Enhanced BNC Approach for Noncircular Signals Direction Finding With Sparse Array in the Scenario of Impulsive Noise

Sparse array is popular in the field of array signal processing. However, in the direction of arrival (DOA) estimation, most research on sparse array assumes Gaussian noise, resulting in a model mismatch in the practical scenarios of impulsive noise. We investigate the estimation performance of the bounded nonlinear covariance (BNC) matrix-based methods, which can be used to replace the original data covariance matrix of the received signal and achieve good robustness to the impulsive interference. We propose an enhanced BNC (EBNC) matrix with a noncircular signal for a nested array in the scenario of impulsive noise. The proposed EBNC matrix can fight against the impulsive noise outliers and its boundedness and convergence are shown. The proposed method's performance is assessed with simulations. Simulation results indicate that the proposed method provides better performance in DOA estimation than the classical BNC, correntropy-based covariance matrix, and Gaussian covariance-based methods, especially in highly impulsive noise scenario.