《智能传感器装调与测试（双语）》课件-16.多普勒效应测速原理

多普勒效应测速原理DopplerEffectVelocimetryPrinciple测速是智能网联汽车环境感知系统中和一项核心需求，离不开多普勒效应。SpeedmeasurementisacorerequirementintheenvironmentalperceptionsystemofintelligentconnectedvehiclesandcannotbeseparatedfromtheDopplereffect.PART01基本原理BasicPrinciples多普勒效应基本原理ThreeKeyStepsintheWorkingPrincipleofBinoculartheDopplerEffect定义Definition当波源与观测者发生相对运动时，观测者接收到的频率会与波源发射频率不同，这种现象称为多普勒效应。Whenthewavesourceandtheobservermoverelativetoeachother,thefrequencyreceivedbytheobserverwillbedifferentfromthefrequencyemittedbythewavesource.ThisphenomenoniscalledtheDopplereffect.汽车应用Automotiveapplications主要应用于电磁波雷达，如毫米波雷达和激光雷达，其电磁波传播速度接近光速，用于测量车辆的相对速度。Itismainlyusedinelectromagneticwaveradar,suchasmillimeter-waveradarandLiDAR.Itselectromagneticwavepropagationspeedisclosetothespeedoflightandisusedtomeasuretherelativespeedofvehicles.PART02频率偏移换算FrequencyOffsetConversion参数定义与符号约定ParameterDefinitionandSymbolConvention发射频率(f_0)

Transmissionfrequency(f_0)发射频率(f_0)是雷达发射的电磁波频率，例如车载毫米波雷达常用的77GHz。Thetransmissionfrequency(f_0)isthefrequencyofelectromagneticwavesemittedbyradar,suchas77GHzcommonlyusedinvehicle-mountedmillimeter-waveradar.相对速度(v)

Relativevelocity(v)相对速度(v)表示波源与观测者之间的相对运动速度，靠近时取正值，远离时取负值，单位为m/s。Relativevelocity(v)representstherelativespeedofmotionbetweenthewavesourceandtheobserver,takingapositivevaluewhenapproachingandanegativevaluewhenmovingaway,inm/s.电磁波传播速度(c)

Electromagneticwavepropagationspeed(c)电磁波传播速度(c)约为光速，即(3×10^8m/s)。Thepropagationspeedofelectromagneticwaves(c)isaboutthespeedoflight,thatis,(3×10^8m/s).总频率偏移（Δf）

Totalfrequencyoffset(Δf)雷达测速中，由于电磁波发射、反射和接收经历两次多普勒效应，总频率偏移Δf=∣f1−f0∣。Inradarspeedmeasurement,duetothetwoDopplereffectsofelectromagneticwavetransmission,reflectionandreception,thetotalfrequencyshiftΔf=∣f1−f0∣.接收频率公式推导Derivationofreceivingfrequencyformula推导过程Derivationprocess接收到的波长λ1=f0/c−vReceivedwavelengthλ1=f0/c−v波源发射的波长为λ0=f0/cThewavelengthemittedbythewavesourceisλ0=f0/c观测者接收到的频率f1=c/λ1thefrequencyreceivedbytheobserverisf1=c/λ1接收到的频率f1=f0×c/c−vthereceivedfrequencyf1=f0×c/c−vf1≈f0×(1+v/C)f1≈f0×(1+v/C)PART03测速注意事项PrecautionsforSpeedMeasurement方向判断与非径向修正Directionjudgmentandnon-radialcorrection▶1.方向判断

DirectionjudgmentWhenΔfisalwayspositive,itmeansthatthereceivedfrequencyishigherthanthetransmittedfrequency,andthetwoareclosetoeachother,sovispositive;whenΔfisalwaysnegative,thereceivedfrequencyislowerthanthetransmittedfrequency,andthetwoarefarawayfromeachother,sovisnegative.当Δf总为正值时，说明接收到的频率高于发射频率，两者相互靠近，v为正；当Δf总为负值时，接收到的频率低于发射频率，两者相互远离，v为负。方向判断与非径向修正Directionjudgmentandnon-radialcorrection▶2.非径向运动修正

Non-radialmotioncorrectionTheDopplereffectisonlysensitivetotheradialvelocitycomponent.Ifthetargethasnon-radialmotion,acorrectionformulaneedstobeintroduced.多普勒效应仅敏感径向速度分量，若目标存在非径向运动，需引入修正公式。Forexample,whenθ=60andcos60°=0.5,ifthetotalrelativevelocityisdirectlyusedforcalculation,theresultwillbe2timesoftheactualradialvelocity.比如θ=60时，cos60°=0.5，若直接用总相对速度计算，得到的结果会是实际径向速度的2倍本讲小结SummaryofThisLecture总结Summary掌握：多普勒效应测速的核心原理，尤其是频率偏移与相对速度的换算关系。Master:thecoreprincipleofDopplereffectvelocimetry,especiallytheconversionrelationshipbetweenfrequencyoffsetandrelativevelocity.课后练习：用已知参数（如给定雷达发射频率和