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25 April 2016, Volume 36 Issue 2 Previous Issue    Next Issue

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InvestigationoflightconcentratingmodeforSSPS ZHANG Xing-Hua, HOU Xin-Bin, WANG Li, YAN Yong 2016, 36 (2):  1.  doi: 10.16708/j.cnki.1000-758X.2016.0019 Abstract ( 875 )   PDF (5018KB) ( 1722 )   Save Spacesolarpowerstation（SSPS）isaspacesystemcollectingandtransformingsolarenergyintomicrowaveorlaserintheorbitandwirelesslytransmittingthepowertothegroundstation,wherethepowerischangedintoelectricity.Solarconcentrationisamethodofcollectingspacesolarenergy,andisappliedto  manySSPSconcepts.AfterreviewingtheprogressofthesolarconcentratingSSPS,andsummarizingtheconceptsandtechnologiesofsolarconcentrationrelatedtotheSSPS,thesolarconcentrationisdividedintofourmodescorrespondingtothreelevels,andboththeadvantagesanddisadvantagesofeachmodewereanalyzed.ThedevelopmentofthesolarconcentratingSSPSwasproposed. Related Articles | Metrics

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Anamplitudephasemeasurementmethodforbeamformingnetworkwithnonorthogonalcodes GAO Yuan, AN Jian-Ping, ZHOU Hui, HAO Shi-Guang, CHAI Yuan 2016, 36 (2):  13.  doi: 10.16708/j.cnki.1000-758X.2016.0021 Abstract ( 861 )   PDF (1894KB) ( 868 )   Save Theapplicationofanamplitudeandphasemeasurementsystembasedonthespreadingcodesislimitedbytherequirementsofcodeorthogonality.Anamplitudephasemeasurementmethodfordigitalbeamformingnetworkbasedonnonorthogonalcodeswasproposedtoovercomethelimitation.Themainsourceoferrorsinthemeasurementsystemwithnonorthogonalcodeswasmultipleaccessinterference(MAI).Therefore,decorrelatingalgorithmwasproposedtosuppresstheMAIatthecostofincreasingthenoiseslightly.Theoreticalanalysisprovidedthetheorylowerboundoftheamplitudeandphasemeasurementandtheeffectofthesystemerrorandmutualcouplingonthemeasurementaccuracy.Simulationresultsdemonstratethattheaccuracyofthemeasurementsystemwithoutdecorrelatingalgorithmisunacceptable.However,theproposedmethodcansatisfytheaccuracyrequirementsof±01dBand±1degreeundertheconditionsthattheinbandsignaltonoiseratio(SNR)ishigherthan10dB.Moreover,thesimulationresultsareingoodagreementwiththoseoftheoreticalanalysis. Related Articles | Metrics

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SimulationandresearchonRAIMalgorithmbuiltincivilaviationairbornereceiverbasedonBeiDousatellitesystems LIU Rui-Hua, DENG Ming-Zhi, WEI Bao-Guo, XING Zhao-Dong 2016, 36 (2):  20.  doi: 10.16708/j.cnki.1000-758X.2016.0022 Abstract ( 1284 )   PDF (4379KB) ( 1184 )   Save Receiverautonomousintegritymonitoring(RAIM)algorithmisalreadymatureintheory.ButastoBeiDounavigationsatellitesystem(BDS),thereisrareanalysisabouttheperformanceofRAIMwiththeobserveddata.AccordingtotheconstellationstatusofBDSsystemandtheperformanceofopenservice,basedontherequirementofnonprecisionapproachincivilaviationfield,thesimulationandresearchonRAIMwerepresented.Firstly,theavailabilityofRAIMinAsiaPacificwascalculated.Then,thefunctionandcapabilityoffailuredetectionandidentificationwiththeobserveddatafromNovAtelreceiverwereanalyzedindifferentscenesandfaulttypes.Thesimulationresultsshowthattheaverageofvisiblesatelliteismorethan7,andtheHPLvaluesarelessthan500meters.Furthermore,themeasuredresearchshowsthattheRAIMcandetecttheanomalypseudorange.Thatistosay,BDSsystemmettheneedsoftheRAIM.TheconclusionisthattheBDSissuitableforRAIM,andcanprovidetherequirednavigationperformance(RNP)fornonprecisionapproach(NPA)inthecivilaviationfield. Related Articles | Metrics

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Worstcaseresponsetimeanalysisofmultilevelinterruptsystems YU Guang-Liang, YANG Meng-Fei, XU Jian, JIANG Hong 2016, 36 (2):  28.  doi: 10.16708/j.cnki.1000-758X.2016.0003 Abstract ( 960 )   PDF (1101KB) ( 987 )   Save Acomputationmodelintegratedwithinterruptsandtaskswaspresentedfortheanalysisofworstcaseresponsetime(WCRT)foranaerospaceembeddedsystemwithmultilevelinterrupts.Bothinterruptsandtaskswasusedforaunifiedprioritydefinitioninthismodel,sothetiminganalysisofnestedinterruptscanbecombinedwithtaskresponsetimeanalysistechniques.TheWCRTofbothinterruptsandtaskswasderivedintheintegratedmodel.Furthermore,detaileddescriptionsofkeyparameterswereproposedandthedifferencesbetweeninterruptsandtaskswerealsodiscussed.TheopensourceLEON3processorplatformandModelsimsoftwarewereintroducedtosimulateandverifythemethod.TheresultsshowthattheoverestimateoftaskWCRTislessthan5%whichdemonstratestheeffectivenessofthemethodandthevalueforengineeringapplications. Related Articles | Metrics

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HighprecisionmicronanosatelliteformationkeepingbasedonSiCMEMSmicrothrusterarray FAN Lin-Dong, YANG Bo, MIAO Jun, LONG Jun, LIU Xu-Hui 2016, 36 (2):  37.  doi: 10.16708/j.cnki.1000-758X.2016.0002 Abstract ( 842 )   PDF (1803KB) ( 1180 )   Save Withthedevelopmentofthemicro/nanosatellites,theproblemofthestationcontrolneedstobesolved.Thetraditionalpropulsiontechnologycan′tmeettherequirementsofhighprecision.Therefore,theSiCMEMSMicrothrusterarraywasproposedfortheformationkeepingofthemicro/nanosatellites.Consideringthedifferentcharacteristicsofthearrayfromthetraditionalthruster,theinputandoutputmodelwasestablishedandtheinstantaneouspulsecontrolstrategywaspresentedtokeeptheformation.Thesimulationresultsshowthatthearraycanbeappliedtotheneardistanceformationofmicro/nanosatellites,andithasahighpositionaccuracyof3mm.Inaddition,thethrusters′consumptionandcontrolprecisioninfluencedbythesinglethrusterchargeandcontrollerparameterswereanalyzed.Whentheimpulseofthesinglethrusterrangeis8×10-6~20×10-6N·s，itcangetgoodcontrol. Related Articles | Metrics

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Directcouplingmatrixsynthesistechniqueforfilterswithnonresonatingnodes LIU Hao, LI Sheng-Xian 2016, 36 (2):  46.  doi: 10.16708/j.cnki.1000-758X.2016.0023 Abstract ( 965 )   PDF (1537KB) ( 1927 )   Save Animproveddirectcouplingmatrixsynthesistechniquewaspresentedbasedonthetheoryofnonresonatingnodes.Bytreatingnonresonatingnodesasresonatingnodes,thecouplingmatrixwasobtainedusingthecanonicalsynthesis.Thensimilartransformwasconductedto  thematrixsothattheelementscorrespondingtothelocationofnonresonatingnodescontainnoinformationontransmissionzeros.〖JP2〗Andproportionaltransformwasconductedtotherowsandcolumnsoftheelements,sothefilternetworkincludednonresonatingnodesagain.Thenthematrixwhichmaybeusedtodesignthefilterswithnonresonatingnodeswasobtained.Themethodsimplifiesthesynthesis，reconfigurationandsimulationoffilterswithnonresonatingnodes.SimulationresultsinMATLABandHFSSprovethesynthesistechniquereasonableandfeasible. Related Articles | Metrics

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Anewdefinitionevaluationmethodforremotesensingimagesofsatellite TAN Wei, YANG Bing-Xin, HE Hong-Yan 2016, 36 (2):  50.  doi: 10.16708/j.cnki.1000-758X.2016.0024 Abstract ( 920 )   PDF (5017KB) ( 2091 )   Save Anewevaluationfunctiontocomputeremotesensingimagedefinitionwasproposedaccordingtoengineeringapplicationsandfeaturesofremotesensingimage,toovercometheshortagesoftraditionalimagedefinitionevaluationfunctions.Forlargedataanddifferentscenerydensityanddistributionofremotesensingimages,thedefinitionevaluatingprocesswasseparatedastargetareadetectionandcharacteristicparameterextraction.Firstly,detectionfunctiondetectedwholeimagetogettherichsceneryandobviousedgeareaastargetarea.Thenagraygradientfunctionmadeimagegraypretreatmentandextracteddefinitioncharacteristicparameterstoevaluateimagedefinition.Threedifferentkindsofremotesensingimages,namely,emulateddefocusingimage,emulatednoiseimageandonorbitsatelliteimagewereusedintheproposedmethod,toverifyitseffectivenessandaccuratenessbycomparingitwithfourtraditionalmethods.Theanalysisandemulationresultsshowthattheproposedmethodcanmeetthefourbasicdemandstoevaluatingremotesensingimagedefinitionandtacklethedeficienciesoftraditionalfunctionsinevaluatingdifferentremotesensingimages,itisavailabletoevaluateremotesensingimagedefinition. Related Articles | Metrics

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Thermaldesignandonorbitthermalanalysison YuTu rovermovablecameras ZHANG Bing-Qiang, XIANG Yan-Chao, CHEN Jian-Xin, SONG Xin, MA Ju-Yin 2016, 36 (2):  58.  doi: 10.16708/j.cnki.1000-758X.2016.0001 Abstract ( 805 )   PDF (1849KB) ( 684 )   Save InthebrutaltemperatureenvironmentinSinusIridiumwiththerangebetween-180℃to+90℃,itneedstosolvecameraheatdissipationduringlunardaytimeandheatpreservationinmoonlitnightwithoutelectricenergysupplyunderthecomplexrotationof YuTu Rovermast.Besides，theuncertaintyoflunarduststillresultsinriskstothermaldesign.Inordertosolvetheextremehightemperatureproblemindaytime,themastrotatestoanoptimalpositionforheatdissipationandavoidsthecamerabeingtoohot,andtheproportionofpoweronandoffisoptimized.Inextremelylowtemperatureatnight,thethermalcouplingstateofthecameraandtheroverhasbeenchanged;themastisfoldedintothefencetokeepwarmbymeansofheatpreservationsystems.Basedontheanalysisofthecauseofdustsubsidence,themaxsunelevationangleforworkingisrestrictedtoavoidrisksbydust.Accordingtothethermalanalysisresultsandinorbitresults,itcanbeconfirmedthatthehighesttemperaturedecreased15degreesbymethodsoffindingoptimalpositionandoptimizingtheproportionofpoweronandoff.Byfoldingthemastinmoonnight,camerashavesafelyundergonethecoldnight,therefore45WpowergeneratedbyRHUhasbeensaved.Itindicatesthatthecouplingmethodbetweenthermalcontrolandpostureadjustmentcanbeusedtosolvethehighlowtemperatureproblemofmovablecamerasontheplanet′surfacerover,andreducetheroverpowerdemandforRHU.Itcouldprovidethermaldesignreferenceforthefollowoncelestialbodysurfaceexplorations. Related Articles | Metrics

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Aninstallationdesignofimprovingpointingaccuracyofstarsensorbasedonsemirigidconnection ZHU Hua, ZHANG Chun-Yu, ZHOU Xu-Bin, ZHANG Zong-Hua, GU Zhi-Yue, LYU Kai 2016, 36 (2):  66.  doi: 10.16708/j.cnki.1000-758X.2016.0025 Abstract ( 946 )   PDF (5994KB) ( 1050 )   Save Satelliteperformanceinorbitisimpactedbypointingaccuracyofstarsensorandsyntheticapertureradar(SAR)middleplatebecauseofthermaldeformation.CharacteristicsaboutthermaldeformationofstarsensorandSARwerestudiedandanalysed,andinstallationbetweenSARandsatellitebodywasdesigned.Takingonesatelliteasanexample,SARandsatellitebodywereconnectedwithasemirigid(horizontalconstraintreleased)method,andtheinfluenceofsatellitethermaldeformationwasisolatedtoSARwithacertainrigidity.Asaresult,pointingaccuracyofstarsensorrelativeSARmiddleplateincreased,andmettherequirementofsatelliteimaging.Thisisverifiedbycalculationanalysisandtest,andcanprovidereferenceforotheraerospaceelectroncequipments. Related Articles | Metrics

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Effectofdivergingvariablecrosssectionchannelonperformanceofacuspedfieldthruster CHEN Peng-Bo, LIU Hui, HU Peng, SUN Qiang-Qiang, YU Da-Ren 2016, 36 (2):  74.  doi: 10.16708/j.cnki.1000-758X.2016.0026 Abstract ( 1043 )   PDF (8606KB) ( 426 )   Save Theadaptabilityofcuspedfieldthrusterchangeswithdifferentoperatingconditions,especiallywithdifferentefficiencies,whichchangesalotatdifferentgasflowrates.Toovercomethisproblem,adivergingvariablecrosssectionchannelwasproposedtoimprovetheperformanceofcuspedfieldthrustersatlowandmiddlegasflowrate.Meanwhile,twoconstantsectionchannelswithabigdiameteranda  smalldiameterrespectivelywereintroducedtobecomparedwiththedivergingchannel.Althoughthedivergingchannelmaycausealittledeclineintheatomdensitycomparedtothesmall  constantsectionchannel,thedivergingchannelimprovestheefficiencyatbothlowandmiddlegasflowratesonthepremiseofprovidingaconsiderablethrust,becauseitdecreasestheenergylossofionsatexitandpromotesionizationbyimprovingthemagneticmirrorratio.Incomparison,boththebigconstantsectionchannelandthesmallconstantsectionchannelhavelowperformancesduetoalowerdensityofgasandabiggerwallloss.Therefore,adivergingchannelisbeneficialtoimprovingtheperformanceofacuspedfieldthrusteratlowandmiddlegasflowrate. Related Articles | Metrics

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StudyonEMLandPIMfromconnectiongapinahighpowercoaxialresonator YU Xu-Min, TANG Xiao-Hong, WANG Juan, DAI Feng, LIN Hua-Jie 2016, 36 (2):  81.  doi: 10.16708/j.cnki.1000-758X.2016.0027 Abstract ( 955 )   PDF (1213KB) ( 1118 )   Save Underthevacuumandhighpowercondition,anunstableslightgapofconnectingstructureofacoaxialresonatorwillhaveseveralrisks,includingPIM(PassiveInterModulation)andEML(ElectroMagneticLeakage)problems.Thepercentageofgap′sintegralofsurfacecurrentinthewholeresonatorcavitywasanalyzed.Itshowsthatthegap′slocationisfartherawayfromhighsurfacecurrentstrengthpartofthecavity,thepercentageissmaller.Threekindsofcoaxialresonatorshavebeensimulated.Astableonewaspresentedforreducingthoserisks.Theconnectiongapofthecoaxialresonatorisfarawayfromelectricfieldwavenodesavailable. Related Articles | Metrics