Chinese Space Science and Technology ›› 2017, Vol. 37 ›› Issue (1): 75-81.doi: 10.16708/j.cnki.1000-758X.2017.0014

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DecodinganalysisoftimeinformationfromspacebasedAISmessage

 LI  Shi-You, CHEN  Li-Hu*, CHEN  Xiao-Qian   

  1. CollegeofAerospaceScienceandEngineering,NationalUniversityofDefenseTechnology,Changsha410073,China
  • Received:2016-06-07 Revised:2016-07-12 Published:2017-02-25 Online:2017-01-24

Abstract: Thetimeinformationevaluatedfromthemessageoftheautomaticidentifyingsystem(AIS)isofmostimportanceinmonitoringandcontrollingoftheglobalvessels.Aimingatcontinuouslymonitoringsomeparticularvessels,thetimeinformationintheAISmessagesoftheAISsystemsonboardboththeTianTuo-1(TT1)andTianTuo-3(TT3)micro-nano-satelliteswasstudied.Firstly,astatisticalanalysiswasperformedbyemployingtheAISdatareceivedbytheTianTuo-1nano-satelliteduringitsonorbitoperation.TheresultssuggestthatitisimpossibletoobtainthetimeinformationmerelybytheAISmessageitself.Secondly,thecompositionandformatoftheAISmessagereceivedbytheTT3-AISwasstudied.IntheTT3-AISsystem,atimeflagwasgeneratedeveryminutetobeinsertedintothereceivedAISdatapackage.ThustheTT3-AIShasagoodfunctiononaddingthetimeinformationtotheAISmessages,whichwillbehelpfulformonitoringandcontrollingoftheglobalvessels.

Key words: TianTuo-1nano-satellite, TianTuo-3micro-nano-satellite, space-basedAIS, SOTDMA, time-flag