对载波跟踪混合DS 跳频扩频测控系统的研究-外文翻译

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

2、hetrackingloopwillshifttothefrequencystepresponsestateceaselesslyandthemeasurementresolutionseverelydecline,eventheloopislikelytobeunlocked.Thispaperpresentsacarriertrackingloopaidedbyfrequencyhoppingpattern.Inordertokeepthestabilityofthetrackingloop,theDopplerfrequencyagilityinthenextfrequencyh

3、oppingdwellisestimatedandtimelycompensatedtothefrequencyadjustmentofcarrierNCOaccordingtothepresetfrequencyhoppingpatternandcurrentspacecraftvelocity.Simulationresultsshowthatthismethodeffectivelyeliminatestheinstabilityduetocarrierfrequencyhopping,andtheresolutionofloopmeetstherequirementofTT&C

4、system.Keywords：carriertracking；DS/FHSS；frequencyagility；aided；TT&CIResearchonCarrierTrackinginHybridDS/FHSpreadSpectrumTT&CSystemI．INTRODUCTIONThemainfunctionofTT&C(Telemetry,TrackingandCommand)systemisrangingandvelocitymeasurement.Presently,themostcommonusedTT&Csystemsareunitcarriersystemandun

5、itspreadspectrumsystem.FortheunitcarrierTT&Csystem,rangingisrealizedbymeasuringthephasedifferencebetweentransmittedandreceivedtones,andfortheunitspreadspectrumTT&Csystem,accordingtotheautocorrelationpropertiesofPNcode,rangingisrealizedbymeasuringthephasedelaybetweenthereceivedandlocalpseudonoise

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

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