Cramer-Rao bound of direction of arrival estimation in presence of mutual coupling

Direction-of-arrival (DOA) estimation is one of the major topics in array processing. However, the previous works on DOA estimation and the corresponding Cramer-Rao bound (CRB) were constrained within the spatially white noise field. The mutual coupling brings distortion to the array manifold and spatial correlation to the signals as well as noise. Therefore, the influence of mutual coupling to the CRB of DOA is investigated in the case of spatially coloured noise in this paper. A signal model in presence of mutual coupling is proposed and the closed-form expression of the corresponding CRB is derived. The numerical simulations are presented to study the property of this new CRB and it can provide very useful insight into the impact of mutual coupling. The study of this paper is very helpful to the application of DOA algorithms and contributes to the exploration of performance improvement in DOA estimation.