Direction of arrival estimation method by fusing sparse and dense subarrays of nested array
In order to improve estimation performance by effectively using the geometric structure of nested arrays containing sparse and dense subarrays,this paper proposes a DOA estimation method by finding directions on two subarrays and then merging them.Through theoretical analysis and practical cases,the results can clarify whether the direction finding results of two subarrays of the nested array can eliminate the ambiguity of source angle estima-tion.The results also determined whether matching errors accompanied the ambiguity resolution of the coprime ar-ray.First,the root-MUSIC method without peak search is used to solve the direction finding results on two subar-rays of nested arrays.Then,for the sparse subarray with N times the half-wavelength spacing between elements,it is deduced that the complex root can be opened for N times,thus obtaining a high-precision estimation with an am-biguity angle.Finally,the high-precision DOA estimation is obtained by combining the minimum variance criterion with the direction finding results of dense subarrays with low precision but no ambiguity.Compared with the existing algorithms of the nested array,this algorithm improves the accuracy and resolution of DOA estimation and reduces the computational complexity because it does not need the covariance of two subarrays.Furthermore,it can support the distributed configuration of nested arrays.Simulation results verify the effectiveness of the proposed algorithm.
nested arrayroot-MUSICvariance fusionsparse and dense subarraysdirection of arrival estimationsparse subarraydense subarrayambiguity resolution