Research On Direction Of Arrival Estimation Technology Based On Conjugate Spatial-Temporal Augment

Direction of arrival is one of the most important research directions in array signal processing.It has a wide range of applications in military and national economic fields such as communications,earthquake,radar,exploration,and biomedicine.The classical DOA estimation methods are mostly based on uniform linear arrays,so the number of signal sources that can be estimated by traditional estimation algorithms is limited by the number of array elements.In order to avoid angle blur,the spacing of array elements must be no more than half the wavelength of the signal.The array aperture resulting in a uniform line array is limited.In recent years,a non-uniform array represented by a coherent array is used as a special sparse array.After expansion,the virtual array has more virtual array elements,which greatly improves the effective aperture and degree of freedom of the array.The problem of limited freedom in a uniform line array.Therefore,studying the expansion method of the virtual array and the reasonable array structure can effectively improve the aperture and degree of freedom of the array.Based on the mutual quality array,this paper proposes corresponding improvement measures around the optimization of the array structure and the corresponding virtual expansion methods.The main contents are as follows:Firstly,the received signal model of uniform linear array is introduced.The subspace algorithm and sparse reconstruction algorithm based on uniform linear array are simulated.The DOA estimation performance based on two algorithms under uniform linear array is compared.Secondly,it introduces the received signal model of the co-array array and the basic principle of the virtual expansion of the co-array array,and analyzes the characteristics of the MUSIC algorithm and the sparse reconstruction algorithm based on the co-array array,based on the homogeneous array and based on uniformity.The DOA estimation algorithm of the array was simulated and the estimation ability of the number of sources and the accuracy of DOA estimation under two array structures were compared.The received signal model of parallel inter-matrix array is introduced.The characteristics of DOA estimation algorithm based on parallel symmetry space-time conjugate space-time extension are analyzed.Two improved DOA estimation methods based on conjugate space-time extension are proposed.The improved method further expands the array by adding one or two additional physical array elements and utilizing the idea of conjugate space-time augmentation,and obtains more virtual array elements and degrees of freedom than the existing methods.Then the number of virtual array elements equivalent to the three methods after conjugate space-time expansion is compared.Finally,the experimental results show that the two improved methods have higher estimation accuracy and resolution.