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Research On Array Structure Optimization And DOA Estimation Of Non-Uniform Linear Arrays

Posted on:2019-06-07Degree:MasterType:Thesis
Country:ChinaCandidate:Y Y KongFull Text:PDF
GTID:2348330569487682Subject:Communication and Information System
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DOA(Direction of Arrival)estimation,that is spatial spectrum estimation,is the most important branch of the array signal processing technology.It has a wide range of applications in the MIMO radar multi-target positioning,underwater sonar detection,radio astronomy and other fields..The traditional DOA algorithm uses the uniform linear array as the receiving model,which limits the spacing between adjacent array elements of the array to no more than half the wavelength,which limits the number of sources to be smaller than the number of array elements.With the proposed Khatri-Rao(KR product)subspace method,it can use the Difference-Co-Array to perform DOA estimation and solve the DOA estimation problem for underdetermined(source number is greater than the number of array elements).The non-uniform linear array breaks through the limit of the half-wavelength of the uniform linear array,expands the degree of freedom(DOF)of the differential commonality array to improve the DOA estimation accuracy.Therefore,this thesis will focus on the optimization of the array structure of non-uniform linear arrays,focusing on the array structure of non-uniform linear arrays and the DOA estimation under the mutual coupling model.The main contents are summarized as follows:1.A non-uniform linear array based on the spacing of the largest adjacent array elements is proposed.The array is optimized on the physical array.It has the following advantages:when the number of array elements is fixed,its array structure is regular,in other words its array position set and degree of freedom have closed expressions,and the differential commonality array of the non-uniform linear array is fully continuous ULA;secondly,its degree of freedom has some improvements relative to nested array,coprime array,even improved nested array,extended coprime array,and augment nested array(ANAI-1 and ANAI-2).2.We study a new covariance matrix construction method.The covariance matrix has the same DOA estimation performance as the spatial smoothing matrix.However,the construction of the matrix is simple.The step of spatial smoothing and restoration of the rank is omitted,which greatly reduces the complexity of the algorithm.degree.At the same time,the performance advantages of non-uniform linear arrays with respect to nested array,improved nested array,coprime array,and augment nested array(ANAI-1 and ANAI-2)in DOA estimation are verified by simulations.3.study of DOA estimation under the mutual coupling model.The advantages of the non-uniform linear array proposed in this paper are analyzed.The first is to compare the weight function with the nested array,the coprime array,and the super nested array,which shows that its array structure is more sparse;It is verified through simulation that its DOA estimation performance under the mutual coupling model is better than the non-uniform linear array mentioned above.4.The DOA estimation of the optimal array using summation and difference is studied.The basic principle of summation and difference is analyzed.The degree of freedom it provides has a certain improvement over the difference co-array.The emphasis is placed on the advantage of using non-uniform linear arrays to maximize the degree of freedom based on the sum and difference co-array of the maximum adjacent array elements.Finally,it is verified through simulation that DOA estimation using summation difference is superior to non-uniform arrays such as nested array and coprime array.
Keywords/Search Tags:DOA estimation, non-uniform linear array, spacing between the largest adjacent array elements, mutual coupling, summation and difference array
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