简介:GEO卫星在导航系统中发挥着基本导航、增强和转发等三大功能。针对北斗系统GEO卫星的特殊性和兼容性,对北斗GEO卫星播发的D2导航电文的特点进行了分析,利用GEO的静地特性在基带信号处理中应用数学思想提出了基于二次函数逼近的快速牵引,推导了GEO卫星位置速度的计算公式,提出了基于模糊控制的GEO伪距测量算法,提高了信号处理通道的通用性和兼容性。对相关算法和策略在基于DSP+FPGA的软件接收机中利用实际信号进行了验证,在省略精捕获时间的情况下实现了50Hz以下的多普勒频移精度,伪距测量方法的通用性节省了50%的资源和工作量,相关算法具有良好的实用价值。
简介:Roughsetisanewapproachtouncertaintiesinspatialanalysis.Inthispaper,roughsetsymbolsaresimplifiedandstandardizedintermsofroughinterpretationandspecializedindication.Roughspatialentitiesandtheirtopologicalrelationshipsarealsoproposedinroughspace,thusauniversalintersectedequationisdeveloped,androughmembershipfunctionisfurtherextendedwiththegrayscaleinourcasestudy.Wecompletethreeworks.First,asetofsimplifiedroughsymbolsisadvancedonthebasisofexistingroughsymbols.Second,roughspatialentityisputforwardtostudytherealworldasitis,withoutforcinguncertaintiesintocrispset.Third,roughspatialtopologicalrelationshipsarestudiedbyusingroughmatrixandtheirfigures.Therelationshipsaredividedintothreetypes,crispentityandcrispentity(CC),roughentityandcrispentity(RC),androughentityandroughentity(RR).Auniversalintersectedequationisfurtherproposed.Finally,themaximumandminimummapsofriverthematicclassificationaregeneratedviaroughmembershipfunctionandroughrelationshipsinourcasestudy.
简介:CopyrightSubmissionofamanuscriptimplies:thattheworkdescribedhasnotbeenpublishedbefore(exceptintheformofanabstractoraspartofapub-lishedlecture,review,orthesis);thatitisnotunderconsiderationforpub-licationelsewhere;thatitspublicationhasbeenapprovedbyallco-authors,
简介:Ageo-referenceisaglobalorregionalgeographicalorgeodeticcoor-dinatesystemtowhichsensorsorspatialobjectdataarerelated.Hence,geo-ref-erencingisclosetothewellknownphotogrammetricconceptofexteriororabso-luteorientation,thecommonexecutionofwhichisindirect,viatheuseofgroundcontrolpoint.GPSandINStechnologieshavechangedthesituation,permittingdirectmeasurementofpositionandattitudeparametersandmakingexteriororien-tationfeasiblewithoutgroundcontrolatall,inprinciple.Theanalysisofaccuracyandreliabilityperformancediscloses,however,thatespeciallyINSdoesnotyetmeetthehighdemandsofphotogrammetry.Moreover,controlofsystematicer-rors,theproblemofdatumtransformation,andreliabilityconditionsmaketheuseofsomegroundcontrolpointsstillmandatory,atleastforanyhighperfor-mancegeo-referencing.
简介:Geo-spatialInformationSciencewasfoundedin1998byWuhanUniversity,andisco-publishedworldwidelybySpringer(http://www.springer.com/geography/gis+cartogra-phy/journal/11806)andWuhanUniversity.Itbasicallyprovidesacommunicationplatformfortheworldscientistsandprofessionals,whoseworkismainlyinthe
简介:Urbangeo-environmentmainlyconcernsthoseregardsinandaroundacity,suchasthemovementofearthcrustandearthsurface,conditionsofhydrology,geology,geographyandmeteorology.Therelevantstudiesongeo-disasterreductionandtheinfluencesresultedfromhumanactivitiesonthegeo-environmentareincludedaswell.Itisstressedinthepaperthatgeo-environmentalprotectionandmanagementareofsignificancetothesustainabledevelopmentforChinesecities.
简介:SinceAsiahasgainedmoregeopoliticalandeconomicweight,allpartiesshareastrongsenseofstrategicurgencybecausetheirstrategiesontheAsia-Pacificwilldirectlyaffecttheirfuturedevelopment.PeaceanddevelopmentremainthethemeoftheAsia-PacificandChinashouldpromotemutuallybeneficialdevelopmentintheAsia-Pacific.
简介:Three-dimensional(3D)flowerlikehierarchicalZn2GeO4andMn2+-dopedZn2GeO4microstructureshavebeenpreparedbyafacilehydrothermalapproach.X-Raydiffraction(XRD),fieldemissionscanningelectronmicro-scopy(FESEM),transmissionelectronmicroscopy(TEM)andphotoluminescence(PL)spectrometrywereemployedtocharacterizethesamples.SuchflowerlikehierarchicalZn2GeO4microstructureswithanaveragediameterof3―4μmwerefoundtobeconstructedbyabundantsinglecrystallinenanorodsofabout90nmindiameter.TheluminescentpropertiesofZn2GeO4:xMnphosphorswithdifferentcontentsofMn2+asanactivatorwereinvestigated.TheMn2+-dopedsamplesshowedgreenluminescencecorrespondingtothed-dtransitionofMn2+undertheirradiationofUVlight.Theredshift(from531nmto538nm)inλemwithincreasingMn2+contentwasobservedintheluminescentspectra,whichshouldbeattributedtoaweakcrystalfieldbecauseofthesubstitutionofZn2+byMn2+atadistortedtetrahedrallatticesite.
简介:SupportVectorMachine(SVM)isapowerfulmethodologyforsolvingproblemsinnon-linearclassification,functionestimationanddensityestimation,whichhasalsoledtomanyotherrecentdevelopmentsinkernelbasedmethodsingeneral.Thispaperpresentsahighaccuracyandfault-tolerantSVMforthemobilegeo-locationproblem,whichisanimportantcomponentofpervasivecomputing.Simulationresultsshowitsbasiclocationperformance,andillustrateimpactsofthenumberoftrainingsamplesandtrainingareaontestlocationerror.
简介:“Seminarforhydrocarbondetectionwithcompositegeophysical/geo-chemicaltechniques”,jointlyorganizedbyChinapetroleumExploration&ProductionCompanyandExplorationGeophysicalCommitteeofCGSandsupportedbytheCompositeGeophysical/geo-chemicalDepartementofOrientalGeophysicalCompanyandChinaExploration&DevelopmentResearchInstiute,
简介:Throughanalyzingtheprincipleofdatasharinginthedata-basesystem,thispaperdiscussestheprincipleandmethodforintegratingandsharingGISdatabydataengine,introducesawaytoachievethehighintegrationandsharingofGISdataonthebasisofVCTinVC++,andpro-videsthemethodforunitingVCTintoRDBMSinordertoimplementaspa-tialdatabasewithobject-orienteddatamodel.