Research On 2d DOA Estimation Algorithm Based On Double Layer Array

DOA estimation is widely used in communications,radar,sonar exploration,and satellite navigation.When the signal is sent out,the receiving array needs to estimate the direction of the signal in noisy environment,so it is very important to accurately estimate the angle of the signal.The research and analysis of two-dimensional DOA estimation algorithm shows that the two dimensional DOA estimation algorithm based on ESPRIT in dual parallel linear array is flawed,and the estimation error is too high even when the signal pitch angle approaches a special angle of 90 degrees.Therefore,the original algorithm needs to be studied and improved to ensure that the improved algorithm overcomes the problem of pitch angle failure and improves the estimation performance of two-dimensional angle of signal.This thesis mainly focuses on the accurate location of two dimensional direction of arrival of signals and makes an in-depth study of the algorithm.The specific work of this paper is as follows:(1).This paper briefly summarizes the theoretical background of array signal processing and the basic principle of DOA estimation,and studies and analyses the estimation performance of various DOA estimation algorithms.(2).In this paper,a two-dimensional DOA estimation algorithm based on ESPRIT for twolayer three-line array is proposed.On the basis of the two-layer array model,the azimuth and elevation of the signal are estimated by two-dimensional ESPRIT algorithm.Compared with the ESPRIT algorithm adopted by the traditional double parallel linear array,the improved algorithm avoids the joint estimation of azimuth and elevation angle of signal in the processing of data receiving matrix,but estimates the elevation angle of signal separately,so as to reduce the probability of DOA estimation method failure when the elevation angle approaches 90 degrees.The improved algorithm also achieves fast matching of azimuth and elevation parameters of signal signals.It does not need eigenvalue decomposition of matrices involving azimuth and elevation parameters at the same time.It only needs eigenvalue decomposition of one of the matrices,and then uses the same characteristic vectors of eigenvalue decomposition of the two matrices to solve the eigenvalues of the other matrix.The algorithm greatly simplifies the operation process and reduces the computational complexity.(3).In this paper,we have verified the problem of estimating the failure of two dimensional DOA estimation algorithm based on ESPRIT in double parallel linear array at the special two-dimensional angle of 90 degrees when the signal pitch angle is in the simulation.Simulation results show that the 2-D DOA estimation algorithm based on ESPRIT in twotier three wire array has no estimation failure when the signal pitch angle is at 90 degree,which overcomes the defect of the estimation of pitch angle failure.The performance of the improved algorithm and the original algorithm is compared and analyzed.From the analysis of four factors,such as SNR,snapshot number,signal azimuth and pitch angle,it is verified that the improved algorithm has higher resolution.When the signal pitch angle is greater than 80 degrees,the root mean square error RMSE of the improved algorithm decreases from 1 to 0.2 degrees,thus improving the estimation accuracy of the algorithm.The main purpose of the research and improvement algorithm is to overcome the defects caused by the ESPRIT algorithm of the traditional two-level parallel linear array.When the pitch angle of the signal is close to 90 degrees,the estimation of elevation is invalid.The simulation results show that the resolution of the algorithm is higher than that of the original algorithm at 90 degree pitch angle.