航空电子基础6-VOR.ppt

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1、AVIONICSFUNDAMENTALSVERYHIGHFREQUENCYOMNIRANGEVORVeryHighFrequencyOmniRangePurposeofaVORSystemVORisanenroute,station-to-stationRadioNavigationSystemProvidesHeadingandBearinginformationUsedtocreate“Airways”Assistsinproviding“PositionFix”Auto-tunesDMEwhenaVORfrequencyisselectedC

2、omponentsofaVORSystemAntennaReceiverControlHeadIndicationInterconnectingwiringandantennacoaxialcableLargeAircraftVORSystemsTheNAVreceiveristypicallylocatedintheradiorackoravionicscompartmentFrequencySelectorLargeraircrafthavearemotemountedfrequencyselectorinthecockpit.Oftenaco

3、mbinedNAV/COMfrequencyselectorUsuallymountedontheglareshieldorpedestalLightAircraftNAVControlHeadSmalleraircraftemployapanelmountedreceiverFrequencyselectionisonthefrontofthereceiverVORAntennasVORIndicationsVORindicationscanbedisplayedonavarietyofdifferentinstruments.“Manual”V

4、ORindicationsaredisplayedon“CourseDeviationIndicator”typeinstrumentsManualVORCDIIndicatorsHorizontalSituationIndicator(H.S.I.)Each“dot”ofdeviationrepresents5degrees.VORIndications“Automatic”VORindicationsaredisplayedonCompassInstrumentsRadioMagneticIndicator(RMI)TO/FROMINDIC

5、ATIONTheTO/Fromindicationwilltellyouwhattheaircraftwoulddo,IFyouweretoturnontotheselectedcourseheading.VORTheoryofOperationTheVORsystemoperatesintheVHFfrequencyband,from108.0to117.95MHz.NONLOCALIZERFREQUENCIESVORGroundStationVORuses2typesofmodulationA30HZFMReferenceSignalA30HZ

6、AMVariableSignalTheVORreceivercomparesthePHASEdifferencebetweenthetwosignalsFMReferenceSignalA30HZ,FM“Subcarrier”istransmittedomnidirectionalat(9960HZ,+/-480HZ)The“Subcarrier”isappliedasAmplitudeModulation(AM)totheR.F.30HZVariableSignalTheR.F.carrierwave(108-118MHZ)iselectroni

7、callyrotatedduringtransmission,ataspeedof1800RPM…Or30CyclesPerSecond(HZ)SynchronizingtheFMandAMTheFMReferencesignalissynchronizedwiththerotatingdirectional(AM)signalTheFMReferencewillalwaysbeatitspositivepeakwhenthedirectional(AM)signalispointedNORTHSynchronizingtheFMandAMVORr

8、eceiverswilldetecttheAMsignal’spositivepeak,whenthedirectiona