Research Of DOA And TDOA Estimation Methods Based On Fractional Lower-order Statistics

The main task of this dissertation is DOA estimation in wireless commun-ication system for subscriber.This paper presents a new method which usingfractional lower-order statistics when non-Gaussian noise exists.This method usesthe features of impulsive noise and Sα S process,remedies the shotcoming oftraditional subspace techniques employing both second-order and higher ordermoment which can't be used in impulsive noise environment.In signal processing and many practical applications,people usually uses theGaussian modle to discribe the stochastic signal,which is assumed meet with theGaussian distribution.But in many practical applications,there are manynon-Gaussian signals and noises ,such as radar echo,submarine sound signal,lowfrequency atmosphere noise,some biomedicine signal and so on. α stabledistribution is a very important non-Gaussian random distribution , which hasextensive use in submarine sound signal, atmosphere and biomedicine signalprocessing.In recent years,α stable distribution as well as relevant fractionlow-order statistic are used abroad in submarine sound signal and radar signalprocessing, telecommunication, time delay and medicine signal processing and soon.DOA(Direction-Of-Arrival)estimation is sometimes called directiondiscerning(direction finding),it is used abroad in many fields,such as radar,telecommunication, seismic exploration and medicine,DOA estimation is one ofthe key research in these fileds. Through studing fractional lower-order statistics, discover it is better thanconventional means in some non-gaussian noise inhibitory . these theses mostlyaim at wireless communication system suffer mobile users' doa estimateproblem,this paper present DOA estimation in one dimension ,two dimensionand TDOA estimation by using fractional lower-order statistics.It Resovle theproblem of non-gaussian noise inhibitory,which can not resolve by conventionalmeans.The text contain six chapters,as follows:In chapter one, the text introduces research background, wireless orientmeans and DOA eetimation development history and research actuality.In chapter two, describe matrix foundation knowledge,relate fractionlower-order statistic 'notion and property, for conventional method introduce andtext algorithm set did theoretical preparation.In chapter three, gave out know clearly tradition one dimension doaestimation model,introduce the conventional means, analyses one dimenion DOAbased on fraction lower-order statistic.Present FLOC-SS-MUSIC algorithm.Thesimulation validated the theoretical result.In chapter four,introduce 2-D UCA DOA estimation methed,and present theestimation methed for 2-D UCA DOA based on frsctional lower-orderstatistics,and compose with simple UCA through simulation.In chapter five, introduce know clearly time delay estimation and basicmethod,present the estimation methed multidiameter TDOA based on frsctionallower-order statistics,the simulation validated results.In chapter six, summarizes the whole paper,and show out some questions tobe resovled in the future and next research direction.The main contribution of the paper is listed as fpllow:(1) Study basic knowledge of the arry signal processing ang papers,collect a lot ofliterature about DOA estimation. Put abreast one-step study know clear -lyfraction lower-order statistics and fraction lower-order statistic 'notion.(2) Based on the research work of others, Present FLOC-SS-MUSIC algorith-m .This methed remedies the shortcoming of traditional means can notresovle the cohere source. advance estimated accuracy.The simulationvalidated the theoretical result.(3) Present a new method for 2-d doa fractional lower-order statistics (FLOS)with uniform circular arrays(UCA).This method remedies the shotcoming oftraditional subspace techniques employing both second-order and higher ordermoment which can't be used inimpulsive noise environment.by using thefeature of impulsive noise and Sα S process。This algorithm improve theperformance of traditional 2D-algorithm and extend the scale of the estimationof the doa by using UCA .The simulation validated the theoretical results.(4) look into know clearly TDOA based on fraction lower-order statistic, considermultidiameter condition,present the estimation methed multidiameter TDOAbased on frsctional lower-order statistics. The simulation validated thetheoretical results.