简介:Afocusingtransformbasedminimumvariancemethod(FTMV)isproposedforestimatingtheazimuthanglesofwidebandsignals.TheestimationerrorofDirectionofArrival(DOA)inthetraditionalMinimumVariance(MV)methodduringthearraydirectionchangingwiththeshipcanbeeliminatedbyfocusingthesamplecovariancematricesinwidebandontoasinglenarrowband,andaccumulatingthebeamformeroutputsonazimuth.Then,theazimuthanglesofsignalscanbeestimatedaccurately.ExperimentalresultsshowthattheFTMVmethodismoreefficientandrobustthantheMVmethodinthiscase.
简介:ConventionalSyntheticApertureRadar(SAR)systemscannotobtainhigh-resolutionandwide-swathilluminationareaduetothewell-knownminimumantennaareaconstraint.SinglePhaseCenterMultiBeam(SPCMB)techniquecanovercomethislimitationbyaddingspatialsamplingthroughmultiplereceiversinazimuthdirection.Unfortunately,thisapproachwillleadtoanincreaseofazimuthambiguities(interbeamambiguities),becauseeachreceivebeam’smainlobeoverlapswiththeotherones’sidelobes.ThispaperprovesthatthefrontpartofSPCMBSARsystemscanbeconsideredtobeahybridfilterbank.Therefore,theazimuthsignalcanbereconstructedandtheinterbeamam-biguitiescanbeeffectivelysuppressedbyawell-designedhybridfilterbank.
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简介:Toaimattheproblemthatthehorizontaldirectivityindexofthevectorhydrophoneverticalarrayisnothigherthanthatofavectorhydrophone,thehigh-resolutionazimuthestimationalgorithmbasedonthedatafusionmethodwaspresented.TheproposedalgorithmfirstemploysMUSICalgorithmtoestimatetheazimuthofeachdividedsub-bandsignal,andthentheestimatedazimuthsofmultiplehydrophonesareprocessedbyusingthedatafusiontechnique.Thehigh-resolutionestimatedresultisachievedfinallybyadoptingtheweightedhistogramstatisticsmethod.TheresultsofthesimulationandseatrialsindicatedthattheproposedalgorithmhasbetterazimuthestimationperformancethanMUSICalgorithmofasinglevectorhydrophoneandthedatafusiontechniquebasedontheacousticenergyfluxmethod.Thebetterperformanceisreflectedintheaspectsoftheestimationprecision,theprobabilityofcorrectestimation,thecapabilitytodistinguishmulti-objectsandtheinhibitionofthenoisesub-bands.
简介:TheDirectionsofArrivals(DOAs),speedsanddistancesoftargetsareallrequiredforarraysignalprocessing.Basedontheperiodicphaseshiftofcoherentpulsesequencewaveform,anewestimationofmulti-targets'2-Dimentional(2-D)DOAangle,Dopplerfrequencyshiftandrelativetime-delayisproposed.Basedonavirtualsensorarrayconstructedbypulsecumulating,theestimationsofazimuth,elevation,Doppierfrequencyshiftandtime-delaycanbeobtainedsimultaneously,andtheleastnumberofpulsescouldbetwo.Thismethodiscomputationallyefficienteveninheaviernoisedenvironment,andallestimationsareautomaticallypairedincalculationprocesswithnospectrumsearching.Furthermore,thisalgorithmcanbeusedtoanyplanesensorarrayanddealwithmanytargetsatthesametimeonlybyfewsensors.Thetargetsnumberthatcandealwithsimultaneouslyisseveraltimestothesensornumber,whichistheupperlimitfornormalalgorithmssuchasESPRITandMUSIC.Thesecharacteristicswouldbeveryuseful,especially,foraerialsystems.Simulationsdemonstratethecapabilitiesofthismethodefficiently.