西安工业信号检测与估计SDE_01bRADAR

雷达原理和系统RadarPrinciplesandSystems雷斌13809194497QQ：[e-mail]@163.comSignalDetectionandEstimation信号检测与估值应用介绍Sendthesignal(electromagneticpulse)Receiveback-scatteredradiation(returnsignal)2019/12/16SDE_01introduction32019/12/16SDE_01introduction4TwoBasicRadarTypes•PulseTransmission脉冲雷达•ContinuousWave连续波雷达2019/12/16SDE_01introduction5PulseDiagramPRTPW“Listening”TimePRT=1/PRFCarrierFreq.2019/12/16SDE_01introduction6PulseRadarComponentsSynchronizerTransmitterDisplayUnitReceiverPowerSupplyANT.DuplexerAntennaControl2019/12/16SDE_01introduction7ContinuousWaveRadar•Continualenergytransmission•Separatetransmit/receiveantennas•Relieson“DOPPLERSHIFT”2019/12/16SDE_01introduction8DopplerFrequencyShiftsMotionAway:EchoFrequencyDecreasesMotionTowards:EchoFrequencyIncreases2019/12/16SDE_01introduction9ContinuousWaveRadarComponentsDiscriminatorAMPMixerCWRFOscillatorIndicatorOUTINTransmitterAntennaAntenna2019/12/16SDE_01introduction10PulseVs.ContinuousWavePulseEcho•Singleantenna•Givesrange,usuallyaltitudeaswell•Susceptibletojamming•RangedeterminedbyPWandPRFContinuousWave•Requires2antennae•RangeorAltitudeinfo•HighSNR•Moredifficulttojambuteasilydeceived•Canbetunedtolookforfrequencies2019/12/16SDE_01introduction11RADARWaveModulationAmplitudeModulation–VarytheamplitudeofthecarriersinewaveFrequencyModulation–VarythefrequencyofthecarriersinewavePulse-AmplitudeModulation–VarytheamplitudeofthepulsesPulse-FrequencyModulation–VarytheFrequencyatwhichthepulsesoccur2019/12/16SDE_01introduction12Antenna•TwoBasicPurposes:–RadiatesRadioEnergyinafocusedbeam.–Receivesreflectedechosignalsfromtargetsanddirectsittothereceiver.•MustBe1/2oftheWaveLengthforthemaximumwavelengthemployed•WideBeampatternforSearch,NarrowforTrack2019/12/16SDE_01introduction13AntennaBeamForming2YXRadarBeams(Lobes)雷达波瓣Threedimensionalpatternsoftransmittedenergy.Lookslikeanexpandingdoughnut.RadarBeamWidthTheangularsizeofthebeamintwodimensions.TacticalapplicationdeterminesbeamrequirementDecreasebeamwidth,increaseaccuracyofangularresolution.FieldStrengthMeasuredinWatts/m2xyAB2019/12/16SDE_01introduction16BeamwidthVs.Accuracy波瓣宽度和分辨率BeamwidthvsAccuracyShipAShipB2019/12/16SDE_01introduction17方位角测量DeterminingAzimuthAngularMeasurementAzimuthAngularMeasurementRelativeBearing=Anglefromship抯heading.TrueBearing=Ship抯Heading+RelativeBearingNShip抯HeadingAngleTargetAngle2019/12/16SDE_01introduction18高度测量DeterminingAltitudeDeterminingAltitudeSlantRangeAltitudeAngleofElevationAltitude=slantrangexsin0elevationStackedBeamSPS-48E–Antennaistunedsothateachradarfrequencyleavesthefaceoftheradaratadifferentangle.Thecomputerdetermineswhichfrequencytousedfrompulsetopulsebasedonthepitchandrolloftheship(gyro)andthedesiredanglerequiredoffofthehorizon.2019/12/16SDE_01introduction20ConcentratingRadarEnergyThroughBeamFormation•LinearArrays线阵–Usesfollowingprinciples•Wavesummation(constructiveinterference)•Wavecancellation(destructiveinterference)–Madeupoftwoormoresimple½waveantennae–Example–AegisRadar•Quasi-optical准光学–Usesreflectors反射体and“lenses”透镜toshapethebeam2019/12/16SDE_01introduction21反射体形状ReflectorShape•Paraboloid抛物面-ConicalScanusedforfirecontrol-canbeCWorPulse•OrangePeelParaboliod简化抛物面-UsuallyCWandprimarilyforfirecontrol火控•ParabolicCylinder抛物面柱抛物面-Widesearchbeam-generallylargerandusedforlong-rangesearchapplications-Pulse2019/12/16SDE_01introduction22波导WaveGuides•Usedasamediumforhighenergyshielding.•Usesmagneticfieldtokeepenergycenteredinthewaveguide.•Filledwithaninertgastopreventarcingduetohighvoltageswithinthewaveguide.2019/12/16SDE_01introduction23影响雷达性能的因素FactorsThatAffectRadarPerformance•SignalReception信号接收•ReceiverBandwidth接收机带宽•PulseShape脉冲波形•PowerRelation功率因素•BeamWidth波瓣宽度•PulseRepetitionFrequency脉冲重复频率•AntennaGain天线增益•RadarCrossSectionofTarget目标的雷达反射面RCS•Signal-to-noiseratio信噪比•ReceiverSensitivity接收机灵敏度•PulseCompression脉冲压缩•ScanRate扫描速度–Mechanical机械式–Electronic电子式•CarrierFrequency载波频率•Antennaaperture天线孔径2019/12/16SDE_01introduction24RadarReceiverPerformanceFactors•SignalReception•Signal-to-NoiseRatio•ReceiverBandwidth•ReceiverSensitivity2019/12/16SDE_01introduction25信号接收SignalReception•OnlyaminuteportionoftheRFisreflectedoffthetarget.仅有部分射频信号从目标反射出来•Onlyafractionofthatreturnstotheantenna.仅有一小部分返回到接收天线•Theweakerthesignalthatthereceivercanprocess,thegreatertheeffectiverange.接收机能够处理的信号越小，雷达的作用范围就越大。2019/12/16SDE_01introduction26Signal-to-NoiseRatio•MeasuredindB!!!!!•Abilitytorecognizetargetinrandomnoise–Noiseisalwayspresent.–Atsomerange,noiseisgreaterthattarget’sreturn•Noisesetslowerlimitofunit’ssensitivity•ThresholdlevelusedtoremoveexcessnoiseThreshold2019/12/16SDE_01introduction27ReceiverBandwidth接收机带宽•Frequencyrangereceivercanprocess接收机能够处理的频率范围•Receivermustprocessmanyfrequencies接收机必须处理的很多频点–Pulsesgeneratedbysummingsinewavesofvariousfrequencies脉冲波形由很多频率成分组成–FrequencyshiftsoccurfromDopplerEffects多普勒频移导致…•Reducingthebandwidth降低带宽–Increasessignal-to-noiseratio增强信噪比(good)–Distortstransmittedpulse发射波形变形(bad)2019/12/16SDE_01introduction28ReceiverSensitivity接收灵敏度•Sma