A Study Of DOA Estimation Method Of ULA With Array Element Structure Information

Direction of arrival (DOA) estimation is one of the important research contentand successive hot point in array signal processing, the main purpose of DOAestimation is to use and process the measurement data which received by sensor array,estimate and extract parameters such as the direction of arrival of the spatial signal tobe measured, the number of signals, the power and cross correlation information.DOA has been widely applied in many practical engineerings includingcommunication, radar, military, earthquake, etc.Firstly, for the conventional MUSIC algorithm and ESPRIT algorithm can noteffectively achieve DOA estimation of the coherent source. Based on modifiedMUSIC (MMUSIC), introducing the transformation matrix and considering the auto-correlation and cross-autocorrelation of the array output and the correspondingtransformed matrix, and combined with total least-squares ESPRIT algorithm, animproved ESPRIT algorithm (IM-ESPRIT) that is suitable for the cases of thenon-coherent and coherent sources has been proposed. it is shown by the numericalsimulation that IM-ESPRIT algorithm has the better estimation accuracy under thecondition of the small angle interval of the coherent sources and lower SNR.Secondly, this study of the DOA estimation algorithms found that the number ofsignals is a need to pre-known key parameter of many DOA algorithms. This paperused ULA sensor array delay value array element characteristics and specificreference array element signal (such as the first array element of array) and thecross-correlation function of other array element signals, through the delay differentialoperation, derived a matrix equations for DOA estimation, the theory shown that thecoefficient matrix equation is Hankel matrix, we resolved Hankel matrix with singularvalues or characteristic values decomposition, the number of singular values orcharacteristic values only related to the number of signal sources; meanwhile.Moreover, under the condition of the number of signal sources is unknown, accordingto the preset number of the signal source, we can construct variable dimension Hankelmatrix correspondently. By the nature of Hankel matrix, we proposed a singular valuedecomposition algorithm to estimate the number of signal sources which based onarray element time delay structure information (Array element Time delay Structuralinformation Singular Value Decomposition, ATDS-SVD). To the following threecases such as independent signal source, coherent signal source and mixed-signalsource (coherent and non-coherent sources coexist), we used the ATDS-SVDalgorithm to simulate and analysis the experiment around estimating the number ofsignal sources. Compared with the conventional number of signal source estimation method (AIC, MDL, etc.), it is shown by the simulation results that ATDS-SVDalgorithm can estimate the number of coherent and non-coherent signal sourcesynchronously and has asymptotic consistency, better stability and estimationaccuracy.Finally, we used the Hankel matrix to simulate programming and analysis theDOA estimation for ULA with IM-ESPRIT algorithm angle estimation principle. It isshown by the simulation experiment that the IM-ESPRIT algorithm is suitable forestimating DOA direction under the condition of different signal sources with Hankelmatrix; Especially, this algorithm showed better stability, estimation accuracy andresolution under the cases of lower SNR, furthermore, we demonstrated theeffectiveness and feasibility of the DOA estimation algorithm preliminarily.