Research On DOA Estimation Algorithm For Sparse Array

DOA estimation is an important research direction of radar countermeasure reconnaissance.In recent years,the battlefield electromagnetic environment is more complex,and the traditional estimation algorithms are difficult to meet the needs of modern warfare.A sparse array antenna is an array antenna with element spacing larger than the source half wavelength.Compared to the conventional full rank array,the sparse array has larger array aperture,higher direction finding accuracy,stronger angular resolution and more simultaneous processing of the number of sources.In this paper,the direction of sparse array direction finding is studied,The superiority of the proposed algorithm is proved by simulation.The main work is as follows1.The ambiguity characteristics of the sparse array are studied,and the relation between the relative position of the array and the angle estimation of the sparse array is deduced.Analysis of the common denominator and direction finding array the relative position of the angle ambiguity connection.through the method of adding element in the uniform sparse array,solve the problem of sparse array angle ambiguity.2.The problem of sparse array multi signal processing is studied,and a nested array DOA estimation algorithm based on Toeplitz matrix construction is proposed.By processing the covariance matrix of the received signal of the array,the two level nested array is extended to the virtual equal spacing linear array,which increases the array aperture and the array freedom.Then using the processed signal to construct the pseudo covariance matrix,and combined with the MUSIC algorithm,the high-precision DOA estimation is achieved under the condition that the number of the elements is less than the number of the incident signals.3.On the two level nested array single snapshot DOA estimation method,proposed a combination of two single snapshot DOA search method.Firstly,the nested array is divided into two sub arrays,such that the array spacing is equal to the half wavelength of the source and the half wavelength of the source.The use of sub array single snapshot data we construct a pseudo covariance matrix,using MUSIC to get high precision without fuzzy incident angle.4.The DOA estimation problem of non-uniform sparse arrays is studied.A DOA estimation algorithm based on the virtual array transform is proposed.The first of the non-uniform received signal covariance matrix vector sparse array processing,through the Khatri-Rao product operation model of the received signal,and then through the virtual array transformation of uniform line array into the same array aperture.Finally,the DOA estimation is realized by combining the subspace class algorithm.