On radar polarization mixed target state decomposition techniques

The mathematical representations of mixed target states using Mueller, covariance, and density matrices are discussed, and the relationship between these matrices is shown. A decomposition technique due to J.R. Huynen (1970) is considered, and a simple algorithm for calculating it is demonstrated. It was shown that, in addition to the Huynen decomposition, exactly two other decompositions exist whose mixed-target-state components possess the same roll-invariant property as the distributed N-target mixed-target-state component in the Huynen decomposition. The mixed-target-state components of all three of these Huynen-type decompositions were shown to correspond to targets with circular polarization nulls. The characteristic decomposition was then discussed and applied to a simple example which demonstrated that its pure-state component provides the average target representation. It is noted that this decomposition may have applications to stationary target identification