Direction estimation of coherent narrowband signals using spatial signature

A computationally efficient spatial signature (SS) based method is proposed for estimating the directions-of-arrival (DOAs) of coherent narrowband signals impinging on a uniform linear array (ULA). The normalized SS of the coherent signals is blindly estimated from the signal eigenvector of the array covariance matrix and then is used to estimate the directions with a modified Kumaresan-Prony (K-P) method, where a linear prediction (LP) model is combined with "subarray" averaging. The proposed method not only has the maximum permissible array aperture and computational simplicity, it also better resolves closely spaced coherent signals with small length of data and at lower signal-to-noise ratio (SNR).