测绘类外文资料翻译--自动定位技术

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1、中文6460字毕业设计（论文）外文资料原文与翻译院系：专业班级：学号：学生姓名：指导老师：AutomaticPositionDetermination1PositionDeterminationThetraditionalmethodforthedirectdeterminationofpositionhasbeenbyastronomicalobservation.Therelativepositionsandmovementsofthestarsaswellcataloguedandsowithac

2、ombinationofaltitude,directionandtimeobservationstothestars,thepositionintermsoflatitudeandlongitudeofagroundstationcanbecalculated.Thereiflesscallfordirectpositiondeterminationnowadayssincemostcountriesarecoveredbyaprimaryhorizontalcontrolscheme,andthea

3、bsolutepositionofanynewlocalsurveywordcanbeestablishedbyincludinganationalreferencepointinthelocalsurvey.Inveryremoteareas,orwheretheterrainistotallyunsuitablefortheclassicsurveymethodsoftriangulationandtraverse,thereis,however,aneedfordirectpositiondete

4、rmination.Forthemajorityofthiswork,visualobservationtothestarshasbeenreplacedbyelectromagneticmeasurementstoorfromartificialearthsatellites.Inaddition,therelativepositionsofsurveystationscanbedetermineddirectlybyinertialtechniquesoriginallydevelopedforai

5、rcraftnavigation.1.1InertialPositioningApairofgyrosareincorporatedinapositionfixingdeviceknownastheAuto-SurveyormanufacturedbyLittonSystems.Ithasoriginatedfromanaircraftnavigationsystem,whichwasdevelopedformilitaryapplicationsintoitspresentthree-dimensio

6、nalsurveysystem.‘Hardware’consistsof(i)theinertialmeasuringunit,(ii)acomputer,(iii)acassetterecorder,(iv)adisplayandcontrolunitand(v)thepowersupply.Theseitemscanbeplacedanywherewithinaroadvehicleorhelicopterprovidingthattheoperatoriscloseto(iv).Themeasur

7、ingunitcontainsagyro-stabilizedplatformwithtwoair-bearinggyroscopesinfourgimbalmountingswhichkeepitsthreeorthogonalaxisorientedinspaceinanorth-east=downwardsrelationship.Eachaxisalsohasasensor-torquertypeofacclerometerwhichdefinesaccelerationintheparticu

8、lardirectionviaaquantitizersystemfeedingthecomputer.Thisispre-programmedtocomputethesurveyasitiscarriedoutandtocontrolthesystem(seeFig.1)Beforestaringthesurveyanalignmentdrillcarriedoutattheoriginstation.Thisissaidtohavead