Importance sampling for NMF class of STAP detectors

Importance sampling (IS) techniques are applied to space-time adaptive processing (STAP) radar detection algorithms for performance characterization via fast estimation of false alarm probabilities (FAP´s). The work here builds on and extends the initial thrust in this area provided in a recent paper. The theory of the normalized matched filter (NMF) and normalized adaptive MF (NAMF) detectors is briefly discussed and a new variant, the envelope-law NAMF detector, is presented. New IS biasing techniques, using rotation of data vectors and 2-dimensional biasing, are proposed and used for fast simulation. The envelope (or E-NAMF) detector is also analyzed and its detection probability is compared with that of the NAMF detector for fluctuating and non-fluctuating targets in homogeneous and nonhomogeneous backgrounds