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第38卷第4期光电工程Vol.38,No.42011年4月Opto-ElectronicEngineeringApril,2011文章编号:1003-501X(2011)04-0095-08Raw-echo-basedChannelBalancingAlgorithmforSAR-GMTIQIANJiang1,LÜXiao-lei1,LILiang-hai2,YANGMin3,XINGMeng-dao1(1.NationalLabofRadarSignalProcessing,XidianUniversity,Xi’an710071,China;2.The704thInstitute,ChinaAerospaceScienceandTechnologyCorporation,Beijing100076,China;3.TheMilitaryRepresentativeOfficeoftheGeneralEquipmentDepartmentinHuaCountry,Xi’an710068,China)Abstract:Thechannelmismatchproblemwasinvestigatedinmulti-apertureSyntheticApertureRadar(SAR).Achannelbalancingtechniquebasedonthetwo-stagefiltersinthedifferentrawdatadomainswaspresented.TheamplitudeandphasefilterintherangeDopplerdomaincorrespondstotheantennabeampatterndifference,andthefilterintherangefrequencyazimuthtimedomaincorrespondstothefrequencyresponsedifference.Inthefirststagefilteringprocess,weconstructedanadaptivefilterintheregionwithhighercoherence,andanon-adaptiveoneinthenoisedominatedregiontoremovethedeterministicdifferencebetweenchannels.Inthesecondstagefilteringprocess,thenoisewasremovedandonlythetargetsignatureswereleft.Thefeasibilityofthechannelbalancingalgorithmcarriedoutintherawdatadomainisdemonstratedwiththemeasuredairbornedata.Keywords:channelbalancing;channelmismatcherror;syntheticapertureradargroundmovingtargetindicator(SAR-GMTI);adaptivefilterCLCnumber:TN957.51Documentcode:Adoi:10.3969/j.issn.1003-501X.2011.04.017基于原始数据的SAR-GMTI通道均衡方法钱江1,吕孝雷1,李凉海2,杨敏3,邢孟道1(1.西安电子科技大学雷达信号处理国家重点实验室,西安710071;2.中国航天科技集团第七〇四所,北京100076;3.总装驻华县地区军代室,西安710068)摘要:本文研究多孔径合成孔径雷达(SAR)通道间的失配问题,提出了一种在两个SAR原始数据域进行两步滤波的通道均衡方法。针对天线波束方向图差异进行距离多普勒域上的幅相滤波,在距离频域方位时域进行的幅相滤波针对的是频率响应差异。在第一步滤波中,为消除通道间的确定性差异,对高相干性区域构造一个自适应滤波器,对噪声区域则采用非自适应滤波。经过第二步滤波后,噪声被滤除,剩余就是运动目标信号。机载实测数据处理验证了原始数据域通道均衡方法的可行性。关键词:通道均衡;通道失配误差;SAR地面运动目标检测(SAR-GMTI);自适应滤波器0IntroductionSyntheticApertureRadar(SAR)canobtainthehighresolutionimageofthegroundscene,andtheGroundMovingTargetIndication(GMTI)modewhichisthemaintaskinair-to-groundtheaterreconnaissancecanacquirethemovingtargetinformation.Itisdesirabletofindthemovingtargetsattheslowspeedsubmergedinthebackgroundclutter.ThewidelyusedcluttersuppressionmethodsaretheSpaceTimeAdaptiveProcessing收稿日期:2010-09-26;收到修改稿日期:2011-01-17基金项目:自然科学基金重大资助项目(60890072);武器装备预研基金项目(9140A21020609DZ01)作者简介:钱江(1980-),男(汉族),浙江嵊州人。博士研究生,主要研究合成孔径雷达成像及运动目标检测。E-mail:7anjiang@gmail.com。光电工程2011年4月96(STAP)[1-3]andtheJointSubspaceProjection(JSP)[4],whichistherecentlydevelopedandrequirestheknowledgeofvelocityinformationofthemovingtargets.Anewmethodproposedin[5]isbasedoneigendecompositionofsamplecovariancematrix,whichistime-consumingsinceanimageblockshouldbeusedassamplestocomputeametricforeachpixel.Thesimpleandwell-knownapproachtothisproblemisDisplacedPhaseCenterAntenna(DPCA)technique.DPCAexploitstheechodifferencesamongchannels.Severalchannelsarealignedalongtheflightdirectionofplatform.Theoretically,staticclutterintheechooftheforechannelcanbecancelledbytheaftoneafterseveralpulseswhenthephasecentersoftwochannelsareoverlappedandthemovingtargetsareleftintheresidualsignals.Detectionbasedonamplitudeiscarriedoutinthedifferenceofcompleximage,andthepositioninformationoftargetscanbedirectlyobtained,andthevelocitycanbederivedfromtheinterferometricphasebetweentwodifferenceimages.Theaboveanalysisisbasedontheidealidentityofamplitudeandphaseamongchannels.Inpractice,thechannelsareimpossibletobeidentical,whichwillinfluencecluttersuppressionaswellastheinterferometricphase.Themismatcherrorsamongthechannelsincludethebaselinevariationinducedbytheplatformmotionerrors,antennabeampatterndifferenceandfrequencyresponsedifference.Alltheaboveerrorswereanalyzedin[6]andthecorrespondingcompensationstrategieswereproposed.Differentfrom[6]whichwasprocessedintheSARimagedomain,theproposedchannelbalancingstrategyiscarriedoutintherawdatadomain,whichleadstothedifferentfilteringmethods.Thechannelbalancingstrategybasedonrawechodomainiscompletedinsub-aperture,soitismorenaturalandrobusttomotionerrors.WhiletheSARimagedomainbasedstrategyiscompletedinfull-aperture,wherethemotioncompensationwillaffectthechannelbalancingresulttosomeextent.Themotion-inducederrorscanbecompensatedbythemotioncompensationalgorithm.Toremovetheantennabeampatternandfrequencyresponsedifference,firstly,removethedeterministicamplitudeandphaseerrorsdeterminedbythesystemwiththeStage1filter,whichcomposesanadaptivefilterfortheareaswithhighcoherenceandanon-adaptiveonefortheareawithnoisedominated;secondly,removethenoiseintheresidualsignaturethroughtheStage2filter.Bothoftwostagesarefinishedintherawdatadomain.Thepaperisorganizedasfollows.InSection1,channelmismatcherrorsareanalyzed.InSection2,atechniqueconsistingoftwostagesandtwoplanesforamplitudeandphasecorrectionsisproposedtocompensatetheerrorsmentionedinSection1.InSection3,performanceisanalyzedandverifiedbyexperimentalresults.Section4concludesthepaper.1ChannelMismatchErrorsAnalysisInthissection,weanalyzethemainsourcesofchannelmismatcherrorsasfollows:1)Motion-inducedErrorIntheidealcase,theDPCA-antennasarealignedwiththemovingtra
本文标题:基于原始数据的SAR_GMTI通道均衡方法_英文_
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