空中领航学(E01)ppt课件

.,空中领航学,AirNavigation,课件制作课程讲授,王惠民,北京航空航天大学,飞行学院,.,Flight,orairnavigationisthemeansbywhichpilotsreachtheirdestinationandfindtheirexactlocationatanytime.,.,空中领航学是引领飞机航行的一门应用学科，它以地球作为参照系来研究飞机相对于地球的运动及其导航方法。,空中领航学所要解决的三大基本问题，是确定：飞机位置飞机航向飞行时间,.,空中领航学研究的主要内容：领航基础及元素；领航原理和方法；领航设备工作原理和使用；领航误差及修正原理；领航准备和实施。,.,学科交叉,师生互动,.,本课件(共九章)系根据西澳教材AnAviationTheoryCentreManual-MeteorologyandNavigation，即ThePilotsManual系列丛书第二册制作，仅供课堂教学使用。特此申明，谨向该书编者致谢。,.,Chapter1FundamentalsofAirNavigation,BasicPrinciples,Thebasicprinciplesofairnavigationapplytoallaircraft,fromthesimplesttrainerstothemostsophisticatedpassengerjets.Whenflyingcross-country,youarethepilot,thenavigatorandtheradiooperator.,你既是驾驶员,也是领航员，又是无线电通信员。,BasicPrinciples,.,Asapilot,youmustaviate,navigateandcommunicate.,.,TypesofNavigation,ThebasicmethodofnavigationinVFR(day)operationsismapreading,whichisvisual-contactnavigation.Itrequiresmoreorlesscontinuousvisualreferencetothegroundandisthereforeoflimitedvalueinpoorvisibilityconditionsorwhennavigatingaboveextensivecloudcover.,TypesofNavigation,ThebasicmethodofnavigationinVFR(day)operationsismapreading,whichisvisual-contactnavigation.Itrequiresmoreorlesscontinuousvisualreferencetothegroundandisthereforeoflimitedvalueinpoorvisibilityconditionsorwhennavigatingaboveextensivecloudcover.,TypesofNavigation,.,Toassistuswithourvisualnavigationprocedures,wecanuseanyradionavigationequipmentinstalledinouraeroplanetoobtaininformationfromground-basedradiobeacons.,Tosupportvisualnavigationprocedures,weusedeadreckoning(DR)todeduceourposition.,Toassistuswithourvisualnavigationprocedures,wecanuseanyradionavigationequipmentinstalledinouraeroplanetoobtaininformationfromground-basedradiobeacons.,Tosupportvisualnavigationprocedures,weusedeadreckoning(DR)todeduceourposition.,.,FormoftheEarth,Allairnavigationisdonewithreferencetothesurfaceoftheearth.,ForpracticalpurposetheearthcanbetreatedasaperfectspherewithanaveragediameterofR=6371.004km.,ShapeandSize,地球半径：,R,.,RotationoftheEarth,Polaraxis,Truesouth,Truenorth,Theearthrotatestowardtheeast.,极轴,6633,.,ImaginaryLinesontheEarthsSurface,GreatCircles大圆,Agreatcircle(GC)drawnontheearthssurfacehasaplanewhichpassesthroughthecentreofthesphere(earth).大圆以地球的球心为其圆心。,经线,赤道,无,线,电,信,号,.,Greatcircle,Smallcircle,.,大圆具有如下特点：大圆是在球体表面上所能画出的最大的圆；在球体表面两点之间的最短距离是大圆的弧；除了像地球的地理两极（径向相反）的两点以外，在球体表面上两点之间只能画出一个大圆。,.,SmallCircles小圆,Asmallcircleisanycircleonthesurfaceofaspherethatisnotagreatcircle;thatis,thecentreofasmallcircleisnotatthecentreoftheearth.在地球表面上除大圆以外的圆，其圆心不是球心。,Theplaneofasmallcircledoesnotpassthroughthecentreofasphere.小圆平面不通过球心。,球心,圆心,.,Latitude纬度,南极,北极,赤道,.,Latitude,纬度,.,Longitude经度,南极,北极,本初子午线,(0经线),英国伦敦格林威治,皇家天文台,.,Longitude,经度,.,PositionontheEarth,Theusualmethodofspecifyingtheexactpositionofanypointonearthisbyreferencetoimaginarylinesofformingthelatitudeandlongitudegridonthesurfaceoftheearth.参照地球表面的纬度和经度网格,可为地球上任何一点精确定位。,例如:北京3957N,11628E,.,Themorecommonlymethodstopasspositioninformationbyradioincludethefollowing:Statingapositionasover(过)orabeam(切)alandmarkoranavigationaid;andStatingthedistance(距离)andbearing(方位)ofanaircraftfromalandmarkoranavigationaid.,Alternativemethodsforspecifyingaircraftposition.,.,Direction,Directionistheangularpositionofonepointtoanotherwithoutreferencetothedistancebetweenthem.Tomeasuredirection,thefullcircleisdividedinto360.,Itisusualtorefertodirectionasathree-figuregrouptopreventanymisunderstanding.,.,BeechcraftBE-55,PiperP28A,CessnaC150,Themostfundamentalreferencefromwhichanglesaremeasuredisthatoftruenorth,from000Tthrough090T,180T,270Tto360T.,.,NM,.,Agreatcirclecrossessuccessivemeridiansatagraduallychangingangle.Arhumblinecrossesallmeridianslongitudeatthesameangle.,Inpracticalterms,thegreat-circledirectionandtherhumb-linedirectionmaybeconsideredtobethesameovershortdistances,saylessthan200nm.,.,TrueDirection,Whenwemeasuredirectionbyreferencetothelocalmeridian,weareusingthenorthgeographicpoleortruenorthasthereference.Thisdirectionisreferredtoastruedirection.,Directionismeasuredfromameridian.,.,MagneticDirection,Theactualdirectionshownbyafreelysuspendedmagnetiscalledmagneticnorth,andthisisthedatumweusetomeasuremagneticdirection.,Theearthsmagneticfield.,.,Variation磁差,Variationistheangulardifferencebetweentruenorthandmagneticnorth.Variationeast,magneticleast;variationwest,magneticbest.,.,地球磁场,磁差,.,Isogonalsandtheagonicline.,AirportPERTHJANDAKOT32551S1155252EMagVar:1.483W,U.S.A.,Australia,.,.,RelativeBearings相对方位角,Therelativebearingofanobjectfromanaeroplaneisitsangulardistancefromtheaircraftsheadingmeasuredclockwisefromthenoseoftheaeroplanefrom000RELthroughto360REL.,RB=035,.,Conversions换算,ARelativeBearingAMagneticBearing,Aircraftmagneticheading,+,Relativebearingofobjectfromaircraft,=,Magneticbearingofobjectfromaircraft,飞机航向角+相对方位角=磁方位角,NM,Aircraftmagneticheading,Relativebearingofobjectfromaircraft,.,Distance,Fornavigationpurposes,theunitofmeasurementofhorizontaldistanceisthenauticalmile(nm).Forotheraviationuses,suchasvisibility,horizontaldistancefromcloudandrunwaylengths,theunitiseitherthekilometerormeter.,UnitsofMeasurement,.,TheNauticalMile海里,Thenauticalmilehasitsorigininitsrelationshiptothesizeoftheearth,where1minoflatitudeisequalto1nm.,1nm=1,852m,AnauticalmileisabsolutelynotanImperialmeasurement,althoughmanythinkitis.,10nm,10min,.,Speed,AirspeedandGroundspeed,Becauseoftheeffectofthewind,thespeedofanaeroplanecanbeexpressedintwoways:Itismeasuredinrelationtotheground,groundspeed.Itismeasuredrelativetotheairmassthroughwhichitismoving,airspeed.,.,Theeffectofthewindonthespeedofanaeroplane.,.,BAS（基本表速）-shownbyASIIAS（指示空速）CAS（校正空速）EAS（当量空速）TAS（真空速）-actualspeedthroughtheair,空速表机械误差修正,空气动力误差修正,空气压缩性修正,空气密度修正,AirspeedIndicator,.,TrueAirspeed(TAS),Fornavigationpurposesweneedtoknowourtrueairspeed(TAS)oractualspeedthroughtheair.,TAS=,CAS,/0,Where,/0istheairdensityratio.,/0,.,ForthesameIAS,warmerairincreasesTAS.,ForthesameTAS,theaircraftinlessdenseairhaslowerIAS.,TAS80kt,IAS80kt,TAS93kt,IAS80kt,.,MovementinanAirMass,Velocity,Thevelocityisarateofchangeofpositioninagivendirectionandisthereforeacombinationofbothspeedanddirection.,MovementinanAirMass,Velocity,.,WindVelocity风速向量,Thewindvelocityisnearlyalwaysexpressedasafive-orsix-figuregroup;thefirstthreefiguresarethedirectionfromwhichthewindblows,andthelasttwoorthreeindicatethespeedofthewind.,.,GroundVelocity地速向量,TheresultduetothewindvelocityeffectisthattheaeroplanehasanothervelocityinadditiontothatdescribedbyitsheadingandTAS,andthisisthegroundvelocity,oritstrackandgroundspeed.,TR/GSvectors.,.,VectorAddition向量加法,.,TheTriangleofVelocities航行速度三角形,HDG/TAS+W/V=TR/GS,航向/真速+风向量=航迹/地速,W/V,TR/GS,HDG/TAS,TheTriangleofVelocities航行速度三角形,HDG/TAS+W/V=TR/GS,.,Thewindsideofatypicalnavigationcomputer.,.,Altimetry(VerticalNavigation),VerticalMeasurement,Altitude(高度)istheverticaldistanceofalevel,apoint,oranobjectconsideredasapoint,measuredfrommeansealevel(MSL).,FlightLevel(高度层)isasurfaceofconstantatmosphericpressurethatisrelatedtoaspecifiedpressuredatum,1,013.2hPa,andisseparatedfromothersuchsurfacesbyspecifiedpressureintervals.,Height(高)istheverticaldistanceofalevel,apoint,oranobjectconsideredasapoint,measuredfromaspecifieddatum.,.,ApressurealtimetercalibratedinaccordancewiththeInternationalStandardAtmospherehasthefollowingproperties:,WhensettoaQNHaltimetersetting,itwillindicatealtitude;,Whensettoapressureof1,013.2hPa,itmaybeusedtoindicateflightlevel.,Note.QFEsettingsarenotusedinAustralia.,AltimeterSettings,WhensettoaQFEaltimetersetting,itwillindicateheightabovetheQFEreferencedatum;,.,TheactualMSLpressureatanyoneplaceiscalledQNH,andanaltimetersettoQNH(withthealtimetersubscalesettotheactualMSL)willindicatealtitude.,QNHSetting,QNHSetting,.,VariationsinMeanSeaLevelPressure,TheactualMSLpressurediffersmostofthetimefromthatunderISAconditions,anditalsovariesfromdaytoday,andevenfromhourtohour,asthevariouspressuresystemsmoveacrossthecountry.,.,Thechartsweusefornavigationshowtheheightabovemeansealevelofallhighgroundandobstacles.Therefore,withthealtimetersettoQNH,wewillhaveanimmediateindicationofourverticalseparationfromthegroundbeneathus(terrainclearance).,.,EffectofVariationintheMSLPressure,Planandprofileviewsofsynopticsituation.,.,TheconstantvariationofMSLpressurehasthepotentialtocausetwosignificantoperationalproblems.,IfcorrectionsarenotmadetotheQNHsettingthefollowingwilloccur:TerrainClearance（离地高度）whenflyingfromhighpressuretolowpressure,thealtimeterwillover-read.whenflyingfromlowpressuretohighpressure,thealtimeterwillunder-read.,Fromhightolow,bewarebelow.,从高(压区)飞往低(压区)，当心高度低。,.,TrafficSeparation（空中交通间隔）,SafetrafficseparationrequiresallaircraftinthesamevicinitytousethesameQNHaltimetersetting.,.,AreaQNH,Toensureaproperverticalseparation,allaircraftoperatinginthesamegeneralvicinitymustusethesamealtimetersubscalesetting,theareaQNH.AreaQNHsettingsareusedbyallaircraftoperatingatorbelow10,000ftAMSL(transitionaltitude).TheareaQNHisaforecastvaluethatisvalidforaperiodof3hrandnormallyappliesthroughoutanareaQNHzone.Beforeflight,theareaQNHwillbeavailablethroughtheAVFAXsystem.Inflight,theareaQNHwillbeavailablefromATS.,.,AccuracyofAreaQNHSetting,AreaQNHvaluesarerequiredtobeaccuratetowithin5hPaoftheactualQNHatanylow-levelpoint(below10,000ftAMSL)within,oron,theboundaryoftheirrespectiveAQZsduringtheperiodofvalidityoftheforecast.Theindicatedaltitudewillbewithin150ftoftheactualaltitudeanywhereintheassociatedAQZ.,AccuracyofAreaQNHSetting,AreaQNHvaluesarerequiredtobeaccuratetowithin5hPaoftheactualQNHatanylow-levelpoint(below10,000ftAMSL)within,oron,theboundaryoftheirrespectiveAQZsduringtheperiodofvalidityoftheforecast.Theindicatedaltitudewillbewithin150ftoftheactualaltitudeanywhereintheassociatedAQZ.,.,FlightLevels,Above10,000ft(thetransitionaltitude)weselectthestandardMSLpressureof1,013hPa,andwiththealtimetersettothis,weflyatflightlevels.,CruisingFlightLevels,CruisingAltitudes,.,PressureHeight(PressureAltitude),Therearetwomethodsofdeterminingpressurealtitude:wecanset1,013hPaonthealtimetersubscaleandreadoffdirectlythevalueofthepressureheight;orwecanmakeasimplecalculationasshownbelow,usingourknowledgethatupto5,000ft,theapproximaterateoffallofpressureis1hPaper30ft.,.,Howtofindpressureheight.,Example:,When1,013isgreaterthanQNH,pressureheightisgreaterthanelevation.,.,Howtofindpressureheight.,Example:,When1,013islessthanQNH,pressureheightislessthanelevation.,.,AltimeterSettingRules（