简介：ConventionalSyntheticApertureRadar(SAR)systemscannotobtainhigh-resolutionandwide-swathilluminationareaduetothewell-knownminimumantennaareaconstraint.SinglePhaseCenterMultiBeam(SPCMB)techniquecanovercomethislimitationbyaddingspatialsamplingthroughmultiplereceiversinazimuthdirection.Unfortunately,thisapproachwillleadtoanincreaseofazimuthambiguities(interbeamambiguities),becauseeachreceivebeam’smainlobeoverlapswiththeotherones’sidelobes.ThispaperprovesthatthefrontpartofSPCMBSARsystemscanbeconsideredtobeahybridfilterbank.Therefore,theazimuthsignalcanbereconstructedandtheinterbeamam-biguitiescanbeeffectivelysuppressedbyawell-designedhybridfilterbank.

简介：定位精度是合成孔径雷达（SAR）系统的一项重要指标。文中首先从星载SAR图像的4定位原理出发,提出了距离-多普勒定位法的定位条件,并通过直接法得出了定位模型然后对星载SAR的定位误差进行了详细分析和仿真计算,并对仿真结果进行了归纳总结。仿真结果表明,影响定位精度的主要因素是斜距测量误差、目标高度误差、平台星历（位置和速度）误差。而多普勒频率测量误差对定位精度影响则可忽略不计。

简介：ToperformthegroundtestofaspaceborneSyntheticApertureRadar(SAR)system,anechosimulatorwiththecharacteristicsofmultimode,multi-assemblage,andrealtimeisproposedinthispaper.Ahardwareplatformofthereal-timeechosimulatorbasedontheVPXbusisdesigned.Withthisplatform,real-timemulti-pointechogenerationandscenariotargetsechogenerationcanbeachievedbythereal-timesignalprocessinginFieldProgrammableGateArray(FPGA),utilizingtheparameterscalculatedbytheindustrycomputers.Furthermore,thisplatformcanoutputdifferentsignalsifitisexpandedtomulti-channels,makingitpossiblefortheassignmentofechogenerationandtestindifferentspaceborneSARmodes.ThetestresultswiththeactualSARsystemshowthatthisplatformcansatisfythesystemrequirementsandisnowusedinpractice.

简介：Fusionofsyntheticapertureradar(SAR)andforwardlookinginfrared(FLIR)imagesisanimportantsubjectforaerospaceandsensorsurveillance.ThispaperpresentsaschemetoachieveanaturalcolorimagebasedonthecontoursfeatureofSARandthetargetregionfeatureofFLIRsothattheoverallscenerecognitionandsituationalawarenesscanbeimproved.TheSARandFLIRimagesarefirstdecomposedintosteerablepyramids,andthecontourmapsintheSARimageandtheregionmapsintheFLIRimagearecalculated.Thecontourandregionfeaturesarefusedateachlevelofthesteerablepyramids.Acolorimageisthenformedbytransferringdaytimecolortothemonochromicimagebyusingthenaturalcolortransfertechnique.ExperimentalresultsshowthattheproposedmethodiseffectiveinprovidingacolorfusionofSARandFLIRimages.

简介：AnewfilteringmethodforSARdatade-noisingusingwaveletsupportvectorregression(WSVR)isdeveloped.OnthebasisofthegreyscaledistributioncharacterofSARimagery,thelogarithmicSARimageasanoisepollutedsignalistakenandthenoisemodelassumptioninlogarithmicdomainwithGaussiannoiseandimpactnoiseisproposed.Basedonthebetterperformanceofsupportvectorregression(SVR)forcomplexsignalapproximationandthewaveletforsignaldetailexpression,thewaveletkernelfunctionischosenassupportvectorkernelfunction.ThenthelogarithmicSARimageisregressedwithWSVR.Furthermoretheregressiondistanceisusedasajudgmentindexofthenoisetype.Accordingtothejudgmentofnoisetypeeverypixelcanbeadaptivelyde-noisedwithdifferentfilters.Throughanapproximationexperimentforaone-dimensionalcomplexsignal,thefeasibilityofSARdataregressionbasedonWSVRisconfirmed.AfterwardtheSARimageistreatedasatwo-dimensionalcontinuoussignalandfilteredbyanSVRwithwaveletkernelfunction.Theresultsshowthatthemethodproposedherereducestheradarspecklenoiseeffectivelywhilemaintainingedgefeaturesanddetailswell.

简介：对ATI技术进行改进，提出了一种机栽双通道SAR加权ATI地面慢速运动目标检测方法。该方法将DPCA技术和ATI技术的优点结合起来，利用DPCA技术得到加权值对ATI干涉结果进行加权处理，提出了一种新的动目标检测方法。计算机仿真结果表明，该改进方法与ATI方法相比能够有效减少虚假目标的数目，并能够检测到弱目标；与DPCA方法相比，它能够检测到DPCA方法由于对消过大而无法检测到的速度更慢的目标。

简介：提出了一种基于压缩感知（CS,compressivesensing）的SAR对多舰船目标的成像算法。通过将多舰船目标成像转换为在某种基下具有稀疏表示的信号重建问题,从而满足CS理论对信号恢复重构的要求,获得比传统成像方法更高的方位分辨率。实测数据的处理验证了该算法的有效性。

简介：基于SAR图像的舰船目标自动检测是海洋监视应用的重要方面,但随着SAR成像能力和图像分辨率的提高,传统的CFAR检测方法已不能满足舰船目标自动检测的要求。针对中高分辨率SAR图像中舰船目标自动检测问题,提出一种基于像素筛选G0分布的SAR图像舰船目标快速检测方法,该方法首先根据像素灰度值出现频率选取阈值对杂波像素进行筛选,然后通过抽样定理对图像进行降分辨率处理,最后再在经过像素筛选的降分辨率图像中实现基于G0分布的自适应CFAR检测。NASA/JPLAIR-SAR实测数据的实验结果表明,该方法不仅能有效减少中高分辨率SAR图像舰船目标自动检测的虚警,而且能显著提高检测效率。

简介：天线外定标是实现星载SAR天线方向图在轨测试的主要手段。天线方向图的准确测量，对星载SAR图像的应用具有重要作用。分布目标辐射定标在星载SAR天线方向图测试中受到广泛重视。亚马逊热带雨林的后向散射系数呈现大面积的均匀性和稳定性，故成为分布目标定标最主要的定标场。该文在分布目标定标原理的基础上，对基于亚马逊热带雨林的星载SAR天线方向图测量算法进行了研究，提出了采用K．Pearson统计量非参数假设检验的一致性处理算法，并采用Levenberg-Marquard算法（LM算法）估计俯仰向天线方向图模型参数。仿真数据验证了算法的可靠性和准确性。

简介：Movingshipsproduceasetofwavesof"V'patternontheocean.ThesewavescanoftenbeseenbySyntheticApertureRadar(SAR).Thedetectionofthesewakescanprovideimportantinformationforsurveillanceofshipping,suchasshiptravelingdirectionandspeed.AnovelapproachtothedetectionofshipwakesinSARimagesbasedonfrequencydomainisprovidedinthisletter.ComparedwithtraditionalRadon-basedapproaches,computationisreducedby20%-40%withoutlosingnearlyanyofdetectionperformance.ThetestingresultsusingrealdataandsimulationofsyntheticSARimagestestthealgorithm'sfeasibilityandrobustness.

简介：基于SAR成像中散射点模型的参数估计,提出了一种适用于经过距离走动校正之后,在方位向上仍存在两次及两次以上相位误差的动目标的自聚焦算法.该方法在方位数据域上结合离散多项式相位变换(DPT)方法和最小二乘估计法估计相位误差,用CLEAN算法估计散射点参数,并通过交替迭代运算,可以较少的距离单元实现较为精确的误差补偿,因而运算量小.经过实测数据验证,该算法获得了理想的自聚焦.

简介：

简介：Inthispaper,inordertoimprovetheaccuracyoftheSyntheticApertureRadar(SAR)satelliteattitudeusingGlobalPositioningSystem(GPS)wide-bandcarrierphase,theSARsatelliteattitudekinematicvectorandKalmanfilterareintroduced.IntroducingthestatevariablefunctionofGPSattitudedeterminationalgorithminSARsatellitebymeansofkinematicvectoranddescribingtheobservationfunctionbytheGPSwide-bandcarrierphase,thepaperusestheKalmanfilteralgorithmtoobtiantheattitudevariablesofSARsatellite.ComparedthesimulationresultsofKalmanfilteralgorithmwiththeleastsquarealgorithmandexplicitsolution,itisindicatedthattheKalmanfilteralgorithmisthebest.

简介：针对SAR影像进行水上桥梁目标检测问题,提出了一种纹理特征与关联特征相结合的方法。该方法首先通过去噪及增强预处理改善图像质量,并采用阈值分割方法快速提取初始目标;然后使用灰度共生矩阵对目标及其周边背景纹理进行差异对比分析,从而去除虚警目标。实验结果表明,该方法能够准确地检测出水上桥梁目标。

简介：Inthespaceborne/airborneforward-lookingbistaticsyntheticapertureradar(SA-FBSAR),duetothesystemplatforms'remarkablevelocitydifferenceandtheforward-lookingmode,therangecellmigration(RCM)notonlydependsonthetarget'stwodimensionallocation,butalsovarieswiththerangelocationnonlinearly.Andthenonlinearityisnotjusttheslightdeviationfromthelinearpart,butexhibitsevidentnonlineardepartureintheRCMtrajectory.IftheRCMisnotproperlycorrected,nonlinearimagedistortionswouldoccur.BasedontheRCMmodel,amodifiedtwo-stepRCMcompensation(RCMC)methodforSA-FBSARisproposed.Inthismethod,firstlytheazimuth-dependentRCMiscompensatedbythescalingFouriertransformandthephasemultiplication.Andthentherange-dependentRCMisremovedthroughinterpolation.TheeffectivenessoftheproposedRCMCmethodisverifiedbythesimulationresultsofbothpointscatterersandareatargets.

简介：首先建立了机栽双基地SAR的几何模型、距离历程和回波模型。接着简要总结了双基地SAR成像的算法思路。通过理论推导改进了单基地BP成像算法使其适合于双基地情况，并探讨了改进的快速BP算法。最后用点目标和面目标仿真验证了双基地下BP算法的有效性和适用性，并与RD算法进行了性能的比较。

简介：文中重点介绍ENVISAT和RADARSAT-2卫星数据对2010年海水养殖区监视应用情况，研究养殖区的分类和估算面积，为今后的海事部门开展碍航养殖清理提供参考和经验积累。

简介：ToretrievewindfieldfromSARimages,thedevelopmentforsurfacewindfieldretrievalfromSARimagesbasedontheimprovementofnewinversionmodelispresent.GeophysicalModelFunctions(GMFs)havebeenwidelyappliedforwindfieldretrievalfromSARimages.AmongthemCMOD4hasagoodperformanceunderlowandmoderatewindconditions.AlthoughCMOD5isdevelopedrecentlywithamorefundamentalbasis,ithasambiguityofwindspeedandashapegradientofnormalizedradarcrosssectionunderlowwindspeedcondition.ThisstudyproposesamethodofwindfieldretrievalfromSARimagebycombiningCMOD5andCMOD4FiveVV-polarisationRADARSAT2SARimagesareimplementedforvalidationandtheretrievalresultsbyacombinationmethod(CMOD5andCMOD4)togetherwithCMOD4GMFarecomparedwithQuikSCATwinddata.Theroot-mean-squareerror(RMSE)ofwindspeedis0.75ms-1withcorrelationcoefficient0.84usingthecombinationmethodandtheRMSEofwindspeedis1.01ms-1withcorrelationcoefficient0.72usingCMOD4GMFaloneforthosecases.TheproposedmethodcanbeappliedtoSARimageforavoidingtheinternaldefectinCMOD5underlowwindspeedcondition.

简介：在地基SAR（GB-SAR）差分干涉测量中，大气扰动影响是其测量精度误差的重要来源。提出了一种基于角反射器的地基SAR差分干涉测量大气扰动误差校正方法；该方法利用角反射器作为稳定控制点，根据其干涉相位的变化情况来分析观测区域大气扰动影响，从而实现对其扰动误差的校正。为了检验该校正方法的实用性，进行了三面角反射器外场形变测量中大气扰动误差校正实验，并将其校正结果与基于气象参数补偿法的校正结果进行了对比。结果表明，该校正方法具有很好的可靠性和精确性。

简介：完成一个14位的连续近似收款机analog-to-digital变换器(SAR模数转换器)的一种错误修正技术被建议。一个悦耳的裂口电容器被设计消除寄生电容器引起的失配。进程失配引起的电容器数组的线性错误被能改进采样率的一个新奇刻度电容器数组校准。双比较仪的拓扑学保证ADC的速度和精确。模拟结果证明在刻度以后的SAR模数转换器在500kilosamples/s完成83.07dBSNDR和13.5小点ENOB。