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25 December 2017, Volume 37 Issue 6 Previous Issue    Next Issue

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Momentum envelope analysis and momentum management for spacecraft with a flywheel array LEI Yong-Jun, YUAN Li 2017, 37 (6):  1.  doi: 10.16708/j.cnki.1000-758X.2017.0098 Abstract ( 1177 )   PDF (5760KB) ( 1733 )   Save The problems of momentum envelope analysis and momentum management for spacecraft with a redundant flywheel array were investigated. Firstly,based on analysis of the visualized envelope, a characteristic parameter set was established, and an algorithm was proposed to determine the maximum momenta available from the wheels in a specified direction in threedimensional total momentum space. Furthermore, a momentum management strategy was developed based on a null motion allocation taking the maximum momenta as the reference, to fully utilize the momentum envelope capacity and to avoid the case where wheel momentum saturation appears before the total momentum arriving at the envelope. Finally, comparative numerical simulations were provided to illustrate the effectiveness of the proposed momentum management strategy． Related Articles | Metrics

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Study on the tubenavigation of strictlyregressive orbit YANG Sheng-Qing, DU Yao-Ke, WANG Wen-Yan, WU Jing-Yu 2017, 37 (6):  10.  doi: 10.16708/j.cnki.1000-758X.2017.0097 Abstract ( 1000 )   PDF (5829KB) ( 1081 )   Save The relative motion features between satellite and strictlyregressive reference orbit were investigated to build a tubenavigation method of remotesensing satellite. Since the reference orbit was designed only with the high precision nonspherical perturbation, it had a different dynamic environment with the satellite in space, leading an excursion in alongtrack direction. An alongtrack aligning algorithm was introduced to get rid of the excursion in alongtrack direction based on high precision orbit dynamic model and position sampling method, by which the phasetime excursion and relative motion trajectory were determined. The direct least squares fitting method was introduced to achieve the features of relative motion trajectory. The study on tubenavigation can be applied to autonomous groundtrack keeping of satellites with GNSS measurements. Related Articles | Metrics

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Effect of passive intermodulation on peudonoise code acquisition performance in direct sequence spread spectrum systems SUN Can-Can, TIAN Lu, WANG Yi 2017, 37 (6):  17.  doi: 10.16708/j.cnki.1000-758X.2017.0089 Abstract ( 1055 )   PDF (2763KB) ( 1216 )   Save The satellite communication systems can be jammed by passive intermodulation (PIM) interference signals，and the transmission channel may be blocked at worst. In order to analyze the performance of peudonoise (PN) code acquisition with the passive intermodulation interference quantitatively，the model of direct sequence spread spectrum (DSSS) systems with interference was established. The common methods of PN code acquisition were square law detection and square accumulation detection. The modified Cauchy distribution model was proposed to describe the statistical property of PIM. In consideration of PIM and the receiver noise，the acquisition performances of both detection methods were derived and simulated. The simulation results show that in the case of high signal to interference plus noise ratio(SINR)，the noise has a worse effect on PN acquisition performance than PIM. When the detection probability is 90%，the difference is 2.92dB. The performance of detection method with accumulation is better than that without accumulation，and achieves an accumulation gain. When the detection probability is 90%，the accumulation gain is 2.36dB. Related Articles | Metrics

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Gyrofree spacecraft attitude layered control based on observer ZHANG Ke-Bei, WANG Da-Yi, TANG Liang, WANG You-Yi 2017, 37 (6):  24.  doi: 10.16708/j.cnki.1000-758X.2017.0087 Abstract ( 945 )   PDF (5435KB) ( 1966 )   Save An attitude layered control strategy based on supertwisting observer was presented to address the noncollocated attitude control problem caused by spacecraft payload sensors and base actuators. The dynamics model of spacecraft/Stewart/payload and the equivalent dynamics model in Stewart joint space were built. The supertwisting observer was employed to estimate the spacecraft platform angular velocity. The observer inputs and output are the Stewart strut lengths and relative angular velocity，respectively. The smooth integral sliding mode control law was designed to realize a high precision payload pointing control. The payload attitude information was used by the smooth sliding mode control law. The spacecraft platform controller was designed to achieve a steady spacecraft platform attitude control. The Lyapunov stability analysis shows that the designed controller and observer can guarantee the convergence of the closedloop system. Numerical simulation results illustrate that while gyrosfree in platform，the payload attitude pointing accuracy is up to 0.1″，which is equal to that acquired by platform gyros attitude control. Related Articles | Metrics

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Study on fast back projection algorithm for lunarearth bistatic SAR imaging WANG Guan-Yong, ZHANG Lei, WAN Xin, HU Qing-Rong 2017, 37 (6):  32.  doi: 10.16708/j.cnki.1000-758X.2017.0093 Abstract ( 1624 )   PDF (3666KB) ( 1467 )   Save The concept of lunarbased earth observation concept has been proposed in order to improve the large scale observation ability towards global changes. Because the signal to noise ratio of lunarbased monostatic synthetic aperture radar （SAR） decreases seriously due to the twoway propagation，a novel lunarearth bistatic SAR operating mode was studied. Considering the complex relative movement among lunar，earth and satellite brings difficulty to SAR imaging，a rectangular plane echo model was built according to the geometrical relationship of lunar，earth and satellite. Due to the curves of lunar and satellite orbits，the modeling error was analyzed，and a precise twodimensional frequency domain expression of echo was also deduced. Then a fast back projection based SAR imaging algorithm was designed to compensate the azimuth variant modeling error. The calculation speed was increased by frequency domain subaperture imaging and spectrum combination. The signal noise ratio of lunarearth bistatic SAR is inversely proportional to the distance between earth and lunar through analysis，simulated Xband SAR data sets are used to validate the effectiveness of the proposal to deal with lunarearth bistatic SAR imaging. Related Articles | Metrics

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Optimal faul tdiagnosis algorithm based on reduced order observer TU Yuan-Yuan, WANG Da-Yi, LI Wen-Bo 2017, 37 (6):  40.  doi: 10.16708/j.cnki.1000-758X.2017.0062 Abstract ( 1129 )   PDF (3422KB) ( 1043 )   Save Inordertoreducethecalculationcapacityoffaultdiagnosisalgorithmsandoptimizethealgorithmparameters,anoptimalfaultdiagnosisalgorithmbasedonreducedorderobserverwasproposed.Firstly,areducedorderobserverwasdesignedtoestimatethefaultwithoutcomplexmatrixblockingoperationbydecouplingthestatesofsystemandstatesoffaultbasedontheprincipleoforthogonality.Secondly,theproblemofdeterminingtheobservergainwastranslatedtotheproblemofdesigningoptimalcontrollerforthedualsystemoffaultdiagnosiserrorsystem,basedonwhichtheminimumvarianceestimationoffaultwasimplemented.Thirdly,afaulttolerantcontrollerwasproposedtocompensatethefaultinfluencebyutilizingtheresultofdiagnosis,soastosegregatethesystemwithfaults.Finally,anumericalsimulationwascarriedouttoverifytheeffectivenessoftheproposedmethod.Theresultshowsthatthedesigneddiagnosisalgorithmcanfastconvergetotherealvalueoffaultin7secondsforatwoordersystem. Related Articles | Metrics

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Taskprogrammingmodelsandalgorithmsoftracking and data relay satelliteinapplicationondemand HE Chuan, LI Ya-Jing, QIU Zhen 2017, 37 (6):  46.  doi: 按需申请模式下的中继卫星任务规划模型与算法设计 10.16708/j.cnki.1000-758X.2017.0064 Abstract ( 827 )   PDF (1992KB) ( 1128 )   Save ThetasksplanningmethodofTDRSinapplicationondemandmodelwasstudied.Thecommondescriptivecharacteristicsoftaskweresummarizedanddividedintobasicandadditionalcharacteristics.Theplanningprocessandthestatechangeprocessoftaskinasynchronousresourceavailperiodwasanalyzed.Theclassificationmethodoftasktypeandtheconstructedmethodoftasksetswasproposed.Themainconstraintconditionsoftaskplanningweregiven,andtheoptimalobjectsfromapplicantandmanagerswereproposed.Ataskplanningalgorithmwasdesignedbasedontheriskaversionrule,aftertheconflictdetectionmodelandopportunityevaluationmodelwereconstructed. Related Articles | Metrics

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Application of wavelet analysis in GPS satellite fault detection HE Li-Wen, LI Xin-Guo 2017, 37 (6):  56.  doi: 10.16708/j.cnki.1000-758X.2017.0084 Abstract ( 931 )   PDF (1373KB) ( 1220 )   Save At present, the residual chisquare detection method based on extended Kalman filter has been widely used in GPS satellite fault detection independently by the receiver. However, this method has some problems such as dependency on mathematical model and detection delay. A GPS satellite fault detection method based on wavelet analysis was proposed. The wavelet analysis was used to analyze the GPS data in the time and frequency domain, and the data could be processed as multiscale analysis. Abnormal points were used to determine the occurrence of failure. The simulation results show that the proposed method is efficient, sensitive, concise and easy to implement. It′s useful to the reliability and stability of navigation system. Related Articles | Metrics

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Effect of diamond on sputtering resistance performance of Hall thruster channel wall LI Qing-Man, WANG Ping-Yang, XU Zong-Qi 2017, 37 (6):  62.  doi: 10.16708/j.cnki.1000-758X.2017.0071 Abstract ( 882 )   PDF (5480KB) ( 972 )   Save In order to lengthen the lifetime of Hall thruster，the BN ceramic channel wall was changed to diamond wall，which can improve the sputtering resistance of thruster.The diamond’s influence on magnetic field and secondary electron emission was considered to analyse the practicability. In addition，the BN ceramic test pieces with diamond film were under ion sputtering experiment by weight method. The relationship between the sputtering yield and the ion incident angle was obtained by semiempirical formulation method，and was used in particle movement simulation program to forecast the shape change of diamond channel wall to obtain the corrosion rate. The experiment results show that the sputtering yield of diamond is relative decreased by 75% compared to the BN ceramic in different incident angles. The simulation results show that the diamond is good at improving the corrosion situation of channel wall,and 0.7mm thickness diamond film can resist the ion sputtering for 5000~6000h，so it is helpful to improve the lifetime of Hall thruster. Related Articles | Metrics

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Designandapplicationofheatpipethermalswitchonlunarbasedultraviolettelescope ZHANG Bing-Qiang, 吕Wei , ZHANG You-Wei, LI Fu, LIU Zi-Jun, GUO Lin, MIAO Jian-Yin 2017, 37 (6):  68.  doi: 10.16708/j.cnki.1000-758X.2017.0049 Abstract ( 1044 )   PDF (8384KB) ( 752 )   Save Inthebrutaltemperatureenvironmentinmoonsurfacewiththerangeof-180℃to90℃,itneedstosolvetheLunarBasedUltravioletTelescope（LUT）heatdissipationduringlunardaytimeandheatpreservationduringmoonlitnightwithoutelectricenergysupply.Inordertosolvetheheatconsumptiontransmission,discharge,andtheheatpreservationproblemofmoonnight,apassiveheatpipethermalswitch（HPTS）wasproposedasameansoflongdistanceheattransferbetweenthedeviceandtheradiator,accordingtothephasetransitioncharacteristicsoftheworkingfluid.Dependingontheequipmenttemperatureindex,aworkingfluidwithsuitablefreezingpointandheattransfercapacitywasselected.TheHPTSwasfilledwithworkingfluid,whichcantransmitenergyfromevaporatortocondenserbyphasechange.Inextremelylowtemperatureofthenight,theworkingfluidisfrozen,itcausestheconnectiontobeinterrupted,andthentheLUTcanbemaintainedabovethesurvivaltemperature.IthasbeenproventhroughthegroundtestandinorbitresultthattheswitchingratioofHPTSisgreaterthan30nearthefreezingpoint.Ataworkingtemperatureof7℃,theheattransfercapacityofHPTSisgreaterthan15W,andheattransfertemperaturedifferenceislessthan4℃.Inaddition,theHPTScanaccommodateLander′stiltof±15°.AllthepropertiesoftheHPTSensurethattheLUTonLanderworksinorbitwithhighperformance. Related Articles | Metrics

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Influenceanalysisoflithiumionbatteryconfigurationoutside〖JP〗theeast/westpanelonGEOsatelliteplatform LIU Bai-Lin, LI Xiu-Feng, ZHOU Zuo-Xin 2017, 37 (6):  75.  doi: 10.16708/j.cnki.1000-758X.2017.0043 Abstract ( 1551 )   PDF (4471KB) ( 1178 )   Save TooptimizetheequipmentconfigurationschemeofGEOsatelliteplatform，aLithiumionbatteryconfigurationoutsidetheeast/westpanelwasproposed.Thefeasibilityoftheschemeanditsinfluenceonsatelliteplatformwereanalyzedfromseveralaspects，especiallyinstructuraldesign，thermaldesignaswellasdevelopmentprocessofsatelliteplatform.Takingthe135A·hLithiumionbatteryasanexample，theanalysisresultsofthermalcontroldesignshowthatthenewconfigurationofLithiumionbatteryhasmoreadvantagescomparedtoitsconfigurationinsidethesouth/northpanel.Thenewconfigurationnotonlysavesmorelayoutspaceforlotsofequipmentinsidethemoduleofsatelliteplatform,butalsooptimizesthedevelopmentprocessofthesatellite.Furthermore，themechanicalandthermalperformancesofthemountingpanelarealsoimproved.Forinstance，theheatingpowerandheatrejectionareaaredecreasedby70%.Significantsavingsofthedesignresourcesareobtained.Therefore，theproposedconfigurationisaneffectiveapproachtoenhancethesystemperformanceofsatelliteplatform. Related Articles | Metrics

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PreliminaryperformanceanalysisofthefirstbackupsatelliteofBeiDouNavigationSatelliteSystem LIU Xiao, ZHAO He, ZHAO Long 2017, 37 (6):  82.  doi: 10.16708/j.cnki.1000-758X.2017.0060 Abstract ( 934 )   PDF (4617KB) ( 1036 )   Save TofurtherenhancethecapabilityofBeiDouNavigationSatelliteSystem(BDS)to providecontinuousandefficientservice,thefirstbackupsatelliteI6waslaunchedinMarch2016.ThedifferencesandsimilaritiesbetweenI6andotherIGSOsatelliteswereanalyzed,fromtheperspectiveofsatelliteclockprediction,orbitdeterminationaccuracyandpseudorangevariation.ThecontributionofI6toBDSwasevaluatedbyPDOPvaluesandgridavailability.Thesatelliteclockmeasurementsobtainedbytwowaysatellitetimefrequencytransfer(TWSTFT)systemwereusedtoevaluateclockpredictionerrorofI6.Theresultsshowthatfor5hourprediction,clockerrorofI6is232nsintermsofrootmeansquare(RMS)andtheextrapolatedonehourpredictionerroris073ns(RMS).ComparedwithotherIGSOsatellitesclock,theerrorforecastlevelofI6isequivalent.TheorbitdeterminationaccuracyofI6optimizedbytheattitudecontrolmethodisnotdegradedobviouslycomparedwiththeI3ofBDSwhentheSunisclosetotheI6′sorbitplane,whichovercomesthedecreaseoftheorbitaccuracyoftheexistingBDSsatellitesduringtheshadow.ThepseudorangevariationoftheI6satellitewasanalyzedusingthedatacollectedbythelargeapertureparabolicantenna.Theresultsshowthatthepeaktopeakdifferenceofthepseudorangevariationisabout1minthesingleobservationarcofI6satellite.ItisconsistentwithotherIGSOsatellites.I6isinthehotstandbymodeofoperation,providingserviceswiththeoriginalBeiDousatellitesafterMay2016,changingtheBDSconstellationcomposition.TheresultsofPDOPsimulationshowthatthemaximumPDOPofKaShiisdecreasedfrom1282to726,andthepercentageofPDOPgreaterthan6isdecreasedfrom2911%to1721%.TheresultsshowthatI6increasestheavailabilityofsixionosphericgridpoints. Related Articles | Metrics

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Methods of spacecraft impulsive relative hovering and trajectory safety analysis CHENG , YUAN Jianping, QIAN Yingjing, MA Weihua 2017, 37 (6):  89.  doi: 10.16708/j.cnki.1000-758X.2017.0096 Abstract ( 1449 )   PDF (1170KB) ( 991 )   Save Based on the analytical solutions of TH equations and its state transition matrix form, the openloop control method of spacecraft impulsive relative hovering was studied, which is promising for practical engineering use. The true anomaly intervals of the hovering impulse were optimized by the nonlinear mathematical programming. Based on the calculation of collision probability, the method of safety analysis and risk management was proposed. The numerical simulations show that the introduced relative hovering method can be used for circular and elliptical reference orbits hovering. Furthermore,the local optimal solution can be obtained by applying the true anomaly intervals optimization method. The maximum collision probability and the minimum relative distance nearly appear at the same time. And, the smaller the relative distance is, the larger the collision probability. Related Articles | Metrics