空中领航学(E_01).ppt

空中领航学 AirNavigation 课件制作课程讲授 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ThePilot sManual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 66 33 ImaginaryLinesontheEarth sSurface GreatCircles大圆 Agreatcircle GC drawnontheearth ssurfacehasaplanewhichpassesthroughthecentreofthesphere 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 北京39 57 N 116 28 E Themorecommonlymethodstopasspositioninformationbyradioincludethefollowing Statingapositionasover 过 orabeam 切 alandmarkoranavigationaid and Statingthedistance 距离 andbearing 方位 ofanaircraftfromalandmarkoranavigationaid Alternativemethodsforspecifyingaircraftposition Direction Directionistheangularpositionofonepointtoanotherwithoutreferencetothedistancebetweenthem Tomeasuredirection thefullcircleisdividedinto360 Itisusualtorefertodirectionasathree figuregrouptopreventanymisunderstanding BeechcraftBE 55 PiperP28A CessnaC150 Themostfundamentalreferencefromwhichanglesaremeasuredisthatoftruenorth from000 Tthrough090 T 180 T 270 Tto360 T NM Agreatcirclecrossessuccessivemeridiansatagraduallychangingangle Arhumblinecrossesallmeridianslongitudeatthesameangle Inpracticalterms thegreat circledirectionandtherhumb linedirectionmaybeconsideredtobethesameovershortdistances saylessthan200nm TrueDirection Whenwemeasuredirectionbyreferencetothelocalmeridian weareusingthenorthgeographicpoleortruenorthasthereference Thisdirectionisreferredtoastruedirection Directionismeasuredfromameridian MagneticDirection Theactualdirectionshownbyafreelysuspendedmagnetiscalledmagneticnorth andthisisthedatumweusetomeasuremagneticdirection Theearth smagneticfield Variation磁差 Variationistheangulardifferencebetweentruenorthandmagneticnorth Variationeast magneticleast variationwest magneticbest 地球磁场 磁差 Isogonalsandtheagonicline AirportPERTHJANDAKOT32 5 51S115 52 52EMagVar 1 483 W U S A Australia RelativeBearings相对方位角 Therelativebearingofanobjectfromanaeroplaneisitsangulardistancefromtheaircraft sheadingmeasuredclockwisefromthenoseoftheaeroplanefrom000RELthroughto360REL 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 Planandproofsynopticsituation 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 Theindicatedaltitudewillbewithin 150ftoftheactualaltitudeanywhereintheassociatedAQZ AccuracyofAreaQNHSetting AreaQNHvaluesarerequiredtobeaccuratetowithin5hPaoftheactualQNHatanylow levelpoint below10 000ftAMSL within oron theboundaryoftheirrespectiveAQZsduringtheperiodofvalidityoftheforecast Theindicatedaltitudewillbewithin 150ftoftheactualaltitudeanywhereintheassociatedAQZ FlightLevels Above10 000ft thetransitionaltitude weselectthestandardMSLpressureof1 013hPa andwiththealtimetersettothis weflyatflightlevels CruisingFlightLevels CruisingAltitudes PressureHeight PressureAltitude Therearetwomethodsofdeterminingpressurealtitude wecanset1 013hPaonthealtimetersubscaleandreadoffdirectlythevalueofthepressureheight or wecanmakeasimplecalculationasshownbelow usingourknowledgethatupto5 000ft theapproximaterateoffallofpressureis1hPaper30ft Howtofindpressureheight Example When1 013isgreaterthanQNH pressureheightisgreaterthanelevation Howtofindpressureheight Example When1 013islessthanQNH pressureheightislessthanelevation AltimeterSettingRules 高度表拨正规则 Youarenotpermittedtocruis