对载波跟踪混合DS 跳频扩频测控系统的研究-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-毕业论文外文翻译》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)Systemischar

2、acterizedbytheDopplerfrequencyagile.Thetrackingloopwillshifttothefrequencystepresponsestateceaselesslyandthemeasurementresolutionseverelydecline,eventheloopislikelytobeunlocked.Thispaperpresentsacarriertrackingloopaidedbyfrequencyhoppingpattern.Inordertokeept

3、hestabilityofthetrackingloop,theDopplerfrequencyagilityinthenextfrequencyhoppingdwellisestimatedandtimelycompensatedtothefrequencyadjustmentofcarrierNCOaccordingtothepresetfrequencyhoppingpatternandcurrentspacecraftvelocity.Simulationresultsshowthatthismethod

4、effectivelyeliminatestheinstabilityduetocarrierfrequencyhopping,andtheresolutionofloopmeetstherequirementofTT&Csystem.Keywords：carriertracking；DS/FHSS；frequencyagility；aided；TT&CIResearchonCarrierTrackinginHybridDS/FHSpreadSpectrumTT&CSystemI．INTRODUCTIONThem

5、ainfunctionofTT&C(Telemetry,TrackingandCommand)systemisrangingandvelocitymeasurement.Presently,themostcommonusedTT&Csystemsareunitcarriersystemandunitspreadspectrumsystem.FortheunitcarrierTT&Csystem,rangingisrealizedbymeasuringthephasedifferencebetweentransmi

6、ttedandreceivedtones,andfortheunitspreadspectrumTT&Csystem,accordingtotheautocorrelationpropertiesofPNcode,rangingisrealizedbymeasuringthephasedelaybetweenthereceivedandlocalpseudonoise(PN)code.VelocitymeasurementinbothofTT&Csystemsdependsonextractingthefrequ

7、encydifferenceresultingfromtheDopplerphenomenabetweenthetransmittedandreceivedcarrier.Whilealltheprocessesmentionedabovearefinishedonthegroundofhighresolutioncarriertracking,andthephaselockloopisthecommonusedmethodtoimplementitinTT&Csystem.Asthespaceelectroma

8、gnetismenvironmentbecomemoreandmorecomplicated,thecapabilityofanti-jammingisrequiredbythefutureTT&Csystem[1].SoweconsiderusingthehybridDS/FHSS(DirectSequence/FrequencyHoppingSpreadSpectru