Paper Title
A Generalized Spatial Differencing Method for Direction-of-arrival Estimation of Uncorrelated and Coherent Sources

Abstract
Direction-of-arrival (DOA) estimation algorithms such as subspace based techniques have been extensively studied over the past few decades. However, these algorithms are not applicable to DOA estimation for coherent signals (i.e., fully correlated). As an attempt to remove the correlation between incident signals, a spatial differencing method (SDM) was proposed under the condition that both the uncorrelated and the coherent signals exist. By taking the advantage of the property that the information of the coherent signals can be extracted from the received data, SDM could increase the maximum number of resolvable sources. In several cases, however, the conventional SDM may fail to detect coherent signals because the conventional spatial differencing matrix is derived from the part of the covariance matrix. In this paper, a generalized spatial differencing method is proposed for DOA estimation of coherent signals by using the entire spatial differencing matrices. Through the simulations, the proposed method is confirmed that it resolve more coherent sources and also improve the accuracy of the DOA estimates. Keywords- DOA Estimation, Uncorrelated Signals, Coherent Signals, Spatial Smoothing, Spatial Differencing Method, Uniform Linear Array.