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115个结果
  • 简介:把引力与惯性分开的问题在很一般的感觉被讨论,并且结论是积极的:人能把引力与惯性分开,如果各种各样的观察技术被申请。在卫星gravimetry的加速表鈥檚位置问题被调查,并且由于在团之间的一台仪器以及差别的位置错误,中心和重力集中的另外的加速效果被探索。

  • 标签:卫星重力测量分离问题质心重心引力惯性力
  • 简介:RPC模型最近在摄影测量学和遥感社区提起了可观的兴趣。RPC是能够完成高近似精确性的一个概括传感器模型。不幸地,RPC模型的参数的计算服从于在所有可得到的文学的参数起始。为没有起始的价值的RPC模型的参数的计算的一个算法在SPOT-5上被介绍并且测试,CBERS-2,ERS-1imageries。RPC模型对推扫帚和SAR形象合适。

  • 标签:RPC模型卫星图像遥感技术非线性
  • 简介:挑战性的微型卫星收费载重的精确轨道决心(捣烂)卫星基于位置和在武汉大学里被开发的航行数据分析家(熊猫)软件被做,用从白天126~131的年2002的机载的GPS数据。Theorbit精确性被从GFZprocessed以后科学轨道(PSO)分析差别估计,GPS搬运人和伪范围数据剩余和变化的卫星激光(SLR)剩余。

  • 标签:GPS全球定位系统卫星跟踪精密度
  • 简介:ThispaperhasanalyzedtheperturbationsofaGeoX-Sat(virtualsatellite)ingeostationaryorbit(GEO).Andcontrolmethods,strategiesandcalculationprocessesaredesignedoftheEast-West(E/W)station-keepingoftheGeoX-Sat.TheAttitudeandOrbitControlSubsystem(AOCS)providesattitudeinformationandmaintainstherequiredspacecraftattitudeduringallphasesofthemission,startingatspacecraftseparationfromthelaunchvehicleandthroughoutitsoperationallifetime.FortheGeoX-Satexercisingdesign,duetotimelimitations;onlytwomodesofoperationwereconsideredafterassumedlaunchingoperation:normalandstationkeeping.

  • 标签:
  • 简介:Onthebasisofconsideringdownlinkpowerfluxdensitylimit,shadowingeffectfrequencyreuseindifferentsystemsandadjoiningbeamsofsamesystem,adoptingvoiceactivityandpolarizationisolationtechniques,thecapacityofCDMAmobilesatellitecommunicationsystematdifferentdownlinkpowerfluxdensitylimitmodes,channelspreadbandwidthandmobileuser’squalityfactorofreceivingsystem(G/T)areanalysedandcalculated,andcomparedwiththeonesofTDMAandFDMA.Theconclusionsaregivenattheendofthispaper.

  • 标签:CDMASystemcapacityINTERFERENCESATELLITECOMMUNICATION
  • 简介:AnewSuboptimalMaximumLikelihoodEstimation(SMLE)algorithmbasedonfull-derampmodelanditsimplementationinsatellite-borneradaraltimeterarepresented,withemphasisontheinfluenceofboththereturnfluctuationandthereceivernoiseonheightandslopeestimationprecision.Someconclusionsareobtainedandverifiedbycomputersimulation.

  • 标签:Satellite-borneRADARALTIMETERSignalprocessingSMLE
  • 简介:一个新估计方法被建议,它利用unscentedtransform方法,因此,真平均数和协变性更精确地被接近。没有为EKF必要的linearization进程,新方法能被用于非线性的系统,并且它不要求噪音的Gaussian分布并且什么“s更多的,它实现和更精确的评价特征的容易使它能在卫星轨道模拟的实验表明它的好性能。数字实验证明unscentedKalman过滤器的申请比EKF更有效。

  • 标签:轨道模拟卡尔曼滤波器卫星大地测量非线性系统
  • 简介:Inthisresearch,acontent-basedimageretrieval(CBIR)systemforhighresolutionsatelliteimageshasbeendevelopedbyusingtexturefeatures.Theproposedapproachusesthelocalbinarypattern(LBP)texturefeatureandablockbasedscheme.Thequeryanddatabaseimagesaredividedintoequallysizedblocks,fromwhichLBPhistogramsareextracted.TheblockhistogramsarethencomparedbyusingtheChi-squaredistance.ExperimentalresultsshowthattheLBPrepresentationprovidesapowerfultoolforhighresolutionsatelliteimages(HRSI)retrieval.

  • 标签:基于内容的图像检索高分辨率卫星影像纹理特征CBIR开发利用二元模式
  • 简介:Toestablishanefficientinter-satellitelink(ISL)inanLEOnetwork,theeffectofgeometriccharacteristicsofISLontheISLsandthedevicesontheLEOsatelliteshouldbeexamined.BecauseofthecontinuousmovementoftheLEOsatellite,thetime-varyingbehavioursoftheISL'sgeometriccharactersisticscontinuouslychangewiththechangesofthesatellite'spositionontheorbit.ThesedynamicgeometriccharacteristicsoftheISLsareimportantforISL'sperformanceanalyzingandthedesignofthedevicesontheLEOsatellite.ThispaperdescribesdynamicgeometriccharacteristicsofISL,analyzestheimpactoftheseregulationsonthetrackingsystemofthesatellite'santennaandthepoweradjustingsystemofthesatellite'stransmitter,withtheIridiumsystemasanexample.

  • 标签:星间互联低地轨道卫星通信动态特性
  • 简介:SVLBI(空间很长的基线干涉量度)在测地学和地球动力学有一些重要潜在的应用,为哪个最困难的任务是精确决定一颗SVLBI卫星的轨道。这个工作学习将可能能决定一颗空间VLBI卫星的轨道的几种技术。然后,根据为测地学的学习和GNSS的几何学的卫星和要求的类型和特征(GPS,伽利略)追踪空间VLBI卫星的卫星,SVLBI卫星(TEST-SVLBI)的六个Keplerian元素被决定。一个程序被设计由网络,追踪的网络ofTEST-SVLBI与被设计的车站分析不同高度的空格的范围区域。由网络追踪TEST-SVLBI的效率被学习,并且结果被介绍。

  • 标签:SVLBI大地测量卫星轨道跟踪网设计
  • 简介:Theexploitationofdifferentnon-rigorousmathematicalmodelsasopposedtothesatelliterigorousmodelsisdiscussedforgeometriccorrectionsandtopographic/thematicmapsproductionofhigh-resolutionsatelliteimagery(HRSI).Furthermore,thispaperfocusesontheeffectsofthenumberofGCPsandtheterrainelevationdifferencewithintheareacoveredbytheimagesontheobtainedgroundpointsaccuracy.Fromtheresearch,itisobviouslyfoundthatnon-rigorousorientationandtriangulationmodelscanbeusedsuccessfullyinmostcasesfor2Drectificationand3Dgroundpointsdeterminationwithoutacameramodelorthesatelliteephemerisdata.Inaddition,theaccuracyuptothesub-pixellevelinplaneandaboutonepixelinelevationcanbeachievedwithamodestnumberofGCPs.

  • 标签:图象处理摄影测量人造卫星三角测量
  • 简介:这份报纸为用BDS(BeiDou航行卫星系统)估计湿折射度地的精确论述一条新奇途径模拟仅仅,为深圳和香港GNSS的GPS,和BDS+GPS联网。模拟被把人工的噪音加到真实观察数据集执行。,而不是使用,从观点计算的d和s参数在以前的研究弄湿延期,我们采用偏爱和RMS参数,从全部的voxels的断层摄影术结果计算了,回答决心以便获得折射度的精确的更直接、全面的评估。结果显示出那:(1)湿折射度估计了独自使用BDS的tropospheric(仅仅使用的9颗卫星)的精确基本上比得上GPS的;(2)BDS+GPS(当前的操作)不能显著地改进数据为折射度断层摄影术的应用程序的空间密度;并且(3)特别地在更低的空气,折射度断层摄影术的精确的任何细微增加在中国运作的气象学的服务上为任何应用依赖者忍受大意义。

  • 标签:北斗导航卫星系统折射率场层析成像对流层模拟精度全球定位系统
  • 简介:Satellitecells(SCs)hasbeenshowntobethesourceofmyogenicprecursorcellsresponsibleformusclefiberrepairandregenerationduringatrophy,afterinjuryorneuromusculardisorders.RecentstudiesdemonstratedthefeasibilityofautologousSCstransplantationforrepairofmyocardialnecrosis.

  • 标签:
  • 简介:Satelliteconstellationdesignforspaceopticalsystemsisessentiallyamultiple-objectiveoptimizationproblem.Inthiswork,totacklethischallenge,wefirstcategorizetheperformancemetricsofthespaceopticalsystembytakingintoaccountthesystemtasks(i.e.,targetdetectionandtracking).Wethenproposeanewnon-dominatedsortinggeneticalgorithm(NSGA)tomaximizethesystemsurveillanceperformance.Paretooptimalsetsareemployedtodealwiththeconflictsduetothepresenceofmultiplecostfunctions.Simulationresultsverifythevalidityandtheimprovedperformanceoftheproposedtechniqueoverbenchmarkmethods.

  • 标签:空间光学系统性能指标星座设计卫星非支配排序遗传算法多目标优化问题
  • 简介:温室气体甲烷的空间与时间的可变性(在在亚马逊上的空气的CH4)从卫星转菠的大小用数据被学习大气红外线在为时期2003-12的NASA水卫星上更健全。结果在亚马逊盆低地区域上显示出这气体的显著可变性,在沼泽地区域发生的地方。CH4有明确的季节的行为,随它在旱季期间的集中的进步增加,在湿季节期间由减少列在后面。有关这可变性,现在的学习在modulating显示ENSO的重要角色在北亚马逊上的CH4排出物的可变性,这个协会在哪儿似乎主要响应ENSO相关的降水在充满的区域被连接到变化,变化。在这个区域,CH4减少(增加)由于ElNi?o相关(LaNi?一相关)干(湿)。在另一方面,在东南的亚马逊上烧在期间的生物资源的增加(减少)很干燥(湿)年在这个区域在CH4排出物解释增加(减少)。现在的分析识别亚马逊的二个主要区域,它的北、东南的部门,与CH4的显著interannual变化。这结果可能为未来在CH4,的集中监视变化是有用的秒大多数重要温室气体,在这个区域。

  • 标签:甲烷排放量时空变化卫星观测亚马逊温室气体ENSO
  • 简介:Accordingtothepreciseephemerishasonlyprovidedsatellitepositionthatisdiscretenotanytime,soproposethatmakeuseofinterpolationmethodtocalculatesatellitepositionatanytime.TheessaytakeadvantageofIGSpreciseephemerisdatatocalculatesatellitepositionatsometimebyusingLagrangeinterpolation,Newtoninterpolation,Hermiteinterpolation,Cubicsplineinterpolationmethod,Chebyshevfittingmethodrespectively,whichhasadeeplyanalysisintheprecisionoffiveinterpolations.TheresultsshowthattheprecisionofCubicsplineinterpolationmethodistheworst,theprecisionofChebyshevfittingisbetterthanHermiteinterpolationmethod.LagrangeinterpolationandNewtoninterpolationarebetterthanothermethodsinprecision.Newtoninterpolationmethodhastheadvantagesofhighspeedandhighprecision.Therefore,Newtoninterpolationmethodhasacertainscientificsignificanceandpracticalvaluetogetthepositionofthesatellitequicklyandaccurately.

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  • 简介:Currently,1bitor2bitsignalquantizationiswidelyusedinsatellitenavigationsoftwarereceivers.Thebit-wiseparallelalgorithmhasbeenproposedfor1bitand2bitsignalquantization,whichperformscorrelationwithhighefficiency.Inordertoimprovetheperformanceofthecorrelator,thispaperproposesanew1.5bitquantizationmethod.Theoreticalanalysesaremadefromtheaspectsofcomplexityandquantizationloss,andperformancecomparisonbetween1.5bitquantizationcorrelatorandtraditionalcorrelatorsisdiscussed.Theresultsshowthatthe1.5bitquantizationalgorithmcansaveabout30percentcomplexityundersimilarquantizationloss,reducemorethan0.5dBsignalnoiseratio(SNR)lossundersimilarcomplexity.Itshowsgreatperformanceimprovementforcorrelatorsofsatellitenavigationsoftwarereceivers.

  • 标签:软件接收机信号量化卫星导航相关器设计性能比较
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