Study On The DOA Estimation Algorithm For Coherent Signals

Array signal processing is an important branch in the field of signal processing and the rapid development and application of radar,communications,sonar,seismic exploration and radio astronomy,as well as biomedical engineering,and many other areas of the national economy and the military sphere in the recent tens of years.Signal processing array signal sensors are installed in a number of different locations of the space sensor arrays,and use this array signal field of space for receiving and processing to obtain time-domain and multi-dimensional information space to detect the signal and extract its parameters.Array signal processing of traditional is based on scalar sensor array studies of the array signal processing In fact;the space electromagnetic signal is vector signal,which comprises total of three electric-field components and three magnetic-field components.If all or part of the electric-field and magnetic-field information can be acquired and exploited,then the performance of the array signal processing will be improved greatly.The electromagnetic vector sensor,which can acquire the complete electric-field components and magnetic-field components,attracts much more attention in recent year.An electromagnetic vector sensor is composed of six spatially co-located,orthogonally oriented and diversely polarized antennas, separately measuring all six electromagnetic-field components of an incident wave-field. The array formed by electromagnetic vectors sensor or trimmed vector sensors called vector sensors array.In other hand,as the vector sensors array can acquire the polarization state of the impinging signals,it is often called polarization-sensitive array(PSA).Compared with the scalar sensors array,the PSA has distinct advantages,such as robust detection,strong interference-suppression and multi-polarization address;when the signals cannot be distinguished in space-field,it can be distinguished well in polarization-field by exploiting their polarization diversity;even the aperture of the PSA is small,the satisfying resolution performance can be achieved.All of these virtues make the PSA widely used in army and civil area.Coherent source is familiar in practice.For example,in the case of multipath or multi-targets,the reflected waves received by radar or sonar are coherent.DOA estimation of coherent source is an important content in radar,communication and sonar.If there is a coherent source,under such circumstances the classic method MUSIC,ESPRIT and the covariance matrix of rank is 1,wave direction to lead to inaccurate or even judge made an error of judgment on the accuracy of the positioning DOA have greater impact,therefore,the Coherent DOA estimates signal is the core of this paper.Classic MUSIC,ESPRIT,are one-dimensional signal DOA estimation methods,which are estimated on the basis of DOA,and the estimated two-dimensional signal DOA estimation study compared one-dimensional signal DOA more to the actual value,for example,in the communications,radar applications.This paper is one-dimensional coherent signal DOA estimation study by the improved TLS-ESPRIT method,and then the one-dimensional coherent signal DOA estimated on the basis of the two-dimensional coherent signal DOA estimates were studied,focusing on uniform Two parallel lines and the structure of L-type array.In this paper,firstly introduces the array signal processing in a number of important knowledge,Electromagnetic vector-sensor model of the received signal were described polarization arrays in detail.And paper introduced nature and concept of matrix algebra signal and cyclostationary.In the third chapter focuses on the one-dimensional signal DOA estimation,the first focused on MUSIC and method of its performance and its respective advantages and disadvantages,then introduced to solve the problem of coherent signal source method of spatial smoothing,based on the idea of Airspace smooth,Because the two-dimensional signal DOA estimates has more practical applications value than the one-dimensional signal DOA estimated,we expends the study to two-dimensional based on the one-dimensional estimated.DOA matrix method based on dual-parallel linear array is a classic 2-D estimation method.It does not need spectral peak searching,and also signals naturally match at the same time.DOA matrix smoothing method can estimate coherent signal source.But these methods can not solve "angle merger" issue. 2-D polarization smoothing algorithm is proposed based on two parallel linear array for coherent cyclostationary signals is proposed in this paper.The algorithm successfully resolves in the case of not losing array aperture.The parameters of estimated process automatically match,and have the abilities of signal choice and noise suppression.L-array is combined by two vertical line arrays and is also a simplified planar array.It has features of simple structure and small redundancy.In this paper,2D smoothing algorithm based on L linear array is put forward after anglicizing and fully using the polarization diversity and cyclostationary characteristics of signals in Chapter 3.The algorithm can correctly estimates 2-D DOA in the case of not losing array aperture,and also has abilities of signal choice and noise suppression.