Study On Algorithms Of Multidimensional Parameter Joint Estimation For Array Signal

DOA(Direction of Arrival,DOA),frequency and other parameters are the important features of spatial electromagnetic waves,and they are also significant parameters to know the signals carried by spatial electromagnetic waves.So making use of array signal processing technique to estimate DOA,range,frequency and other parameters has been widely used in numerous military and national economic fields,such as radar,sonar,communication,radio astronomy and medical diagnosis.The basic rule for signal processing is to use,extract and recover the useful informations contained in the characteristic of signals.With the developement of communication technique,the signal circumstances become more and more deteriorative,the signal modes keep increasing,the signal density is growing and the ranges of signal frequencis continue to broaden,which makes the density of signal increase greatly in spatial and frequency domain.So it is necessary for frequencies,DOAs and other parameters of multiple signals to have the ability of high precision and high resolution in spatial and frequency domain.This paper focuses on multidimensional parameter joint estimation algorithms in array signal processing.The main work of this paper is as follows:Spatial spectrum estimation is an important research field and one of the basic topics ofarray signal processing.It has been already widely used in some fields,such as radar,sonar,electronic surveillance and seismic exploration.As a part of spatial spectrum,parameter estimation has become a newly hot spot of research in recent years.This is because any single information can not describe the state of the target signals totally,what is more,to be estimated parameters have provided different information of the target signals to us.So parameter estimation becomes an effective method of signal analysis.(1)The research background and significance of multidimensional parameter joint estimation are elaborated.Research status at home and abroad is summarized.The fundamental knowledge of parameter estimation in array signal is introduced.(2)Aiming at that the angle ambiguity problem may exist in electromagnetic environment,this paper proposes a two-stage MUSIC algorithm(referred to as T-MUSIC algorithm).Firstly,the vectors conducted by the anti-diagnoal elemnts of a covariance matrix are utilized to form a number of overlapping subvectors.Making use of these subvectors to give a new covariance matrix and apply MUSIC algorithm to estimate DOAs.Then subsititute the DOA estimations into the former two-dimensional spectrum estimation problem,so we can transform DOA-Range two-dimensional spectral peak search into one-dimensional search related to range to obtain range estimations.This algorithm can not only avoid multidimensional search and high-order statistics,but also resolve angle ambiguity problem.In addition,it also has an advantage on determining estimated parameters automatically.(3)Aiming at joint range,DOA and frequency estimation problem,this paper proposes a multidimensional parameter joint estimation algorithm based on fourth-order cumulant(referred to as JRDF algorithm).Firstly,the two fourth-order cumulant matrixes are conducted by the array output data.Then,define a three-dimensional "information inatrix"which contains all the information of impinging signals by the two cumulant matrixes.The frequencies are estimated by the eigenvalues of the information matrix.And the DOAs and ranges are estimated by the eigenvectors of the information matrix.This algorithm can not only realize parameter match automatically,but also avoid spectrum search and aperture loss.In addition,it has an excellent performance even under low signal-to-noise conditions.