Handbook of Satellite Applications PDF
Preview Handbook of Satellite Applications
US Domestic Communications Satellite Systems Joseph N. Pelton Nameofsystem Websitefor (andHQ latest location) Operator Typeofservice information DBSD(Bellevue, FormerICOGlobal Hybridterrestrial- www. Washingtonand CommunicationsSubsidiary satellitelandmobile DirecTV.com/ Reston,VA, (onesatelliteplusterrestrial service USA) mobile)(nowownedby DirecTV) DirecTV DirecTV Broadcastsatellite www.directv. service-DBS com Dish Dish(Echostar) Broadcastsatellite www.echostar. service-DBS com www.dish.com Galaxyand Intelsat FixedandDTH www.Intelsat. IntelsatAmericas service com Sats GESat GeneralElectric Fixedsatelliteand www.gesat. DTHservice com GStar GTE&SESAmericom Fixedsatelliteand www.geo- DTHservice orbit.org/ westhemipgs/ fgstar4p.html HughesNet HughesNetworkSystems IP-basedbroadband www.hns.com dataservices.Now providedbyJupiter Satellites (continued) J.N.Pelton(*) InternationalSpaceUniversity,Arlington,VA,USA e-mail:[email protected] #SpringerScience+BusinessMediaNewYork2015 1 J.N.Peltonetal.(eds.),HandbookofSatelliteApplications, DOI10.1007/978-1-4614-6423-5_1-2 2 J.N.Pelton Nameofsystem Websitefor (andHQ latest location) Operator Typeofservice information JSAT(Horizon) JapanSatellite DTHandFSSservices www.jsati. com/news. asp? DocID=180 LightSquared LightSquaredNetwork Hybridmobilesatellite www. (formerlyMobile andterrestrialcellular lightsquared. Satellite service com/ Ventures) SESAmericom SESGlobal DTHsatelliteandfixed www.ses- satelliteservice americom.com Sirius(Nowpart XMRadioInc. Directbroadcastradio www.xmradio. ofXMRadio) com/ bestofsirius/ index.xmc Terrestar TerreStarCorporation(now Hybridmobilesatellite www. ownedbyDirecTV) andterrestrialcellular DirecTV.com/ service Viasat Viasat-1andViasat-2tobe Broadbandservice deployedshortly WildBlue WildBlueCommunications Fixedsatelliteand www. (FormerlyKa Inc. DTHservice wildblue.com star) XMRadio XMRadioInc. Directbroadcastradio www.xmradio. com TablepreparedandcopyrightedbyJosephN.Pelton,printedbyhispermission Satellite Communications Overview Joseph N. Pelton Contents Introduction......................................................................................... 2 OverviewofCommercialSatelliteServices....................................................... 3 Conclusion.......................................................................................... 9 References.......................................................................................... 9 Abstract Inthe50yearsthatfollowedthefirstsatellitelaunchesofthelate1950sandearly 1960s, the diversity of satellite services has expanded enormously. Today, there aredirectbroadcastradioandtelevisionservicestothehomeandeventomobile receivers. Thereare mobile satelliteservicesto airplanes, ships atsea, and even hand-heldtransceivers.Thereareso-calledfixedsatelliteservicestoearthstations of various sizes down to so-called very small antenna terminals (VSATs), microterminals, and even ultra small aperture terminals that can be located on desktops.Therearedatarelaysatellitesandbusinesstobusinesssatellitesystems. The age of the Internet and data networking has certainly served to add to the diversity of satellite services. Technology innovation has also led to the growth and development of satellite communications services. Lower cost launch arrangementsanddevelopmentofearthstationtechnologyandparticularlyappli- cationspecificintegratedcircuitshavebeenkeytodrivingdownthecostandsize ofground antennasand transceivers.The development of three axis body stabi- lized spacecraft, better solar cells and batteries, and more effective on-board antenna systems and on-board switching among multi-beam antennas have also furthered the cause. Finally, the development of not only bigger and better satellites but the evolution of satellite systems design and network architecture J.N.Pelton(*) FormerDeanandFaculty,InternationalSpaceUniversity,Arlington,VA,USA e-mail:[email protected] #SpringerScience+BusinessMediaNewYork2015 1 J.N.Peltonetal.(eds.),HandbookofSatelliteApplications, DOI10.1007/978-1-4614-6423-5_2-2 2 J.N.Pelton that allowed networks to be deployed in different types of orbits and network constellationshasbeenpartofthison-goingevolution. The latest iterations of satellite design have led to almost opposite extremes. On one hand there are large, sophisticated multi-ton satellites, known as high throughputsatellites,deployedintraditionalgeosynchronousorbitlocations.On theotherhand,therearealsosmallbutcapablesatellitesinlowtomediumearth orbit constellations. These new satellite networks are being designed with more andmoremass-producedsatellites–uptoathousandormoreinasinglesystem– toincreasenetworkcapacitybymeansofdeployingmoreandmoresatellitesin lowerorbit. This chapter provides a general introduction to all of these changes and an overview to the entire field. Changes to satellite communication networks over the past half century have come not only in services and technology butalso in regulation, standards, frequency allocations, economics, as well as the global reachandimpactofsatellitesontheentirescopeofhumansociety. Keywords Broadcast satellite service (BSS) (cid:129) Data relay satellites (cid:129) Fixed satellite service (FSS) (cid:129) Geosynchronous earth orbit (GEO) (cid:129) International Telecommunication Union(ITU)(cid:129)Intersatellitelink(ISL)(cid:129)Lowearthorbit(LEO)(cid:129)Mobilesatellite service(MSS)(cid:129)Satelliteconstellations(cid:129)Storeandforwardsatelliteservice Introduction The serious consideration of the provision of satellite communications from space dates from 1945 when the first technical descriptions were written with regard to launchingaspacecraftintogeosynchronousorbitandthedesignofspacestationsas extraterrestrial radio relays was specifically outlined. In the historical section that follows, however, it becomes clear that the idea or concept had been around many years, indeed centuries before. The 1945 article, however, described the possible deliveryoftelecommunicationsservicesfromspaceandpresenteddetailedcalcula- tions as to how this might efficiently be done from a special orbit known as the geosynchronous (or sometimes the geostationary) orbit (Clarke 1945). Today, this orbitisevensometimescalledtheClarkeorbit. The new capability that allowed satellites to be launched that came from tech- nology development in the USSR and the USA in the late 1950s and early 1960s expanded into the capability to launch a satellite into geosynchronous orbit – that camein1963–allowedtherapidevolutionofsatellitecommunicationstechnology. Within a decade, a wide variety of telecommunications services from satellites in different types of orbits became possible. The International Telecommunication Union(ITU),thespecializedagencyoftheUnitedNationsthatoverseestheuseof radio frequencies (RF) for practical and scientific purposes assumed responsibility for satellite radio frequencies. This began with a globally attended Extraordinary SatelliteCommunicationsOverview 3 Administrative Radio Conference (EARC) in 1959. The ITUthus provided for the first time a formal process by which radio frequency (RF) spectrum could be allocatedtosupportsatellitecommunication(Pelton1974). Over time, the ITU defined a number of satellite communications services that might be offered via different satellites in different types of orbits. The ITU inter- national processes also defined a system and a process whereby there could be technical coordination of such satellites to limit interference between and among them. The number and type of satellite communications services have grown and expandedovertheyearsasisdiscussedinthefollowingsections(ITU2008). Therearetodaymanytypesoftechnicaldesignsforsatellitecommunications,and thesetechnologiesareoptimizedtosupportavarietyofservicesaroundtheworld.A widerangeofcommercialsatellitesnowoperateatthenational,regional,andglobal level. These satellite systems support various types of data, telephone, television, radio,andvariousnetworkingservicesaroundtheworld. Overview of Commercial Satellite Services The services defined by the International Telecommunication Union (ITU) include thefollowing. Fixed satellite services (FSS): FSS spacecraft support telecommunications ser- vicesbetweenantennasthatareatfixedpoints.Thesefixedantennascanbeusedfor receptiononly,fortwo-waycommunication(likeacableinthesky),orforcommu- nicationswithinanetworkthatcanstartwithonlyafewnodesorcangrowtoavery large network indeed with thousands of interconnected nodes. The first of the commercialcommunicationssatelliteservicesweretheseFSSsystems.TheIntelsat FSS system was the first to begin to provide international commercial telecommu- nications services in 1965. Also deployed in 1965 was the FSS system called Molniya, which provided telecommunications services for the Soviet Union, other SovietSocialistRepublics,andCuba.AnInitialDefenseSatelliteCommunications SatellitesystemwasalsodeployedtoprovideFSSservicestosupportUSdefense- relatedtelecommunicationsservices.TheseinitialFSSsystemshavenowmultiplied tosupportsatellitetelecommunicationsforover200countriesandterritoriesaround theworld(Pelton2006,p.30).Figure1showsacurrentgenerationbroadbandFSS satellite,theIPStarthatoperatesintheAsianregionoftheworld.Figure2depicts theViasat2highthroughputsatellite.Thisrepresentsthehighestcapacitysatelliteof thecurrentgenerationoffixedsatelliteservice(FSS)spacecraftwithacapabilityof about150GB/s.Thisismorethantentimesthethroughputofalargecommunica- tionssatelliteofjust5yearsago. In addition to over 200 commercial communications satellites that supply fixed satellite services, there are now scores of military communications satellites that providefixedsatelliteservicesinsupportofdefense-relatedmissions.Althoughthe largestfleetofdefense-relatedcommunicationssatellitesareownedandoperatedby the US military, there are a number of strategic communications satellite systems ownedbyoveradozencountriesaroundtheworld.Inaddition,commercialsatellite 4 J.N.Pelton Fig.1 TheIPStarSatellitealsoknownasThaicom-4(GraphiccourtesyofIPStar) systems leased capacity to military systems for so-called dual-use purposes to supplement the capabilities of defense satellite communications systems. Figure 2 showstheWGSSmilitarysatellitedesignedtoprovidecommunicationsservices. Broadcastsatelliteservices(BSS):BSSsatellitesuseveryhighpoweredbeamsto deliverradioortelevisionservicesdirectlytoendusers.Inorderforthisservice(also knowninformallyasthedirect broadcastsatellite (DBS) service)tobeeconomical and efficient, the receiver terminals must be small in size, low in cost, and easy to install andoperate.DifferentRFbands areusedforradio ordirect audiobroadcast services (DABS) in contrast to direct broadcast satellite (DBS) television services. The broadcast satellite service began later than the initial FSS offerings, but this industry has grown rapidly and is now by far the largest revenue generator in the satelliteworldbyawidemargin(Pelton2011). TheNimiqBSSsatellite(Fig.3),operatedbytheCanadianTelesatorganization, providesdirectbroadcastservicestoCanadaandtheUSA. Mobilesatelliteservices(MSS):TheMSSservicesprovidetelecommunications to end-user antennas that move rather than remain stationary. The MSS services todayincludetelecommunicationsconnectivityformaritime,aeronautical,andland- basedusers.ThefirstMSSsatellitesweredesignedformaritimeservice.Next,these satelliteswereusedtosupportbothmaritimeandaeronauticalservices.Thelasttype of mobile communications satellites that has evolved are those designed for land- basedmobileservices.ThisisthemostdemandingoftheMSSservicestechnically, SatelliteCommunicationsOverview 5 Fig.2 ThehighthroughputViasat2depictedinorbit(GraphiccourtesyofViasat) butintermsofmarket,thisisalsothemostdemanding.Avarietyofdifferentdesigns in different orbits have evolved with the initial land mobile systems known as Iridium, Globalstar, and ICO experiencing severe financial and market difficulties with their initial service offerings. These organizations have been reorganized and the Iridium and Globalstar systems are deploying their second-generation systems while ICO is developing a new mobile satellite service for the US market (Figs. 4 and5). Today, there are a variety of MSS satellites deployed in a variety of different orbits. Some of the latest systems are those designed to work in conjunction with terrestrialcellulartelephoneserviceswithinurbanareas.Thesehybridsystemsthat integratemobilecommunicationsatelliteswithterrestrialcellularsystemsarecalled MSS with “ancillary terrestrial component (ATC)” in the USA. The equivalent service is called MSS with complementary ground component (CGC) in Europe. These hybrid mobile systems combine urban terrestrial cellular systems ina seam- lessmannertoallowveryhighpoweredMSSsatellitestocovertherestofacountry or region. Unlike the initial constellations like Iridium and Globalstar, these new systemswithaterrestrialcomponentaredeployedingeosynchronousorbitandare targeted to service to a single country like the USA or a single region like Europe (Pelton2006,p.31). 6 J.N.Pelton Fig.3 ThewidebandglobalSatcomsatellite(GraphiccourtesyoftheUSMilitary) These satellite services, FSS, BSS, and MSS, are the so-called big three of the commercial satellite services and represent a very significant part of the total worldwide market for the satellite industry. Nevertheless, there are other types of telecommunication satellite systems that can be, and indeed are, deployed. One additional system is the so-called store and forward type data relay satellite that cansupportmessagingservicestoremoteareas.Themoresatellitesdeployedinlow earth orbit to support in this type of system, the more rapidly a message can be relayed from one part of the world to another. If there are enough satellites of this type,likeintheOrbcommsystem,youcanhavealmostinstantmessaging.Insome cases,thereceivercanbeconfiguredtonotonlyreceiveshortmessagesbutalsoto receive space navigation signals to support vehicular or ship navigation. One can alsodesignatransceivertosendshortdatamessagesaswellastoreceivethem,as has beendone with several store andforwardsatellitesystems. There arealso data relaysatellitesthataretypicallyinGeoorbit.Thesesatellitesaremosttypicallyused torelaydatafromalowearthorbitsystembacktoacentralprocesssothatdatacan becontinuouslycollectedratherthanstoredfordownloadatasubsequenttime.The NASA third generation tracking and data relay satellite that is being deploy in the 2013–2016timeframeisshowninFig.6. SatelliteCommunicationsOverview 7 Fig.4 ACanadianNimiqdirectbroadcastsatellite(GraphiccourtesyofTelesat) Fig.5 Aconstellationof66iridiumsatellitesprovidesglobalmobileservices(Graphiccourtesyof Iridium) Some commercial satellite systems employ what are called cross-links (CLs) or intersatellite links (ISLs), or in ITU parlance intersatellite service (ISS) in order to operate.Thesecanbeusedinlowearthorbitormediumearthorbittointerconnect 8 J.N.Pelton Fig.6 TheNASAthirdgenerationoftrackinganddatarelaysatellite satelliteconstellations.ISLswereapartofthedesignofthelowearthorbitIridium satellitenetwork,and they have been usedin some militarycommunications satel- lites. ISLs could also be used to interconnect geosynchronous satellites on an interregional basis in order to avoid double hops when communicating halfway aroundtheworld.Today,satelliteserviceconnectionsprovidinggloballinkagesand thuscanoftencombinewithafiber-opticsubmarinecabletoachieverapidconnec- tivity across the world. This is true in part since intersatellite links for regional interconnectivity still remain relatively rare. The more common use of ISLs is to interconnect satellites within a large-scale low earth orbit constellation where the satellites are typically hundreds of kilometers apart from one another rather than manythousandsofkilometersapartsuchasthecasewhengeosynchronoussatellites areservingdifferentregionsoftheworld(Pelton2006,p.31). Finally,therearesatellitesformilitaryordefense-relatedcommunications.These satellites for military purposes are allocated different frequency spectrum than commercial satellites. These satellites resemble commercial satellites in many of theirtechnicalfeatures,buttheyoftenhavespecialfeatures.Specialcapabilitiescan 1SeeOslund(2004).
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