对载波跟踪混合DS 跳频扩频测控系统的研究摘要-毕业论文外文翻译

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1、AbstractResearchonCarrierTrackinginHybridDS/FHSpreadSpectrumTT&CSystemAbstractBecauseoftheeffectofcarrierfrequencyhopping,theinputIFsignalofcarriertrackingloopinDS/FHSS(DirectSequence/FrequencyHoppingSpreadSpectrum)TT&C(Telemetry,Tracking&Command)SystemischaracterizedbytheDopplerfrequencya

2、gile.Thetrackingloopwillshifttothefrequencystepresponsestateceaselesslyandthemeasurementresolutionseverelydecline,eventheloopislikelytobeunlocked.Thispaperpresentsacarriertrackingloopaidedbyfrequencyhoppingpattern.Inordertokeepthestabilityofthetrackingloop,theDopplerfrequencyagilityinthene

3、xtfrequencyhoppingdwellisestimatedandtimelycompensatedtothefrequencyadjustmentofcarrierNCOaccordingtothepresetfrequencyhoppingpatternandcurrentspacecraftvelocity.Simulationresultsshowthatthismethodeffectivelyeliminatestheinstabilityduetocarrierfrequencyhopping,andtheresolutionofloopmeetsth

4、erequirementofTT&Csystem.Keywords：carriertracking；DS/FHSS；frequencyagility；aided；TT&CResearchonCarrierTrackinginHybridDS/FHSpreadSpectrumTT&CSystemI．INTRODUCTIONThemainfunctionofTT&C(Telemetry,TrackingandCommand)systemisrangingandvelocitymeasurement.Presently,themostcommonusedTT&Csystemsar

5、eunitcarriersystemandunitspreadspectrumsystem.FortheunitcarrierTT&Csystem,rangingisrealizedbymeasuringthephasedifferencebetweentransmittedandreceivedtones,andfortheunitspreadspectrumTT&Csystem,accordingtotheautocorrelationpropertiesofPNcode,rangingisrealizedbymeasuringthephasedelaybetweent

6、hereceivedandlocalpseudonoise(PN)code.VelocitymeasurementinbothofTT&CsystemsdependsonextractingthefrequencydifferenceresultingfromtheDopplerphenomenabetweenthetransmittedandreceivedcarrier.Whilealltheprocessesmentionedabovearefinishedonthegroundofhighresolutioncarriertracking,andthephaselo

7、ckloopisthecommonusedmethodtoimplementitinTT&Csystem.Asthespaceelectromagnetismenvironmentbecomemoreandmorecomplicated,thecapabilityofanti-jammingisrequiredbythefutureTT&Csystem[1].SoweconsiderusingthehybridDS/FHSS(DirectSequence/FrequencyHoppingSpreadSpectrum