Research On DOA Estimation Based On Subspace Technology

The direction of arrival(DOA)estimation has been raised so far,and many important results have been achieved,it becomes a hot topic in the fields of smart antenna and radio direction finding.The basic problem of the direction of arrival(DOA)estimation is to determine the location of the target signal in the space by estimating the azimuth of the signal to the array.In this paper,the subspace class estimation method in spatial spectrum estimation is studied.The performance of the multiple signal classification(ESPRIT)algorithm,the rotation invariant subspace(MUSIC)algorithm and the propagation operator(PM)algorithm in one-dimension space are analyzed.On the basis of L-array,a two-dimensional ESPRIT algorithm,Root-MUSIC algorithm and PM algorithm are proposed respectively.In the research of MUSIC algorithm and PM algorithm,we utilize a uniform linear array to study the changes in the spatial spectral function curve by changing the number of array elements in the array model,the SNR and the number of snapshots in the signal model.The influence of these parameters on the performance of MUSIC algorithm and PM algorithm is analyzed.When it comes to ESPRIT algorithm,we change the parameters in the signal model and the array model and take advantage of Monte Carlo experiments to analyze the root mean square error and compare the performance of ESPRIT algorithm under different parametersIn the 2-D DOA estimation,we propose an improved ESPRIT algorithm.In this method,the array elements distributed on the X axis and the Z axis constitute the L array.The array is divided into four subarrays,and four intercorrelation matrices are calculated.The eigenvalue decomposition of the matrix of four cross correlation matrices is used to obtain the signal subspace estimation,then using ESPRIT algorithm for two-dimensional angle estimation.This method does not require spectral peak search,avoids extra pairing operation,and has high estimation accuracy,but the computational complexity of the method is large.In order to improve the computational complexity,a 2-D DOA estimation algorithm based on PM algorithm is proposed.This method simplifies the computation by avoiding the eigen decomposition of the covariance matrix,and the performance of angle estimation is better.Finally,a two-dimensional root seeking MUSIC algorithm is proposed.Although the traditional MUSIC algorithm can achieve asymptotic unbiased estimation,it needs spectral peak search and large amount of computation.The root MUSIC algorithm independently estimates the direction of arrival of the X and Z axis array to get the correct combination of the two-dimensional angles.The method does not need the spectral peak search,and the estimation accuracy is close to the two-dimensional MUSIC algorithm,which has certain practicability.