空中领航学(E_06)ppt课件

.,北京航空航天大学飞行学院,空中领航学,AirNavigation,课件制作课程讲授,王惠民,.,NM,340M,AcorrectlytunedADFindicatesthedirectionofaselectedNDBfromtheaircraft.,.,NDB-ADFCombination,TheNDB(non-directionalbeacon)isagroundradiotransmitter;andtheADF(automaticdirectionfinder)isareceiverintheaircraft.,ThepilotisabletodeterminewithreferencetotheaircraftmagneticheadingapositionlinebetweentheaircraftandNDB.,.,TheNDB-ADFsystemisusedforthefollowingpurposes:orientation(whereamI?);enroutenavigation(trackingfrompointtopoint);holdingoverspecifiedpoints;andinstrumentapproaches.,.,Non-directionalbeaconsaresimpleground-basedtransmittersthatradiateanomni-directional(alldirections)signal.NearlyallNDBsinAustraliaoperateonfrequenciesbetween200kHzand400kHz.MostNDBsareprimarilyshort-distancenavigationaids,usefulfordistanceslessthan200nm.,Non-DirectionalBeacon(NDB),Non-DirectionalBeacon(NDB),.,TwotypesofNDBtransmissionantennas.,ThetransmitterpowerofmostNDBsisbetween100Wand3,000W.,.,MostNDBsareinstalledinpairs,withamainandstandbyincaseoffailure,andareextremelyreliableaids.CivilAviationSafetyAuthoritypersonnelatnearbyaerodromesmonitortheNDBswithinrange,butNDBsinremoteareasshouldbemonitoredbypilotsandanyfaultsreportedbyradiotoallowearlyrectification.,NDBReliability,.,NDBfrequencies,identcodesandgeographicalpositionsarefoundinthefollowingpublications:EnRouteSupplementAustralia(ERSA);enroutecharts(ERC);visualnavigationcharts(VNC);andvisualterminalcharts(VTC).,WheretoFindDetailsofanNDB,.,DetailedinformationforeachNDBispresentedintheERSA.,Ratedcoverage,Position,Ident,Ident,Ident,Frequency212KHz,.,NDBdetailsonanERC-L.,NDBdetailsonaVTC.,.,BroadcastingStations,Broadcastingstationsoperatingintherangeof5001,600kHzmayalsobereceivedonanADF.theycanbedifficulttoidentify;youcanbeeasilydistractedbythem;theymaybeunreliable;andnoinformationonrangeispublished.,.,ComponentsandPrincipleofOperation,AutomaticDirectionFinder(ADF),ThebasicpurposeoftheADFistoindicatetothepilotthedirectionoftheNDBtowhichtheADFistuned.,AutomaticDirectionFinder(ADF),TheADFneedlepointsdirectlytowardstheselectedNDBgroundstation.,.,ADFcomponents.,.,ADFreceiver,ADFsingleneedle,ADFdualneedles,.,Receiver,ThereceiverandassociatedcontrolpanelisusedtotunetheADFtothefrequencyoftheNDBthatyouhaveselectedtouse.,Antenna,ThemodernADFantennasystemactuallyconsistsoftwoaerials:aloopaerialandasenseaerial.,.,CockpitDisplay,TheADFcockpitdisplayconsistsofacompass,orazimuth,cardplacedverticallyontheinstrumentpanel,withapointerorneedlethatrotatesthroughthefull360.,.,ADFOperation,Asageneralrule,thefollowingprocedureapplies:Switchon;SelectADFandtunethefrequencyoftheNDB;IdentifythesignalfromtheNDB.ThebestapproachistohaveinyourmindtheMorsecodesymbolsyouexpecttohear,anthenlistencarefullytotheidenttoverifythatyouhavethecorrectNDB;CheckthatitisADFing.,Note:Nevertrustasignalthathasnotbeenaccuratelyidentified.,.,DifferentTypesofADFIndicator,Toconveyinformationtothepilot,ADFindicatorsusethreedifferentpresentations:thefixed-cardADF,orrelativebearingindicator(RBI);themanuallyrotatablecard,andtheradiomagneticindicator(RMI).,.,Fixed-CardADF,Onthefixed-carddisplay,theADFneedleindicatestherelativebearingoftheNDBgroundstationfromtheaeroplane.,Afixed-cardADFisarelativebearingindicator(RBI).,.,ItissometimesconvenienttodescribethebearingoftheNDBrelativetothenoseortailoftheaeroplane.,TheRBIshowsrelativebearings,.,Eachtimetheaeroplanechangesitsmagneticheading,itwillcarrythefixedcardwithit,buttheneedlecontinuestopointatthestation.Therefore:Witheachchangeofmagneticheading,theADFneedlewillindicateadifferentrelativebearing.,.,PeriodicallyrealigntheDGwiththemagneticcompass.,Wenormallyflymagneticheadingsusingthedirectionalgyro(DG)asthereferenceinstrument.TheDGmustberealignedwiththemagneticcompassthroughouttheflightatregularintervals.,.,OrientationusingtheRBI.,.,Aeroplanemagneticheading,MagneticbearingtoNDBfromaeroplane,RelativebearingofNDBfromaeroplane,MagneticbearingofaeroplanefromNDB,+,=,+/180,=,+,MB130FROM,-,MH280,RB030,=,MB310TO,180,=,.,MagneticBearingandHowtoVisualiseit,Aquickmethodofdeterminingamagneticbearing(MBTO)usinganRBIandaDGistopicturetheADFneedlespositiononthefaceoftheDG.,.,ManualRotatable-CardADF,WhentheADFcardismanuallyalignedwiththeDG,theADFneedlewillindicatethemagneticbearingto(MBTO)theNDB.Thetailoftheneedleindicatesthemagneticbearingoftheaircraftfrom(MBFROM)theNDB.Therotatable-cardcanstillbeusedasafixed-cardsimplyby,leaving000setundertheindex.,Anytimeyoualterheading,youmustrealigntheADFcardwiththeDG.,ArotatablecardADF,.,RadioMagneticIndicator(RMI),TheRMIdisplayhastheADFneedlesuperimposedonacardthatiscontinuouslyandautomaticallybeingalignedwithmagneticnorth.Itisanautomaticversionoftherotatable-cardADFanautomaticcombinationoftheDGandRBI.,.,TheRMIneedlewillalwaysindicatethemagneticbearingtotheNDB,andthetailoftheRMIneedlewillindicatethemagneticbearingfromtheNDB.,.,ADFIndicatorswithTwoNeedles,AnRMIwithtwoneedles.,MostRMIshavefunctionswitchesthatallowapilottoselecttheRMIneedletopointateitheranNDBoraVOR.,.,UsingtheADFtoObtainPositionLinesfromanNDB,TheADFcanbeusedtoassistyouinyourvisualnavigation,aswellasbeingthesolemeansofnavigation.WecanusetheADFtodothefollowing:obtainapositionline;tracktoanNDB;determineyourpositiondirectlyoveranNDB;trackawayfromanNDB;interceptaplannedtrack;andassessyourpositionabeamanNDB.,.,UsingtheADFtoObtainPositionLinesFromanNDB,Therearetwoperspectivesfromwhichwecandeterminetherelativepositionsofandaircraftandaradiobeacon:Fromtheaircraft,asapilotinflightwould,whichisthebearingoftheNDBfromtheaircraft;andFromthegroundstation,whichisthebearingoftheaircraftfromtheNDBandmaybenecessaryifyouwanttoplotthepositionoftheaircraftonachart.,.,UsingtheRBI(Fixed-cardADF),AfewexamplesthatshowhowtheRBI(i.e.fixed-cardADF)maybeusedtoestablishbearingsandpositionlines:,.,Followthroughthestepsinsequence:,.,AnEasierMethodofDeterminingMagneticBearing,Relativebearingarenormallyspecifiedusingthemethod(clockwisefromthenose).Theycanalsobethoughtofaseitherleftorrightofthenose(orthetail).,QuadrantsforconvertingRBstoMBs,.,Usingthismethod,youmustrememberthatoffthenosegivesmagneticbearingsTOtheNDB,offthetailgivesbearingsFROMtheNDB.,.,UsingtheRotatable-CardADFortheRMI,ApartfromensuringcorrectsynchronisationwiththemagneticcompassandcorrecttuningandidentificationoftheNDB,allyouhavetodoisreadoffthemagneticbearingdirectly.,ThemagneticbearingtoanNDBstationisreadfromtheheadoftheneedle,andthemagneticbearingfromtheNDBisreadfromthetail.,OrientationwithanRMIisstraightforward.,.,PlottingtheADF-NDBPositionLine,ThebearingsobtainedfromanADForanRMIaremagneticbearings.Beforetheycanbeplottedonachart,theymustbeconvertedintotruebearingsbycorrectingforthemagneticvariationthatappliesinthevicinityoftheaircraft.,Strictlyspeaking,itisthemagneticvariationattheaircraftpositionwhichisapplied,andnotthevariationattheNDBstationitself.,.,WhenplottingADFbearingsonachart,thefollowingstepsshouldbefollowed:,DeterminethemagneticbearingfromtheNDB.Determinethemagneticvariationinthevicinityoftheaircraft.ConvertthemagneticbearingtothecorrespondingtruebearingfromtheNDB.Byaligningaplotterorprotractorparallelwiththenorth-southmeridianatthestationconcerned,plottheresultingpositionlineradiatingfromtheNDB.,.,PlottingapositionlinefromanNDB.,YouaresteeringMH280andobtainanADFreadingofRB050.Thevariationinyourareais6W.Determinethetruebearing(TB)toplotfromtheNDBstation.,MH280+RB050=MB330TO,-180,=MB150FROM,-6WVAR,PlotTB144FROM,.,TrackingProceduresUsingtheADF,WhenflyingtowardsanNDB,theADFneedlewillpointaheadoftheaircraft(approximatelyRB000),andwhenflyingawayfromanNDB,theADFneedlewillpointbehindtheaircraft(approximatelyRB180).AsanaircraftapproachesanNDBgroundstation,theADFneedlewillbecomemoreandmoresensitive.Onpassingoverhead,theneedlewillswingfrompointingaheadtopointingbehind(infact,itmayoscillatewidelyduringstationpassage,completingseveralcircuitsoftheindicatorcardinrandomdirections).,TrackingProceduresUsingtheADF,.,TrackingTowardsanNDBUsingtheRBI,WithNoCrosswindEffect,Ifthereisnocrosswindtoblowtheaircraftofftrack,wecansettheheadingastrack,andtheaircraftshouldflydirectlytothedestination.,Trackinginboundwithnocrosswindeffect.,.,InaCrosswind,WithNoCorrectionforDrift,Crosswindhascausedtrackerror.,.,Thedifferencebetweenhomingandtracking.,Homingisaprocedurethatshouldnotbeused.Thecorrectprocedureistoregaintheintendedtrack,andalterheadingtotheleft(right)toallowforright(left)drift,thecorrectamountofdriftbeingfoundbytrialanderrororbycalculation.,.,ItismorethanlikelythatthewindeffectwillchangeasyoutracktowardsanNDB,andregularadjustmentstoheadingwillthereforeberequired.Withpractice,youwillfinditquiteeasytoassessthedriftandtheconsequentwindcorrectionangle(WCA)tobeappliedsoastoremainmoreorlessonyourintendedtrackintotheNDB.,.,WithCorrectDriftCorrectionApplied,Witha5leftWAC,youwouldexpecttoseetherelativebearingoftheNDBfromtheaircraft(RB005)remainunchangedasyoutrackedinontrack096steeringMH091.,.,WithIncorrectDriftCorrectionApplied,Ifanincorrectdriftcorrectionismade,thenyouwilldriftofftheplannedtrack;thatis,theRBindicationandtheMBTOtheNDBwillchange.Ifasteadyheadingisbeingflown,thenandivergencefromtrackwillbecomeobviousthroughagraduallychangingrelativebearing,withtheADFneedlemovingleftorrightdownthedial.,.,Driftistheanglebetweenheadingandthetrack.TheperfectWCAwillcounteractanydriftexactly,andthetrackmadegoodwillfollowtheintendedorplannedtrack.,.,HowtoRegainandThenMaintainTrack,IftherewasonlyashortdistancetoruntotheNDBstation,youcouldtrackdirectlytoitfromthepresentposition.,FlyinganewtracktotheNDB.,.,HowtoRegainandThenMaintainTrack,Regainandmaintaintheplannedtrack.,Iftherewasalongdistancetorun(say20nm),youmightdecidetotakeuptrackasheading,lettingthewinddriftyoubackontotrack,andoncebackonit,steeracorrectMH,whichwouldallowforarightdrift.,.,Headofneedlefallingright,turnright;Headofneedlefallingleft,turnleft.,.,If,whensteeringasteadymagneticheading,theADFneedleindicatesaconstantrelativebearingnearthetopofthedial,thenyouaretrackingdirectlytotheNDBandnocorrectiontoheadingisnecessary.,IfMH+RB=constantMB,trackingisgood.,.,Justhowbigacorrectionyouneedtomakedependsuponhowfaryouhavestrayedoffyourintendedtrack.Asimplemethodistodoubletheerror.,Regainingtrackbydoublingtheerror,andmaintainingtrackthereafter.,.,WhatToDoifUncertainofWindEffect,Ifthewinddirectionandstrengthisnotobvious,thenthebesttechniqueistoinitiallysteertrackasheading,makingnoallowancefordrift.TheeffectofthewindwillbecomeobviousastheADFneedlemovestotheleftorright.Observetheresults,andthenmakeappropriateheadingadjustmentstomaintaintrack.,Ifuncertainofwind,initiallysteertrackasheading.,.,TrackingOveranNDBUsingtheRBI,TheADFneedlewillbecomemoreandmoresensitiveastheNDBstationisapproached.Foraverypreciseoverheadtobeachieved,youmustbepreparedtoincreaseyourscanrateastheNDBisapproachedandtomakesmallercorrectionsmorefrequently.,.,ClosetothestationandjustpriortopassingovertheNDB,youshould,atthispoint,relaxalittleandsteerasteadyheadinguntiltheaeroplanepassesovertheNDBindicatedbytheADFneedlemovingtowardthebottomofthedial.HavingpassedovertheNDB,trackingfromtheNDBshouldbecheckedandsuitableadjustmentsmadetoheading.,.,GoodADFtracking,ReasonableADFtracking,PoorADFtracking,.,WhentheADFneedlebecomesextremelyactiveandthenfallsrapidlytothebottomofthedial,itindicatesthatyouhavepasseddirectlyovertheNDB.IftheADFneedlemovesgraduallytoonesideandslowlyfallstothebottomofthedial,thenthisindicatesthatyouarepassingtoonesideofthebeacon.TherateatwhichtheneedlefallsindicatesyourproximitytotheNDB.Timewhenover(orabeam)theNDBwithnoWCAcanbetakenastheneedlefallsthroughtheapproximate090or270position.,.,TrackingAwayfromanNDBUsingtheRBI,WhentrackingawayfromanNDB,theheadoftheADFneedlewilllietowardthebottomofthedial.,WithNoCrosswindEffect,IfyoutrackovertheNDBandthensteertrackasheading,youwilltrackdirectlyawayfromtheNDBwiththeheadoftheADFneedlesteadyon180,andthetailoftheADFneedlesteadyatthetopofthedialon000.,.,TrackingawayfromanNDBwithnocrosswindeffect.,.,InaCrosswind,WithCorrectDriftCorrectionApplied,TrackingawayfromanNDBwithaWCAof5intowind.,MBFROMNDB=MH+/-deflectionofthetailoftheneedle.,.,WithIncorrectDriftCorrectionApplied,WhereasinaccuratetrackingtoanNDBisindicatedbytheADFneedlefalling,incorrecttrackingawayfromanNDBcanoccurwiththeADFneedleindicatingasteadyreading.,TrackingawayfromanNDBwithincorrectdriftcorrectionapplied.,.,TrackingAbeamanNDB,NilDrift,Inthiscase,headingisequaltotrack.Attheabeamposition,theADFwillindicateeitherRB090orRB270.,.,WithDrift,Ifacrosswindcomponentisactingontheaircraft,thentheheadingwilldifferfromthetrackbytheamountofdriftbeingexperienced.,RBIindicationsattheabeampositionwithdriftcorrectionapplied.,.,InterceptingaTrackUsingtheRBI,WhereamI?WheredoIwanttogo?HowdoIgetthere?,.,OrientatetheaeroplanerelativetotheNDB,andtotheplannedtrack.Turntotakeupasuitableinterceptheading,afterconsideringwhereyouwanttojointheplannedtrack.Maintaintheinterceptheading.Asyoucomeuptotheinterceptpoint,turntotheplannedtrack,andapplyasuitableWCAtomaintainit.,.,VisualisingWhereYouAreandWhereYouWanttoGo,TheDGcanassistgreatlyinvisualisingthesituation.WhatifyouwishtointercepttheintendedtrackinboundtotheNDB?Allyouneedtodoisvisualisetheintendedtrackontheheadingindicator.Withamodelaeroplaneonthetailoftheneedletrackingasintended,itbecomequiteclearwhatturnsarenecessarytointerceptthetrack.,.,.,Ifyoubecomedisoriented,asimpleprocedureistotakeuptheheadingoftheintendedtrack.Eventhoughnotontrack,theaeroplanewillatleastbeparalleltoit,andtheADFneedlewillindicatewhichwaytoturntointerceptit.,.,Visualisingtheintercept.,Aninefficientinterceptoftrack.,Differentinterceptoftrack.,.,InterceptinganInboundTrack,NM,Example:Interceptingtrack340inboundfromsouthofthestation.*,.,*Note:Anaeroplanetakessomedistancetoturn,andsoyoushouldanticipatetheintendedtrackbycommencingtheturnontotrackjustbeforeMB340isreached.YoucandothisbyobservingtherateatwhichtheADFneedlefallstoward-060andcommencetheturnaccordingly.,.,Anothermeansofachievingasmoothinterceptistoreducetheclosingangleastheinboundtrackisapproached,sayfrom45to30to15and,finally,tozeroasthetrackisintercepted.,Example:Interceptingtrack055inboundfromradarvector010.,.,Stepstobetakentointerceptaninboundtrack:,Orientatetheaeroplane.Alteryourheadingtointercepttheintendedtrack.TheADFneedlewillcontinuetopointattheNDBandsotherelativebearingwillchange.MaintainthemagneticheadingandperiodicallyobservetheRBIastheheadoftheneedlefalls.AstheneedlefallstotheexpectedRB(erceptingtheintendedtrack),turntotakeuptheintendedtracktotheNDB,allowingfortheestimatedcrosswindeffectontracking.,.,Example:Radarvector340tointercepttrack280outbound.,InterceptinganOutboundTrack,.,Stepstobetakentointerceptanoutboundtrack:,Orientatetheaeroplane.Considertheintercept.MonitortheinterceptbysteeringasteadyheadingandperiodicallycheckingtheRBItoseethetailoftheneedlerising.Astherequiredoutboundtrackisapproached,indicatedbythetailoftheneedle,turntopickitup,allowingfortheestimatedcrosswindeffectontracking.PeriodicallycheckthatMH+/-ADFtail=MBFROMNDB.,.,LimitationsandAccuracyoftheNDB-ADFCombination,Limitations,AsaresultofvariouslimitationsaffectingthesignalstransmittedbyanNDB,thebearingstakenbyanADFareliabletobeinerror.,.,NightEffect,Theindirectskywavemixeswiththedirectgroundwave(i.e.themainpathtakenbyradiowavesfromtheNDBgroundtransmitter,whichisalongthesurfaceoftheearth.)togiveacombinedsignalth