EnglishforUnmannedaerialvehicle無(wú)人機(jī)專業(yè)英語(yǔ)第一部分第二部分導(dǎo)航的發(fā)展與原理衛(wèi)星導(dǎo)航的分類Unit4Satellitenavigation——Classification

、HistoryandtheorySatnav=satellite['s?t?la?t]navigation[n?v?'ge??(?)n]衛(wèi)星導(dǎo)航geo-spatial[d?i:???spe???l]地理空間Longitude['l?n(d)??tju:d]經(jīng)度latitude['l?t?tju:d]緯度Transmit[tr?nz'm?t]傳輸Satellite['s?t?la?t]tracking['tr?k??]衛(wèi)星追蹤Synchronisation[s?n?kr?na?'ze??n]同步GNSS=globalnavigationsatellitesystem全球?qū)Ш叫l(wèi)星系統(tǒng)MEO=medium['mi?d??m]Earthorbit

['??b?t]中地球軌道NewWords&PhrasesOrbital['?:b?t(?)l]inclination[?nkl?'ne??(?)n]軌道傾角SBAS=SatelliteBasedAugmentationSystems星基增強(qiáng)系統(tǒng)GBAS=GroundBasedAugmentationSystems地基增強(qiáng)系統(tǒng)WAAS=WideAreaAugmentationSystem廣域增強(qiáng)系統(tǒng)EGNOS=EuropeanGeostationary[d?i??(?)'ste??(?)n(?)r?]NavigationOverlay[??v?'le?]Service歐洲同步衛(wèi)星導(dǎo)航覆蓋服務(wù)MSAS=Multi-FunctionalSatelliteAugmentationSystem多功能衛(wèi)星增強(qiáng)系統(tǒng)LAAS=

LocalAreaAugmentationSystem

局域增強(qiáng)系統(tǒng)NewWords&PhrasesSpectrum['spektr?m]光譜DGPS=Differential[,d?f?'ren?(?)l]GPS差分GPSRTK=RealTimeKinematic[,k?n?'m?t?k]實(shí)時(shí)動(dòng)態(tài)terrestrial

[t?'restr??l]陸地的Deviate['di:v?e?t]偏離Ephemeris[?'fem(?)r?s]星歷表(記錄衛(wèi)星運(yùn)行參數(shù))Atomic[?'t?m?k]clock原子鐘Trilateration[,trail?t?'rei??n]三邊測(cè)量/三球交匯Ionosphere[a?'?n?sf??]電離層NewWords&PhrasesTangent[?t?nd??nt]切線Radionavigation[,re?d???,n?v?'ɡe???n]無(wú)線電導(dǎo)航

compatible[k?m'p?t?b(?)l]兼容的CBOC=Composite['k?mp?z?t]Binary['ba?n?r?]Offset['?fset]Carrier

['k?r??]

復(fù)合二進(jìn)制偏移載波GEO=Geostationary[d?i??(?)'ste??(?)n(?)r?]orbit['?:b?t]對(duì)地靜止軌道GSO=Geosynchronous[,d?i??(?)'s??kr?n?s]orbit地球同步軌道Military['m?l?t(?)r?]軍事的Sensitivity[sens?'t?v?t?]敏感性NewWords&Phrasespseudo-random['sju?d??,'r?nd?m]code偽隨機(jī)碼UHF=Ultra['?ltr?]HighFrequency超高頻Plastic['pl?st?k]塑料的Troposphere['tr?p?(?)sf??]對(duì)流層NewWords&PhrasesA

satellitenavigation

or

satnav

systemisasystemthatuses

satellites

toprovideautonomousgeo-spatialpositioning.Itallowssmall

electronic

receiverstodeterminetheirlocation(longitude,

latitude,and

altitude/elevation)tohighprecision(withinafewmetres)using

timesignals

transmittedalonga

lineofsight

by

radio

fromsatellites.衛(wèi)星導(dǎo)航或衛(wèi)星導(dǎo)航系統(tǒng)是利用衛(wèi)星來(lái)提供自主地理空間定位的系統(tǒng)。它是通過衛(wèi)星發(fā)射無(wú)線電報(bào)時(shí)信號(hào)，并沿直線傳輸，再根據(jù)小型電子接收器確定其位置信息(包括維度、經(jīng)度、高度/海拔高度)，達(dá)到定位的高精度(幾米內(nèi))。Satellite

NavigationThesystemcanbeusedforprovidingposition,navigationorfortrackingthepositionofsomethingfittedwithareceiver(satellitetracking).Thesignalsalsoallowtheelectronicreceivertocalculatethecurrentlocaltimetohighprecision,whichallowstimesynchronisation.Satnavsystemsoperateindependentlyofanytelephonicorinternetreception,thoughthesetechnologiescanenhancetheusefulnessofthepositioninginformationgenerated.該系統(tǒng)可用于提供位置、導(dǎo)航或跟蹤裝有接收機(jī)的物體的位置（衛(wèi)星跟蹤）。電子接收器可以對(duì)當(dāng)?shù)貢r(shí)間進(jìn)行校準(zhǔn)來(lái)提高信號(hào)的精度，使得時(shí)間同步。衛(wèi)星導(dǎo)航系統(tǒng)獨(dú)立于任何電話或互聯(lián)網(wǎng)接收操作，盡管這些技術(shù)可以增強(qiáng)定位信息的有用性。Satellite

NavigationAsatellitenavigationsystemwithglobalcoveragemaybeknownasa

globalnavigationsatellitesystem

(GNSS).AsofDecember2016,onlythe

UnitedStates'

GlobalPositioningSystem

(GPS),Russia's

GLONASSandthe

EuropeanUnion‘s

Galileo

areglobaloperationalGNSSs.具有全球覆蓋范圍的衛(wèi)星導(dǎo)航系統(tǒng)可稱為全球?qū)Ш叫l(wèi)星系統(tǒng)(GNSS)。截至2016年12月，只有美國(guó)的全球定位系統(tǒng)(GPS)，俄羅斯的GLONASS（格洛納斯）和歐盟的Galileo（伽利略）系統(tǒng)是全球運(yùn)行的GNSS。Satellite

NavigationTheEuropeanUnion’sGalileoGNSSisscheduledtobefullyoperationalby2020.

China

isintheprocessofexpandingitsregional

BeiDouNavigationSatelliteSystem

intotheglobal

BeiDou-2GNSS

by2020.India,

France

and

Japan

areintheprocessofdevelopingregionalnavigationandaugmentationsystemsaswell.歐盟伽利略全球?qū)Ш叫l(wèi)星系統(tǒng)計(jì)劃到2020年全面運(yùn)行。到2020年，中國(guó)的區(qū)域性北斗導(dǎo)航衛(wèi)星系統(tǒng)也將擴(kuò)展到全球性的北斗2號(hào)全球?qū)Ш叫l(wèi)星系統(tǒng)。印度、法國(guó)和日本也在開發(fā)區(qū)域?qū)Ш胶驮鰪?qiáng)系統(tǒng)。Satellite

NavigationGlobalcoverageforeachsystemisgenerallyachievedbya

satelliteconstellation

of18–30

mediumEarthorbit

(MEO)satellitesspreadbetweenseveral

orbitalplanes.Theactualsystemsvary,butuse

orbitalinclinations

of>50°and

orbitalperiods

ofroughlytwelvehours(atanaltitudeofabout20,000kilometresor12,000miles).每個(gè)系統(tǒng)的全球覆蓋通常是由18至30顆中地球軌道(MEO)衛(wèi)星組成的衛(wèi)星星座實(shí)現(xiàn)的，這些衛(wèi)星分布在幾個(gè)軌道平面之間。實(shí)際系統(tǒng)各不相同，但使用的軌道傾角大于50°，軌道周期約為12小時(shí)(高度約20000公里或12000英里)。Satellite

NavigationSatellitenavigationsystemsthatprovideenhancedaccuracyandintegritymonitoringusableforcivilnavigationareclassifiedasfollows:GNSS-1isthefirstgenerationsystemandisthecombinationofexistingsatellitenavigationsystems(GPSandGLONASS),with

SatelliteBasedAugmentationSystems

(SBAS)or

GroundBasedAugmentationSystems

(GBAS).Part1----ClassificationIntheUnitedStates,thesatellitebasedcomponentisthe

WideAreaAugmentationSystem

(WAAS),inEuropeitisthe

EuropeanGeostationaryNavigationOverlayService

(EGNOS),andinJapanitisthe

Multi-FunctionalSatelliteAugmentationSystem

(MSAS).Groundbasedaugmentationisprovidedbysystemslikethe

LocalAreaAugmentationSystem

(LAAS).GNSS-2

isthesecondgenerationofsystemsthatindependentlyprovidesafullciviliansatellitenavigationsystem,exemplifiedbytheEuropeanGalileopositioningsystem.Part1----ClassificationThesesystemswillprovidetheaccuracyandintegritymonitoringnecessaryforcivilnavigation;includingaircraft.ThissystemconsistsofL1andL2frequencies(inthe

Lband

oftheradiospectrum)forciviluseandL5forsystemintegrity.DevelopmentisalsoinprogresstoprovideGPSwithciviluseL2andL5frequencies,makingitasystem.這些系統(tǒng)將提供民用導(dǎo)航所必需的準(zhǔn)確性和完整性監(jiān)測(cè)；包括飛行器。該系統(tǒng)由L1和L2頻率段組成（在無(wú)線電頻譜的L波段），用于民用，L5頻率段用于系統(tǒng)完整性。民用L2和L5頻率在GPS的應(yīng)用尚在開發(fā)，使之成為GNSS-2系統(tǒng)。Part1----ClassificationCoreSatellitenavigationsystems,currentlyGPS(UnitedStates),GLONASS(RussianFederation),Galileo(EuropeanUnion)andBeiDouNavigationSatelliteSystem(BDS,China).GlobalSatelliteBasedAugmentationSystems(SBAS)suchasOmnistarandStarFire.RegionalSBASincludingWAAS(US),EGNOS(EU),MSAS(Japan)andGAGAN(India).RegionalscaleGBASsuchasCORSnetworks.Part1----ClassificationRegionalSatelliteNavigationSystemssuchasChina'sBeidou,India'sNAVIC,andJapan'sproposedQZSS.ContinentalscaleGroundBasedAugmentationSystems(GBAS)forexampletheAustralianGRASandthejointUSCoastGuard,CanadianCoastGuard,USArmyCorpsofEngineersandUSDepartmentofTransportationNationalDifferentialGPS(DGPS)service.LocalGBAStypifiedbyasingleGPSreferencestationoperatingRealTimeKinematic(RTK)corrections.Part1----ClassificationGroundbased

radionavigation

haslongbeenpracticed.The

DECCA,LORAN,GEE

and

Omega

systemsusedterrestrial

longwave

radio

transmitters

whichbroadcastaradiopulsefromaknown"master"location,followedbyapulserepeatedfromanumberof"slave"stations.臺(tái)卡、羅蘭、奇(GEE)和歐米伽系統(tǒng)使用地面長(zhǎng)波無(wú)線電發(fā)射機(jī)，從已知的“主”位置發(fā)射無(wú)線電脈沖，并跟隨若干重復(fù)脈沖。Part2—HistoryandtheoryThedelaybetweenthereceptionofthemastersignalandtheslavesignalsallowedthereceivertodeducethedistancetoeachoftheslaves,providinga

fix.主信號(hào)和從信號(hào)的接收之間的延遲使得接收機(jī)能夠推斷到每個(gè)從信號(hào)之間的距離，從而提供一個(gè)確定值。Thefirstsatellitenavigationsystemwas

Transit,asystemdeployedbytheUSmilitaryinthe1960s.Transit'soperationwasbasedonthe

Dopplereffect:thesatellitestravelledonwell-knownpathsandbroadcasttheirsignalsonawell-known

radiofrequency.Part2—HistoryandtheoryThereceivedfrequencywilldifferslightlyfromthebroadcastfrequencybecauseofthemovementofthesatellitewithrespecttothereceiver.Bymonitoringthisfrequencyshiftoverashorttimeinterval,thereceivercandetermineitslocationtoonesideortheotherofthesatellite,andseveralsuchmeasurementscombinedwithapreciseknowledgeofthesatellite'sorbitcandetermineaparticularposition.由于衛(wèi)星相對(duì)于接收機(jī)的移動(dòng)，接收頻率將與發(fā)射頻率略有不同。通過在短時(shí)間內(nèi)監(jiān)測(cè)這一頻率變化接收器可以確定它在衛(wèi)星的一邊或另一邊的位置，而幾個(gè)這樣的測(cè)量，再加上衛(wèi)星軌道的精確知識(shí)，就可以確定詳細(xì)的位置。Part2—HistoryandtheoryPartofanorbitingsatellite'sbroadcastincludeditspreciseorbitaldata.Inordertoensureaccuracy,the

USNavalObservatory(USNO)

continuouslyobservedthepreciseorbitsofthesesatellites.Asasatellite'sorbitdeviated,theUSNOwouldsendtheupdatedinformationtothesatellite.Subsequentbroadcastsfromanupdatedsatellitewouldcontainitsmostrecent

ephemeris.軌道衛(wèi)星廣播的一部分包括其精確的軌道數(shù)據(jù)。為了保證精確性，美國(guó)海軍天文臺(tái)(USNO)不斷觀測(cè)這些衛(wèi)星的精確軌道。當(dāng)衛(wèi)星的軌道偏離時(shí)，USNO將向衛(wèi)星發(fā)送更新的信息。隨后從更新的衛(wèi)星廣播將包含其最近的星歷表（記錄衛(wèi)星運(yùn)行參數(shù)）。Part2—HistoryandtheoryModernsystemsaremoredirect.Thesatellitebroadcastsasignalthatcontainsorbitaldata(fromwhichthepositionofthesatellitecanbecalculated)andtheprecisetimethesignalwastransmitted.現(xiàn)代系統(tǒng)更直接。衛(wèi)星廣播一個(gè)包含軌道數(shù)據(jù)的信號(hào)(衛(wèi)星的位置可以從該數(shù)據(jù)中計(jì)算)，以及信號(hào)發(fā)送的精確時(shí)間。Theorbital

ephemeris

istransmittedinadatamessagethatissuperimposedonacodethatservesasatimingreference.軌道星歷表作為時(shí)間基準(zhǔn)，傳輸?shù)氖堑臄?shù)據(jù)編碼。Part2—HistoryandtheoryThesatelliteusesan

atomicclock

tomaintainsynchronizationofallthesatellitesintheconstellation.Thereceivercomparesthetimeofbroadcastencodedinthetransmissionofthree(atsealevel)orfourdifferentsatellites,therebymeasuringthetime-of-flighttoeachsatellite.Severalsuchmeasurementscanbemadeatthesametimetodifferentsatellites,allowingacontinualfixtobegeneratedinrealtimeusinganadaptedversionof

trilateration.衛(wèi)星使用原子鐘來(lái)保持星座中所有衛(wèi)星的同步。接收機(jī)通過比較三顆或是四顆不同的衛(wèi)星(相對(duì)于海平面)傳輸編碼的廣播時(shí)間。從而測(cè)量每顆衛(wèi)星的渡越時(shí)間。這樣的測(cè)量可以同時(shí)對(duì)不同的衛(wèi)星進(jìn)行，可通過適當(dāng)?shù)娜厹y(cè)量來(lái)進(jìn)行連續(xù)實(shí)時(shí)地修正。Part2—HistoryandtheoryEachdistancemeasurement,regardlessofthesystembeingused,placesthereceiveronasphericalshellatthemeasureddistancefromthebroadcaster.Bytakingseveralsuchmeasurementsandthenlookingforapointwherethey