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1、山东建筑大学毕业论文外文文献及译文本科毕业论文外文文献及译文文献、资料题目：GlobalPositioningSystem文献、资料来源：http://en.wikipedia.org/wiki/Global_Positioning_System文献、资料发表（出版）日期：2009.01.03院（部）：土木工程学院专业：土木工程班级：测绘052姓名：唐海国学号：2005011047指导教师：郭秋英翻译日期：2009.5.19-48-山东建筑大学毕业论文外文文献及译文外文文献：GlobalPositioningSystemTheGlobalPositioning
2、System(GPS)isaglobalnavigationsatellitesystem(GNSS)developedbytheUnitedStatesDepartmentofDefenseandmanagedbytheUnitedStatesAirForce50thSpaceWing.ItistheonlyfullyfunctionalGNSSintheworld,canbeusedfreely,andisoftenusedbyciviliansfornavigationpurposes.TheGlobalPositioningSystem(GPS)isa
3、satellite-basednavigationsystemmadeupofanetworkof24satellitesplacedintoorbitbytheU.S.DepartmentofDefense.GPSwasoriginallyintendedformilitaryapplications,butinthe1980s,thegovernmentmadethesystemavailableforcivilianuse.GPSworksinanyweatherconditions,anywhereintheworld,24hoursaday.Ther
4、earenosubscriptionfeesorsetupchargestouseGPS.Itusesaconstellationofbetween24and32mediumEarthorbitsatellitesthattransmitpreciseradiowavesignals,whichallowGPSreceiverstodeterminetheircurrentlocation,thetime,andtheirvelocity.ItsofficialnameisNAVSTARGPS.AlthoughNAVSTARisnotanacronym,[1]
5、afewbackronymshavebeencreatedforit.Sinceitbecamefullyoperationalin1993,GPShasbecomeawidelyusedaidtonavigationworldwide,andausefultoolformap-making,landsurveying,commerce,scientificuses,andhobbiessuchasgeocaching.Also,theprecisetimereferenceisusedinmanyapplicationsincludingthescienti
6、ficstudyofearthquakesandasarequiredtimesynchronizationmethodforcellularnetworkprotocolssuchastheIS-95standardforCDMA.GPSsatellitescircletheearthtwiceadayinaverypreciseorbitandtransmitsignalinformationtoearth.GPSreceiverstakethisinformationandusetriangulationtocalculatetheuser'sexact
7、location.Essentially,theGPSreceivercomparesthetimeasignalwastransmittedbyasatellitewiththetimeitwasreceived.ThetimedifferencetellstheGPSreceiverhowfarawaythesatelliteis.Now,withdistancemeasurementsfromafewmoresatellites,thereceivercandeterminetheuser'spositionanddisplayitontheunit's
8、electronicmap.AGPSr
