An adaptive loop gain CLEAN algorithm based on spatial source coherence for port/starboard discrimination

Near-linear arrays are widely used in the direction of arrival estimation. However, because if their cylindrical symmetry, port/starboard discrimination (PSD) remains a challenge. This paper introduces an adaptive loop gain CLEAN algorithm based on spatial source coherence (A-CLEAN-SC) to address the PSD problem and detect weak targets obscured by interference-induced mirror artifacts. The detection probability and the false alarm probability are formulated as functions of the loop gain, and the loop gain is adaptively determined by maximizing the difference between the detection probability and the false alarm probability. Simulations and experiments demonstrate that A-CLEAN-SC achieves a superior trade-off between mirror suppression and weak targets detectability compared to other methods (minimum variance distortionless response, blind source separation-port/starboard discrimination, CLEAN, and CLEAN based on spatial source coherence), particularly under steering vector mismatch conditions in near-linear arrays.