DOA estimation for wide-band signal using FFT interpolation technique

A method for wide-band DOA estimation is proposed in this paper. By using FFT interpolation technique, virtual arrays outputs of each frequency bin of wide-band signal can be obtained from real array outputs, and these virtual arrays have the same array manifold, so DOA's can be estimated from the outputs of virtual arrays. Ordinarily, preliminary source locations, which are used to construct focusing matrices, should be estimated prior to forming covari-ance matrices, whereas, the method which needs information of source locations suffers from an asymptotic bias, and the bias increases with the deviation of preliminary source location from the true DOA's. The method proposed in this paper, by preprocessing the array outputs, the common covariance matrices can be formed, and DOA's can be estimated by using conventional method.Resultsof DOA estimation are unbiased because this method needn't prior information of source locations. Simulation results are provided to illustrate: the effectiveness of proposed method.