SAR目标检测识别理论与关键技术-IEEEGRSS.ppt

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1、COMPARISONOFGEOMETRY-BASEDDOPPLERAMBIGUITYRESOLVERINSQUINTSAR&WenchaoLiUniversityofElectronicScienceandTechnologyofChinaANINDIRECTDOPPLERRATEESTIMATIONSCHEMEOFSARINLOW-CONTRASTSCENEIntroductionSyntheticApertureRadar(SAR)Animportantremotesensingtool.MonostaticSARBistaticSARStripmapSA

2、RScanSARSpotlightSARSide-lookingSARSquint-lookingSAR……IntroductionSquintSARGeometrymodelSquintangleIntroductionSquintSARRangeHistory：ThelineartermisrangewalkThequadratictermisrangecurvatureIntroductionDopplercentroid()Dopplerrate()Afterrangewalkcorrection,theazimuthdatacanbemodeleda

3、salinearfrequencymodulated(LFM)signal,SignalmodelIntroductionInprinciple,itispossibletocomputeDopplerparameterfrompriorinformationprovidedbyGPS/INS,butmeasurementuncertaintiesontheinformationwilllimittheaccuracy.IntroductionAnincorrectDopplercentroidalossofSNR;anincreaseintheazimuth

4、ambiguitylevel;ashiftinthelocationofthetarget;…...IncorrectDopplerrateCorrectDopplerrateAnincorrectDopplerratewouldblurtheimage.IntroductionTherefore,DopplerparameterEstimationfromechodataisanessentialprocedureforhighqualitySARprocessingDopplercentroidestimation(ResolveDopplercentro

5、idambiguity)DopplercentroidestimationAsazimuthdataaresampledbypulserepetitionfrequency(PRF),thereisalwaysDopplercentroidambiguity,andthebiggerthesquintangleis,themoreseriousthedopplerambiguitywillbe.Dopplercentroidisusuallyexpressedintwoparts:thebasebandDopplercentroidandDopplerambi

6、guitynumber.DopplercentroidestimationMultiplePRFWavelengthdiversityalgorithm(WDA)Multilookalgorithms(MLCC,MLBF)Geometry-basedalgorithmsGeometry-basedalgorithmsTherelationshipbetweenDopplercentroidandrangewalkslope,Sincethismethodisbasedonthegeometriccharacteristicsoftherangecompress

7、eddata,itisnamedasageometry-basedDopplerambiguityresolver.ThenDopplercentroidcanbecomputedviaestimatingtherangewalkslope.ConventionalRadontransformschemeRadontransform:Awell-knowntoolfordetectingslope.Itintegratesintensityalongeverypossibledirectionintheimageandmapsthisinformationin

8、toafeaturespace.Iti