihedrals and dihedrals. A method is proposed and evaluated for estimating and removing the effects of additive noise on the measured clutter covariance matrix. Results are given of the application of this technique to MIT Lincoln Laboratory's Advanced Dectection Technology Sensor (ADTS) synthetic aperture radar.
R. M. Barnes,
"Polarimetric Calibration Using Distributed Clutter", Proc. SPIE 1101, Millimeter Wave and Synthetic Aperture Radar, (14 August 1989); doi: 10.1117/12.960514; https://doi.org/10.1117/12.960514