二次雷达 基本原理课件.ppt

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1、二次雷达（SSR）中国民航大学电子信息工程学院outlineSSRintroductionMODEA/CMODES2outlineSSRintroductionMODEA/CMODES3LimitationsofPSR(WhyweneedSSR?)Targetsthataretoosmall,orarebuiltofapoorradarreflectingmaterialorhaveapooraspectmaynotbedetectedTargetscannotbeidentifieddirectly(IFFintheWW2)Radarenergysuffe

2、rsfromattenuation(losses)bothonthepathouttothetargetandonthereturnpathofthereflectionsTheroleoftheSSRistocomplementthePSR4RadarAntennaGroundRadarDisplayTransmitterReceiverRadarAntennaGroundRadarDisplayTransmitterReceiverModeA/CXPDRInterrogationReplyPlaneIdentificationPlaneAltitudeR

3、adarAntennaGroundRadarDisplayTransmitterReceiverSSR：SecondarySurveillanceRadarSSRisaradar systemusedinATC/CNSthatnotonlydetectsandmeasuresthepositionofaircrafti.e.rangeandbearing,butalsorequestsadditionalinformationfromtheaircraftitselfsuchasitsidentityandaltitude.Unlikeprimaryrada

4、rsystemsthatmeasureonlytherangeandbearingoftargetsbydetectingreflectedradiosignals,SSRreliesontargetsequippedwitharadartransponder,thatrepliestoeachinterrogationsignalbytransmittingaresponsecontainingencodeddata.SSRisbasedonthemilitary identificationfriendorfoe (IFF)technologyorigi

5、nallydevelopedduring WorldWarII,thereforethetwosystemsarestillcompatible.Monopulsesecondarysurveillanceradar (MSSR), TCAS and ADS-B aresimilarmodernmethodsofsecondarysurveillance.8PSRvsSSR9SSRantenna10SSRcharactersSSRisnotatrueradarsystembutatwowaycommunicationssystembetweenaninter

6、rogatoronthegroundandatransponderontheaircraft.HoweverSSRisverysimilarinoperationtoconventionalradarandsuffersfrommanyofthesameproblemsandlimitations.Mostcommercialaircraftarerequiredtobefittedwiththisequipmentfortransitthroughcontrolledairspace.11OperationofaSecondaryRadar12SSRwor

7、kflowSSRisconstitutedbyoneground-basedtransmitterandreceiver,calledinterrogator,andoneairbornetransmitterandreceiver,referredtoastheATCtransponder,orsimply‘transponder’.Theinterrogatortransmits(1030MHz)pulsepairs,thereceiverwithintheinterrogator’sbeamreceivesthesepulsesanddecodesth

8、em.Thetransponderthenrespo