Research On DOA Estimation Based On Communication And Radar Integrated System Array

The principles of the communication system and the radar system are similar,and with the development of science and technology,the structure of the two is gradually similar,so the integration of communication radar has gradually become a hot spot for scholars.With the development of 5G large-scale array technology,high-resolution methods for obtaining targets using array signal processing have made target detection based on communication base stations possible.Radar processing algorithms are used to process the OFDM(Orthgonal Frequency Division Multiplexing)signals received by these base stations to obtain information such as target speed,distance,and bearing.Target detection is to detect the distance,speed and azimuth of the target,and this paper mainly studies the azimuth detection of the target,and uses the basic DOA(Direction of Arrival)estimation algorithm to perform the echo signal received by the large-scale array of communication base stations.The target angle is estimated to obtain the position information of the target.The main research contents of this article are as follows:Firstly,the similarity and difference between the communication system and the radar system are analyzed,and the principle of OFDM signals commonly used in communication base stations is further analyzed to study the selection of cyclic prefix length in OFDM signals.The paper presents an array DOA observation model for uniformly distributed base stations,studies MUSIC,ESPRIT and cascaded MUSIC algorithms for uniform linear arrays and uniform area arrays,and uses the measured data of communication base stations to estimate the DOA of the target.The experiment of the measured data shows that the DOA estimation algorithm can be used to estimate the target orientation of the OFDM echo signal received by the communication base station,which verifies the feasibility of the target orientation estimation based on the communication base station.Then,for sparsely arranged arrays,this paper gives DOA observation models of nested linear arrays and coprime linear arrays,and studies the estimation methods of nested linear array arrival angles and mutual prime linear arrays based on spatial smoothing MUSIC and ESPRIT.Experimental results show that,compared with uniform linear arrays,both nested linear arrays and coprime linear arrays have good anti-noise performance,the angle of arrival estimation performance is more excellent,and more degrees of freedom can be obtained.Furthermore,for the problem of high computational complexity of spatial smoothing algorithms,a Toeplitz matrix reconstruction algorithm is introduced.To maintain the same angle estimation accuracy,the Toeplitz matrix reconstruction algorithm reduces the computational complexity compared to traditional methods.Finally,this paper studies the nested area array and the coprime area array in the sparse area array,gives the DOA observation model of the nested area array and the coprime area array,and gives the spatial smoothing method.Under the condition of the same array element,simulation experiments show that the DOA estimation performance of the nested area array and the sparse area array is better than the uniform area array.At the same time,as the number of array elements increases,the angle of arrival of the nested area array and the coprime area array It is estimated that the better the performance,and the higher the degree of freedom.