Practical joint domain localised adaptive processing in homogeneous and nonhomogeneous environments. Part 2: Nonhomogeneous environments

The second part of this two-part paper deals with space-time adaptive proce ssing (STAP) in nonhomogeneous environments. This paper introduces a new tw o-dimensional nonstatistical, direct data domain (D-3) STAP algorithm and a hybridisation of this D-3 approach with the joint domain localised (JDL) a lgorithm. The D-3 algorithm replaces the non-adaptive transform used in Par t 1 thereby suppressing discrete interference. A second stage of statistica l processing in the angle-Doppler domain suppresses residual correlated int erference. This new two-stage hybrid STAP technique allows for the applicat ion of the JDL algorithm within range cells determined to be nonhomogeneous . The development here draws heavily on the formulation presented in Part 1 of this paper. The work presented brings together two different aspects of STAP research: statistical and D-3 processing. In doing so, this research fuIfils an important need in the context of practical STAP, particularly kn owledge-based algorithms. The envisioned system uses multi-pass processing to determine key information regarding the interference scenario. Depending on the homogeneity of the interference, the algorithm in Part 1 or that in Part 2 of the paper may be used.