An efficient method in array processing for eliminating the signal cancellation phenomena of the differencing method

Abstract

In this paper, it is found that the Differencing method will fail to resolve any signals in some cases for the reason that the signals are cancelled out completely. The condition in which the signal cancellation phenomenon will occur is derived. In order to overcome the drawback of the Differencing algorithm, an extension of the differencing method, named DCM by us, is proposed to resolve two highly correlated signals in unknown noise fields. By splitting a uniform linear array into two identical subarrays, the DCM algorithm makes use of the fact that the two subarrays possess identical covariance matrices of noise vectors, and that the covariance matrix R ̃ s of uncorrelated signals satisfies Φ R ̃ sΦ = R ̃ s , where Φ is a diagonal matrix which indicates the displacement invariance between the two subarrays, under the assumption that the signals and noise are stationary, zero-mean, random processes. Finally, the DOA estimation is performed by investigating the eigenstructure of the difference matrix of the covariance matrices (DCM) of the two subarrays.