衛(wèi)星信號接收機中關鍵電路的研究與實現(xiàn).pdf

1、華中科技大學碩士學位論文衛(wèi)星信號接收機中關鍵電路的研究與實現(xiàn)姓名：高原申請學位級別：碩士專業(yè)：電磁場與微波技術指導教師：張祖蔭2002.10.28華中科技大學碩士學位論文_IIIIIlillII____ABSTRACTGPSsatellitenavigationsystemiswidelyusedinfieldsofpositioning，navigationandgeologicalmappingforitshighefficienc

2、ylowcostandexcellentperformanceInordertOimprovethenavigationprecisionbaseonthecurrentGPSsystem，manymethodshavebeenbroughtabout，thewidearetttdifferenceGPS(WADGPS)systemisoneofthemThroughsimultaneouslyreceivingGPSsignaland

3、theerrorcorrectionsignalbroadcasted坶搬estations，WADGPScanimprovethepositioningprecisiondramaticallySincethistechniquehastheadvantagesoflowcostandhighperformance，itwilldefinitelyhaveabn【ghtfutureInthisarticle，theauthorpres

4、entstheoperationalprinciples，designtheoriesandmethodologiesofthekeycomponentsintheWADGPSsatellitesignalreceiverThemaincontentofthearticlecanbedividedinto3pans：f1)ThestudyofthestructureofwirelesscommunicationreceiverSever

5、alkindsofthereceiverstructureareanalyzed，remarkableemphasisispaidonthepros&consofthesestructuresinthepracticaluseAnalyzedtheimpactofRFfrontendsensitivityandnoisefiguretOtheoverallperformanceofthesystem(2)Thestudyofthesyn

6、chronizationinthedirectspreadspectrumsystemItcarlbedividedinto2partsthesynchronizationofthepseudonoisecodeandthesynchronizationofthecarrierThesynchronizationofthePNcodeincludesthecapture，verification，tracking3stepsWefirs

7、tstudythebasictheoriesofthesesteps，analyzingthefeasibilityofcodesynchronizationwiththeexistenceoffrequencyoffset，thensimulatedtheperformanceofschemeinSystemView45finallythesefunctionmodules繼implementedinFPGAwithVHDLAcarr

8、ierrecoveryschemeforOQPSKmodulationmodeisalsoproposed，whichincludesthefrequencycaptureandthephasetracking2pansTheauthorfirstdeducedtheexpressionusedtoguidethisschemeandthentestifiedtheefficienciesandtherobustnessofthesys

9、teminSystemview45(3)ThestudyoftheerrorcorrectingcodeusedinwirelesscommunicationWefirstanalyzedthebasictheoriesoftheconvolutionalcodeanditsmaximamlikelihooddecodingAfterthedetaileddiscussofViterbidecodingalgorithm，theauth