Research On Array Direction Finding Technology In The Presence Of Mutual Coupling

Direction finding,also Direction of Arrival(DOA)estimation,is an important area of array signal processing research.Many high resolution algorithms have come out in the past decades.Most of the algorithms are based on ideal array model,whose performance will degrade seriously because of the array error.It is necessary to study on the algorithms in the presence of array error.This paper focus on the DOA estimation algorithms in the presence of mutual coupling.Firstly,some base knowledge of direction finding is introduced,including some kinds of array models and several classic algorithms.As for array error calibration,some common array error models are analysed,especially the mutual coupling model.The property of mutual coupling matrix and the influence of mutual coupling are discussed.Some mutual coupling calibration methods are introduced.Aiming at the high complexity of the DOA estimation algorithms for uniform linear arrays with mutual coupling,a low complexity algorithm is proposed.The algorithm combines the advantages of the propagator method and root method.Neither eigen-decomposition nor spectrum searching is needed.Simulation results show that the algorithm can reach good performance at middle and high SNR,while at low SNR,the performance of the algorithm is close to other algorithms if the the assumed number of sources is slightly overestimated.In case of strong mutual coupling,it also performs well.A new algorithm without setting any auxiliary sensors is also proposed for the 2-D DOA estimation in the presence of mutual coupling.Based on a new general mutual coupling model,the algorithm parameterizes the steering vector.Simulation results show a better performance achieved by the proposed algorithm than those auxiliary sensor-based ones,especially when the array size is small or the mutual coupling effect is strong.There is no loss of array aperture since auxiliary sensors are not needed.