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ID:239110
大小:363.97 KB
页数:25页
时间:2017-07-12
《毕业论文外文翻译-对载波跟踪混合DS 跳频扩频测控系统的研究》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、AbstractResearchonCarrierTrackinginHybridDS/FHSpreadSpectrumTT&CSystemAbstractBecauseoftheeffectofcarrierfrequencyhopping,theinputIFsignalofcarriertrackingloopinDS/FHSS(DirectSequence/FrequencyHoppingSpreadSpectrum)TT&C(Telemetry,Tracking&Command)Systemischaracterizedbyth
2、eDopplerfrequencyagile.Thetrackingloopwillshifttothefrequencystepresponsestateceaselesslyandthemeasurementresolutionseverelydecline,eventheloopislikelytobeunlocked.Thispaperpresentsacarriertrackingloopaidedbyfrequencyhoppingpattern.Inordertokeepthestabilityofthetrackinglo
3、op,theDopplerfrequencyagilityinthenextfrequencyhoppingdwellisestimatedandtimelycompensatedtothefrequencyadjustmentofcarrierNCOaccordingtothepresetfrequencyhoppingpatternandcurrentspacecraftvelocity.Simulationresultsshowthatthismethodeffectivelyeliminatestheinstabilityduet
4、ocarrierfrequencyhopping,andtheresolutionofloopmeetstherequirementofTT&Csystem.Keywords:carriertracking;DS/FHSS;frequencyagility;aided;TT&CIResearchonCarrierTrackinginHybridDS/FHSpreadSpectrumTT&CSystemI.INTRODUCTIONThemainfunctionofTT&C(Telemetry,TrackingandCommand)syste
5、misrangingandvelocitymeasurement.Presently,themostcommonusedTT&Csystemsareunitcarriersystemandunitspreadspectrumsystem.FortheunitcarrierTT&Csystem,rangingisrealizedbymeasuringthephasedifferencebetweentransmittedandreceivedtones,andfortheunitspreadspectrumTT&Csystem,accord
6、ingtotheautocorrelationpropertiesofPNcode,rangingisrealizedbymeasuringthephasedelaybetweenthereceivedandlocalpseudonoise(PN)code.VelocitymeasurementinbothofTT&CsystemsdependsonextractingthefrequencydifferenceresultingfromtheDopplerphenomenabetweenthetransmittedandreceived
7、carrier.Whilealltheprocessesmentionedabovearefinishedonthegroundofhighresolutioncarriertracking,andthephaselockloopisthecommonusedmethodtoimplementitinTT&Csystem.Asthespaceelectromagnetismenvironmentbecomemoreandmorecomplicated,thecapabilityofanti-jammingisrequiredbythefu
8、tureTT&Csystem[1].SoweconsiderusingthehybridDS/FHSS(DirectSequence/FrequencyHoppingSpreadSpectru
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