欢迎来到天天文库
浏览记录
ID:58195049
大小:10.42 MB
页数:29页
时间:2020-09-05
《GPS是怎样工作的课件.ppt》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、StudentSupportServicesByAndyWilliamsonHowGPSWorksWhatisGPS?GPS,whichstandsforGlobalPositioningSystem,istheonlysystemtodayabletoshowyouyourexactpositionontheEarthanytime,inanyweather,anywhere.ThethreepartsofGPSare:SatellitesReceiversSoftwareWhatisGPS?Isalocatio
2、nsystembasedonaconstellationof24satellitesorbitingtheearthataltitudesofapproximately11,000miles.CanaccuratelydeterminelocationsofHistoryInitiatedbyU.S.DepartmentofDefenseMilitaryplannerswantedatechnologywhereapositioncouldbeobtainedwithouttheuseofradiotransmis
3、sionsOfficiallynamedNavigationSystemwithTimingandRanging(NAVSTAR)Firstsatellitelaunchedin1974(satellitesbyRockwellCollins)SatellitesTherearequiteanumberofsatellitesoutthereinspace.Theyareusedforawiderangeofpurposes:satelliteTV,cellularphones,militarypurposesan
4、detc.SatellitescanalsobeusedbyGPSreceivers.GPSSatellitesTheGPSOperationalConstellationconsistsof24satellitesthatorbittheEarthinverypreciseorbitstwiceaday.GPSsatellitesemitcontinuousnavigationsignals.ReceiversandSatellitesGPSunitsaremadetocommunicatewithGPSsate
5、llites(whichhaveamuchbetterviewoftheEarth)tofindoutexactlywheretheyareontheglobalscaleofthings.GPSSignalsEachGPSsatellitetransmitsdatathatindicatesitslocationandthecurrenttime.AllGPSsatellitessynchronizeoperationssothattheserepeatingsignalsaretransmittedatthes
6、ameinstant.Physicallythesignalisjustacomplicateddigitalcode,orinotherwords,acomplicatedsequenceof“on”and“off”pulses.PseudoRandomNoiseCodeReceiverPRNSatellitePRNTimeDifferenceTimeDifferenceTheGPSreceivercomparesthetimeasignalwastransmittedbyasatellitewiththetim
7、eitwasreceived.ThetimedifferencetellstheGPSreceiverhowfarawaythesatelliteis.CalculatingDistanceVelocityxTime=DistanceRadiowavestravelatthespeedoflight,roughly186,000milespersecond(mps)Ifittook0.06secondstoreceiveasignaltransmittedbyasatellitefloatingdirectlyov
8、erhead,usethisformulatofindyourdistancefromthesatellite.186,000mpsx0.06seconds=11,160milesTriangulationGeometricPrinciple:Youcanfindonelocationifyouknowitsdistancefromother,already
此文档下载收益归作者所有