AN EFFICIENT METHOD IN ARRAY-PROCESSING FOR ELIMINATING THE SIGNAL CANCELLATION PHENOMENA OF THE DIFFERENCING METHOD

In this paper, it is found that the Differencing method will fail to r esolve any signals in some cases for the reason that the signals are c ancelled out completely. The condition in which the signal cancellatio n 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 signal s in unknown noise fields. By splitting a uniform linear array into tw o identical subarrays, the DCM algorithm makes use of the fact that th e two subarrays possess identical covariance matrices of noise vectors , and that the covariance matrix (R) over tilde(s) of uncorrelated sig nals satisfies phi (R) over tilde(s) phi = (R) over tilde(s), where ph i is a diagonal matrix which indicates the displacement invariance bet ween the two subarrays, under the assumption that the signals and nois e are stationary, zero-mean, random processes. Finally, the DOA estima tion is performed by investigating the eigenstructure of the differenc e matrix of the covariance matrices (DCM) of the two subarrays. (C) 19 97 Elsevier Science B.V.