中低轨道卫星通信的频率特点

1中低轨道卫星通信的频率特点解放军理工大学通信工程学院李广侠2一、中低轨卫星通信系统的现状二、中低轨卫星通信特点和频率三、发展我国星座卫星通信及启动频率论证报告内容3第一部分中低轨道卫星通信的现状“铱”系统-典型的中低轨卫星通信系统5铱星网络结构图工作频率波段:业务链路:L波段1616-1626.5MHz星际链路:Ka波段23.18-23.38GHz地面段链路:上行:Ka波段;19.4-19.6GHz下行:Ka波段;29.1-29.3GHz•业务种类：话音、传真、寻呼、数据空间段：星数：66＋6轨道数：6个轨道高度：780公里运行周期：100分钟28秒点波束数量：48个/卫星铱星概述7▲1987年由摩托罗拉公司提出▲1997年5月5日铱系统公司首次将5颗铱卫星发射上天▲到1998年5月17日共发射了67颗卫星，完成了由66颗卫星组成的卫星星座▲1998年11月1日正式开始提供话音业务，11月16日开始提供寻呼业务▲2000年3月27日铱系统正式结束业务▲现由新铱星公司接管，为美国国防部提供话音和数据通信业务，2002年还补发了5颗铱星。铱系统的简历8IridiumSatelliteLLCOverview•SystemacquiredDec2000•Committed,multinationalinvestorgroupfromSaudiArabia,Brazil,Australia,andUSA•Commercialservicere-introducedMarch2001withmaintainablecoststructure•StrategicrelationshipwithBoeingforsatelliteconstellationoperationsandmaintenance•2014constellationlifespan•Significantlyreducedpriceandsimplifiedpricingplan•Verticalmarketdistributionstrategyforvoiceanddataservices•TheU.S.Governmentisananchorcustomer.Activelypenetratingglobalmarket9EntireNetworkinSpace•66satellitesoperatein6polarorbitalplanes780kmabovetheearth•Eachsatellitefootprintapproximately5000kmindiameter•Allsatellitefootprintsoverlap•Eachsatellitehas48spotbeams•Eachspotbeamfootprintapproximately450kmindiameter•Allspotbeamsoverlap•Switchinthesky–onboardprocessingandswitchingforefficiency,flexibility,andquality•Inter-satellitelinkenablestheentirenetworkinthesky–coverseveryinchontheearthandimmunefromterrestrialdisaster•13inorbitalsparesatellitesTheonlyoperatorcapableofprovidingtrulyglobalvoiceanddataservice10SatelliteConstellationUbiquitousCoverage•theonlysystemwithtrueglobalavailabilitySeamlessOperations•theonlysystemwithcontinuousvisibilityofmultiplesatellitesforhighreliabilityConstellationCapacity•processandcontrol72,000simultaneousphonecalls•support2MactivecustomersMaturedImplementation•completelyde-buggedsystemFinancialStability•Debtfreeandbreak-eveninoperations11SatelliteTechnologyComparisonTraditionalSatelliteSystems-Inmarsat,Thuraya,Aces,Globalstar,etc.–Architecture•Bentpipe–Coverage•Regional•CallersandearthstationsmustbeundersamesatelliteIridium-EntireTelecommunicationsNetworkinSpace–Architecture•Onboardprocessingandswitching•Crosslinkbetweensatellites–Coverage•TrulyGlobal•Callerscanbeanywhereintheworld12AdvancedIridiumSystemArchitectureOnboardproessing/switchingandInter-satellitelinkstoprovide-Pole-to-Polecoverage-GatewaynotrequiredwithinsatellitefootprintIridiumCallTopology&PerformanceAccessRequest,VoiceTraffic,SignalingIRIDIUMConstellationTempeorBeijingGatewayAustraliaOriginatingMobileUserVoiceTraffic,SignalingSignalingSouthChinaSeaDestinationMobileUser•VoiceandDataServices–TempeGWmeasuredperformance:8,590weeklytestcalls•99.2%Callsuccessrate•0.6%Calldroprate•ShortBurstDataServices–TempeGWmeasuredperformance•99.64%Firstattemptmessagesuccessrate14IridiumTrafficDistribution15PersonalDataConnectivityMModemRARateAdapterMobileSwitchingCenterMInternetServiceProviderMPSTNInternetIridiumGatewayDial-UpConnectivityDirectInternetConnectivityMobileSwitchingCenterInternetIridiumGatewayRADirectInternetServerRA•Fasterconnectiontime–10secondsascomparedto40secondsfordial-upPPP•Transparentcompressionforimprovedthroughput•SmartConnect–seamlessconnect/disconnect–Reduceson-aircharges–MaximizesISUbatterylife–Reconnectsautomaticallyifconnectiondropped•Notail-endchargesincurredatGateway16EnterpriseDataServices•RUDICS-RouterbasedUnstructuredDigitalInterworkingConnectivitySolution•KeyBenefits:–Gatewayrovidesvirtualmodemportsthatcanberoutedviaterrestrialdataconnections–Significantlyreducedconnectiontimesandincreasedthroughputusingindustrystandard(PPP)compression(see10Kbpsperchannel)–Abilitytogangchannelstogetherforhighbandwidthapplications(3channelsnominalthroughputequivalenttoSWIFT64LeasedLineORVPNORInternetIridiumGatewayD900RUDICSServerRemoteApplicationApplicationHostServerEndUserAccess17IridiumGatewayD900SBMNetworkEquipmentInternetUserApplicationShortBurstData•An“ultra-efficient”waytotransmitrelativelysmallamountsofdataacrosstheIridiumNetwork–70bytesinaboutasecondafterchannelacquisition(typicaltotaltimeof5secondsfora110CharacterMessage)–Mobile-originated,two-wayexchangeswithflexiblerangeofshortmessages(approximately2,000bytes)•IdealforAssetTracking,Monitor,andControlApplications–Telemetryandtelecommond–Positionreporting–Weatherrequests–Datacollection–Safetyalert–SOS–etc.18WirelessPhoneorDataDeviceIridiumHandsetwithWirelessBaseStationIridiumGatewayRemoteWirelessLocalLoopInternetPSTNRUDICSSBMServer19AsymmetricBroadBandDataBroadcastSatellite(GEO)Iridium(LEO)IridiumGateway/ISPSerialNICSatelliteISPAuthenticationCenter&ContentServerBroadbandSatelliteTransmissionFacilityBroadbandSatelliteSubscriber20前期失败的原因：◆定位不准，无法与地面蜂窝系统竟争；◆技术复杂，研制周期过长；◆通信价格过高；◆资本运作失败。复活的原因：◆真正的全球通信；◆小终端低时延的移动通信；◆高效的运营方式。铱系统失败和成功的启示工作频率波段:业务链路:L波段1616-1626.5MHz馈线链路:上行:C波段/6875-7055MHz下行:C波段/5091-5250MHz•业务种类：话音，传真、数据、定位空间段：星数：48＋8轨道数：8个轨道高度：1414公里运行周期：114分钟点波束数量：16个/卫星全球星(Globalstar)概述22全球星系统网络结构23全球星系统特点•尊重各国、各地区通信主权：所有呼叫，包括国际呼叫，都将经关口站接入业务提供商现有地面公网和移动网络—扩大各地区业务提供商的运营范围和业务收入—通信管理当局可以按需要实行