Research On Array Direction Finding Technology For Noncircular Signals

As the generation,development and application of array antenna,array signal processing has become an important area of signal processing research.It has also been widely used in the fields of radar,wireless communication,astronomy,seismic prospecting,biomedicine and so on.Signals can be divided into non-circular and circular signals in terms of their statistics characteristics,and can also be divided into far-field signals and near-field signals according to the distance between the signal sources and the receiving array.In practical systems,the receiving array would receive circular and noncircular mixed signals,or the far-field and near-field mixed noncircular signals.Therefore,it is important to study the DOA estimation algorithms based on the circular and noncircular mixed signals or the far-field and near-field mixed noncircular signals.This paper concentrates on these two key issues and proposes corresponding solutions and algorithms.For the circular and non-circular mixed signals are incident on uniform rectangular array,based on the principle of rank reduced and Root MUSIC method,we propose a 2-D finding algorithm for mixture of circular and non-circular sources.The proposed method can estimate the direction of arrival effectively,and distinguish these two kinds of signals.The proposed method can also automatically pair the 2-D DOAs.Besides,the theoretical error of the proposed method is analyzed,which provides the performance evaluation criteria for the algorithm.For the far-field and near-field mixed noncircular signals are incident on the symmetrical uniform linear array,based on the differences of signal models,the paper gives a localization algorithm for mixed far-field and near-field noncircular signals.Firstly,the model of mixed signals in far field and near field is established.Then the estimators of two signals are constructed respectively,thus the problem of estimating and distinguishing the mixed signals can be solved.Due to the proposed algorithm takes full advantage of the noncircular information of signals,the performance of parameter estimation is superior to other algorithms,and the conclusion has been provided by the simulation results.