The m-chi decomposition of hybrid dual-polarimetric radar data

The Mini-RF and Mini-SAR instruments are the first compact polarimetric space-based imaging radars. Their architecture is hybrid-polarimetric, transmitting (quasi-) circular polarization, and receiving orthogonal linear polarizations and their relative phase. The four Stokes parameters that are necessary and sufficient to fully characterize the observed backscattered EM field are calculated from the received linearly polarized data. The Stokes parameters can be used to formulate an m-chi decomposition of the scene, which is a new technique. This method facilitates unambiguous interpretation of surface features according to single (odd) or double (even) bounce signatures in the polarized portion of the reflections, and characterization of the randomly polarized constituents. The m-chi decomposition has proven to be robust in the event that the transmitted field is not perfectly circularly polarized. Analysis of lunar data suggests that an m-chi-psi three-component decomposition strategy should provide additional backscatter classification finesse. These methods are directly applicable to data anticipated from Earth-observing compact-polarimetric radars.