Coherent interference suppression with an adaptive array using spatial affine projection algorithm

This paper proposes a new algorithm, namely the spatial affine projection (SAP) algorithm, for adaptive array beamforming in the presence of multiple coherent interferers. The SAP algorithm applies the affine projection (AP) algorithm to adaptive beamformers in the space domain. Combining the decorrelation property of the AP algorithm with that of the spatial smoothing (SS) algorithm, the SAP algorithm achieves coherent interference suppression and fast convergence simultaneously. Computer simulation shows that the SAP algorithm incorporating a subtractive preprocessor (SP) outperforms the existing algorithms by placing deeper nulls and converging faster. The convergence of the SAP algorithm is comparable to that of the SS scheme using the RLS algorithm while the computational complexity of the SAP algorithm is close to that of the SS scheme using the normalized LMS algorithm.