14562567-Satellite-Communication.ppt

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Satellite Communication

http://www.final-yearprojects.co.cc/



Satellite

• A satellite is an object that orbits another object (known asits primary). he term is often use! to !escribe an artificialsatellite (as oppose! to natural satellites" or moons).

• #ecause all objects e$ert %ra&ity" the motion of the primaryobject is also affecte! by the satellite. (his obser&ation

allows for the !isco&ery of e$tra solar planets.) 'f twoobjects are sufficiently similar in mass" they are %enerallyreferre! to as a binary system rather than a primary objectan! satellite. he %eneral criterion for an object to be asatellite is that the center of mass of the two objects is

insi!e the other object.

• All masses that are part of the solar system" inclu!in% thearth" are satellites of the Sun" or satellites of those objects"such as the oon.

http://en.wikipedia.org/wiki/Orbit

http://en.wikipedia.org/wiki/Natural_satellite

http://en.wikipedia.org/wiki/Moon

http://en.wikipedia.org/wiki/Extrasolar_planet

http://en.wikipedia.org/wiki/Binary_system_%28astronomy%29

http://en.wikipedia.org/wiki/Center_of_mass

http://en.wikipedia.org/wiki/Solar_system

http://en.wikipedia.org/wiki/Earth

http://en.wikipedia.org/wiki/Sun



http://en.wikipedia.org/wiki/Sun


http://en.wikipedia.org/wiki/Solar_system

http://en.wikipedia.org/wiki/Center_of_mass

http://en.wikipedia.org/wiki/Binary_system_%28astronomy%29

http://en.wikipedia.org/wiki/Extrasolar_planet


http://en.wikipedia.org/wiki/Natural_satellite




*hy +se Satellite,

• Satellite communication is just one example of wirelesscommunication systems. Familiar examples of wirelesssystems are all around us, such as radio and television

broadcasting and mobile and cordless telephones. Thesesystems rely on a network of groundbased transmittersand receivers and for this reason they are often referredto as !terrestrial! systems.

• "ne major use of satellites familiar to everyone is

satellite television broadcasting.• "ther applications of satellite communications include

high speed internet, telephony and corporate networksfor multinational businesses.

"ne major use of satellites familiar to everyone is satellite television broadcasting. The







• A communications satellite (sometimesabbre&iate! to comsat) is an artificial satellite

statione! in space for the purposes oftelecommunications usin% ra!io at microwa&e freuencies. ost communications satellites use%eosynchronous orbits or near-%eostationaryorbits" althou%h some recent systems use lowarth-orbitin% satellites. A place on the %roun!with satellite !ishes use! to transmit to or recei&efrom these is calle! an earth station.

http://en.wikipedia.org/wiki/Satellite

http://en.wikipedia.org/wiki/Telecommunications

http://en.wikipedia.org/wiki/Radio

http://en.wikipedia.org/wiki/Microwave




http://en.wikipedia.org/wiki/Satellite





• Communications satellites pro&i!e a technolo%y

that is complementary to that of fiber opticsubmarine communication cables. +nlike fiberoptic communication" satellite communication hasa propa%ation !elay (also calle! a path !elay) of atleast 0 millisecon!s" which is the time it takesthe ra!io si%nal to tra&el 12"300 km from earth toa satellite an! then back to earth. Satellite 'nternetconnections a&era%e a 400 to 300 millisecon!!elay" about ten times that of a terrestrial 'nternet

link. his !elay is a challen%e for hi%hlyinteracti&e applications such as &i!eo phones"56'7 or first-person shooter online &i!eo %ames.



'ntro!uction

• 'n 894" the American telecommunications

%iant A launche! the worl!;s first true

communications satellite" calle! elstar.Since then" countless communications

satellites ha&e been place! into earth orbit"

an! the technolo%y bein% applie! to them isfore&er %rowin% in sophistication



<reuency #an!s

#an! =ownloa!

#an!s >?

+plink #an!s

>?

+>< (ilitary) 20-0 9-18

C #an!(Commercial)

100-@00 292-4@2

u #an!

(Commercial)

8800-800 8@000-8@200

a #an!(Commercial)

8"00-800 200-10"000

a #an! (ilitary) 000-800 @1200-@2200



Selection of the band

• The selection of the band is not something thatindividual service providers decide, but is rather chosenby large satellite operators based on different factors#

• $vailability# %band is still the most widely availableworldwide. &uband is becoming more available recentlyin regions which were less covered in the past 'South

$merica, $sia, $frica(

• %band is more prone to interference from othertransmission services that share the same fre)uencies'adjacent satellites or terrestrial transmissions( than thehigher bands

• *hile the %band technology is cheaper in itself, itre)uires larger dishes '+ to m( than &u and &aband'-. to +./ m( and therefore imposes relatively higher'installation( costs on the enduser



• &u and especially &aband make better use ofsatellite capacity

• 0igher fre)uency bands '&u and especially&a( suffer significantly more from signaldeterioration caused by rainfall# to ensureavailability in bad weather conditions, thesignal has to be much stronger. 1ote that-.+2 of unavailability means in fact that theservice will be interrupted for almost 3 hoursover a +year period. +2 unavailabilityrepresents 3- hours or almost 4 full days



#an!s of 'nterest

• C-band is the oldest allocation and operates in thefre)uency range around 506 for transmission 'uplink(and between .7 and 4.8 506 for reception 'downlink(.

Ku-band is the most common transmission format in9urope for satellite T: and uses around +4 506 for uplinkand between +-.3 and +8.7; 506 for downlink.

Ka-band uses around - 506 up and between +/ and 8-506 downlink fre)uency.

%band and &uband are becoming congested by anincreasing amount of users, so satellite service operatorsare more and more turning to the use of &aband.



Satellite Communications

1 Satellite Constellations: (microwa&e" strai%htline si%nal propo%ation)

• Bow arth 6rbit (B6) not synchronise! (400to 8400km)

• e!ium arth 6rbit (6) not synchronise!(80000m)

• eosynchronous arth 6rbit (6) (12"00 km)-also known as eostationary)



he 6rbits

• Orbits: GEO, MEO, LEO



he 6

• The most common type of communicationssatellites, particularly the broadcast satelliteslike $friStar, <ntelsat, =an$mSat, 9utelsat and

$ST>$, are in geosynchronous orbit 'from geo? 9arth @ synchronous ? moving at the samerate(. That means that the satellite alwaysstays over one spot on 9arth. <t does this by

placing the satellite in a position ;,7/ kmout in space perpendicularly above thee)uator.



Geostationary Earth

Orbit 36,000 km

Rapid deployment -

instant infrastructure

Affordability



he 6

• $ medium 9arth orbit 'A9"( satellite is onewith an orbit from a few hundred miles to afew thousand miles above the 9arthBs surface.

Satellites of this type are in a higher orbit thanlow 9arth orbit 'C9"( satellites, but lower thangeostationary '59"( satellites. The orbitalperiods 'the time in between two successive

passes over one particular place on 9arth( ofA9" satellites range from about 8 to +8 hours.



he B6

• $ low 9arth orbit 'C9"( satellite system consists of alarge number of satellites each in a circular orbit at aconstant altitude between 8- and /-- km. Decause

they orbit so close to 9arth, they must travel very fastso gravity does not pull them back into the atmosphere.Satellites in C9"s circle around the 9arth at 87,;3 kmper hour. The orbits take the satellites over thegeographic poles. 9ach revolution takes from less than3- minutes up to a few hours. The fleet is arranged insuch a way that from any point on the surface at anytime at least one satellite is in line of sight.



he B6



Types of Satellites

• Astronomical satellites are satellites use!

for obser&ation of !istant planets" %ala$ies"an! other outer space objects.

• Communications satellites are artificial

satellites statione! in space for the purposesof telecommunications usin% ra!io at

microwa&e freuencies. ost

communications satellites use%eosynchronous orbits or near-

%eostationary orbits" althou%h some recent

systems use low arth-orbitin% satellites.

http://en.wikipedia.org/wiki/Astronomical_satellite

http://en.wikipedia.org/wiki/Communications_satellite




http://en.wikipedia.org/wiki/Geosynchronous_orbit

http://en.wikipedia.org/wiki/Geostationary_orbit

http://en.wikipedia.org/wiki/Low_Earth_orbiting_satellite

http://en.wikipedia.org/wiki/Low_Earth_orbiting_satellite

http://en.wikipedia.org/wiki/Geostationary_orbit

http://en.wikipedia.org/wiki/Geosynchronous_orbit





http://en.wikipedia.org/wiki/Astronomical_satellite



• Earth observation satellites are satellitesspecifically !esi%ne! to obser&e arth from orbit"

similar to reconnaissance satellites but inten!e! fornon-military uses such as en&ironmental monitorin%" meteorolo%y" map makin% etc.

• Navigation satellites are satellites which use ra!io

time si%nals transmitte! to enable mobile recei&erson the %roun! to !etermine their e$act location.he relati&ely clear line of si%ht between thesatellites an! recei&ers on the %roun!" combine!

with e&er-impro&in% electronics" allows satellitena&i%ation systems to measure location toaccuracies on the or!er of a few metres in realtime.

http://en.wikipedia.org/wiki/Earth_observation_satellite



http://en.wikipedia.org/wiki/Reconnaissance_satellite

http://en.wikipedia.org/wiki/Environment

http://en.wikipedia.org/wiki/Meteorology

http://en.wikipedia.org/wiki/Map_making

http://en.wikipedia.org/wiki/Navigation_satellite


http://en.wikipedia.org/wiki/Metre

http://en.wikipedia.org/wiki/Metre


http://en.wikipedia.org/wiki/Navigation_satellite

http://en.wikipedia.org/wiki/Map_making

http://en.wikipedia.org/wiki/Meteorology

http://en.wikipedia.org/wiki/Environment







• Reconnaissance satellites are

arth obser&ation satellite or

communications satellite !eploye! for military or

intelli%ence applications.

• Space stations are man-ma!e structures that are

!esi%ne! for human bein%s to li&e on in

outer space. A space station is !istin%uishe! fromother manne! spacecraft by its lack of major

propulsion or lan!in% facilities - instea!" other

&ehicles are use! as transport to an! from the

station. Space stations are !esi%ne! for me!ium-term li&in% in orbit" for perio!s of weeks" months"

or e&en years.




http://en.wikipedia.org/wiki/Military

http://en.wikipedia.org/wiki/Espionage

http://en.wikipedia.org/wiki/Space_station

http://en.wikipedia.org/wiki/Human

http://en.wikipedia.org/wiki/Outer_space

http://en.wikipedia.org/wiki/Spacecraft

http://en.wikipedia.org/wiki/Spacecraft_propulsion

http://en.wikipedia.org/wiki/Landing


http://en.wikipedia.org/wiki/Week

http://en.wikipedia.org/wiki/Month

http://en.wikipedia.org/wiki/Year

http://en.wikipedia.org/wiki/Year

http://en.wikipedia.org/wiki/Month

http://en.wikipedia.org/wiki/Week


http://en.wikipedia.org/wiki/Landing

http://en.wikipedia.org/wiki/Spacecraft_propulsion

http://en.wikipedia.org/wiki/Spacecraft

http://en.wikipedia.org/wiki/Outer_space

http://en.wikipedia.org/wiki/Human

http://en.wikipedia.org/wiki/Space_station

http://en.wikipedia.org/wiki/Espionage

http://en.wikipedia.org/wiki/Military






• Weather satellites are satellites that primarily areuse! to monitor the weather an!/or climate of the

arth.• Drag-free satellites are satellites that offers an

en&ironment that is as isolate! as possible fromthe forces of nature. A properly !esi%ne! !ra%-

free-satellite proof mass is uncouple! from the restof the +ni&erse to a remarkable !e%ree.

• Miniaturie!"Satellites are satellites of unusuallylow wei%hts an! small si?es. Dew classifications

are use! to cate%orie?e these satellites:minisatellite (200-00k%)" microsatellite (below800k%)" nanosatellite (below 80k%).

http://en.wikipedia.org/wiki/Weather_satellite

http://en.wikipedia.org/wiki/Weather

http://en.wikipedia.org/wiki/Climate


http://en.wikipedia.org/wiki/Drag-free_satellite

http://en.wikipedia.org/wiki/Miniaturized_Satellites

http://en.wikipedia.org/wiki/Miniaturized_Satellites

http://en.wikipedia.org/wiki/Drag-free_satellite


http://en.wikipedia.org/wiki/Climate

http://en.wikipedia.org/wiki/Weather

http://en.wikipedia.org/wiki/Weather_satellite



A Selective Communications Satellite

Chronology

• 89@2 Arthur C. Clarke Article: E$tra-errestrialFelaysE

• 8922 Gohn F. 7ierce Article: E6rbital Fa!ioFelaysE

• 8924 <irst rans-Atlantic elephone Cable: A-8

• 892 Sputnik: Fussia launches the first earth

satellite.• 8940 8st Successful =BA Baunch 5ehicle



• 8940 A applies to <CC for e$perimental satellitecommunications license

• 8948 <ormal start of BSAF" FBAH" an!SHDC6 7ro%rams

• 894 BSAF an! FBAH launche!

• 894 Communications Satellite Act (+.S.)

• 8941 SHDC6 launche!

• 894@ 'DBSA forme!

• 8942 C6SA;s AFBH #'F=: 8st commercialcommunications satellite



• 8949 'DBSA-''' series pro&i!es %lobal

co&era%e• 89 AD': 8st =omestic Communications

Satellite (Cana!a)

• 89@ *SAF: 8st +.S. =omestic

Communications Satellite• 892 'DBSA-'5A: 8st use of !ual-polari?ation

• 892 FCA SAC6: 8st operational bo!y-stabili?e! comm. satellite

• 894 AF'SA: 8st mobile communicationssatellite



• 894 7ABA7A: 1r! country ('n!onesia) to

launch !omestic comm. satellite

• 899 'DAFSA forme!.

• 8933 A-3: 8st <iber-6ptic rans-Atlantic

telephone cable



#asic Elements

Satellite communications are comprise! of

main components:

•The Satellite •The $roun! Station%



he arth Station



he arth Station

• 9arth station is the common name for every installationlocated on the 9arthBs surface and intended forcommunication 'transmission andEor reception( with oneor more satellites.

• 9arth stations include all devices and installations forsatellite communications# handheld devices for mobilesatellite telephony, briefcase satellite phones, satellite T:reception, as well as installations that are less familiar,eg :S$T stations and satellite broadcast T: stations.

• The term 9arth station refers to the collection ofe)uipment that is needed to perform communications viasatellite# the antenna 'often a dish( and the associatede)uipment 'receiverEdecoder, transmitter(.



arth Stations

>i%h Capacity Stations - Costly" comple$

Ser&ices communities lar%e enou%h to reuire

fee!er line access to the arth Station

i!-Capacity SS - +se! by Corporations for 7ri&ate Detworks

5i!eoconferencin%" electronic mail" !ata"

5oice Ser&ices. ach earth station can be

connecte! to any other station in the network.

5SA Detwork - 6ne aster arth Station an! many 5SA

terminals sharin% the S. Bimite! to !ata

transmissions" !i%ital &oice an! !i%ital &i!eo.

Fecei&e-6nly arth Station - 5oice only" =ata only" 5 Fecei&e only or a

combination.



The parts in the sky

• The two main parts in the sky common to all satellitesare called the payload and the bus.

Payload: transponders, antennas

Bus: physical platform, remote control



he 7ayloa!

• The payload represents all e)uipment asatellite needs to do its job. This can includeantennas, cameras, radar and electronics.

• The payload is different for every satellite. Forexample, the payload for a weather satelliteincludes cameras to take pictures of cloudformations, while the payload for acommunications satellite includes largeantennas to transmit T: or telephone signals

to 9arth.



he ranspon!er

• The transponder is the key component for satellitecommunications# it is the part of the payload that takesthe signals received from the transmitting 9arth station,filters and translates these signals and then redirectsthem to the transmitting antenna on board.%ommunications satellites carry a large number oftransponders on board 'normally from six to more than84(, enabling them to deliver multiple channels ofcommunication at the same time. These channels are

called carriers.



he Antenna

• $ntennas that receive the original signal fromthe transmitting 9arth station and retransmitthis signal to the receive stations on 9arth.

• The antennas that were used in the past to dothis were omnidirectional 'transmittingsignals in every direction( and not veryeffective. They were replaced by more efficient

highgain antennas 'most often dish shaped(pointing )uite precisely towards the areas theywere servicing.



he #us

• The bus is the part of the satellite that carriesthe payload and all its e)uipment into space.<t is the physical platform that holds all the

satelliteBs parts together and that provideselectrical power, navigation, control andpropulsion to the spacecraft. The bus alsocontains e)uipment that allows the satellite to

communicate with 9arth, a kind of BremotecontrolB.







he 7S

• he nominal 7S 6perational Constellation consists of @satellites that orbit the earth in 8 hours. here are often morethan @ operational satellites as new ones are launche! to

replace ol!er satellites. he satellite orbits repeat almost thesame %roun! track (as the earth turns beneath them) once each!ay. he orbit altitu!e is such that the satellites repeat the sametrack an! confi%uration o&er any point appro$imately each @hours (@ minutes earlier each !ay). here are si$ orbital planes(with nominally four S5s in each)" eually space! (40 !e%reesapart)" an! incline! at about fifty-fi&e !e%rees with respect tothe euatorial plane. his constellation pro&i!es the user with between fi&e an! ei%ht S5s &isible from any point on the earth.





So *hat is he 'nternet ,

• 't is a comple$ web of networks.

• ach network can ha&e millions of inter-connecte!computers which use telephone infrastructure tocommunicate

• Do one IownsJ the 'nternet - 'ts backbone" throu%h whichinformation flows" is owne! by a number of pri&atecompanies

• essa%es are transmitte! throu%h the 'nternet &ia a computerlan%ua%e calle! Itransmission control protocol - C7/'7.

• ach messa%e tra&els as a packet an! has a co!e! a!!resswhich tells the network its !estination an! also has a block of!ata content



• his packet is transmitte! &ia &ariety of routes

• =ata tra&els more efficiently usin% !i%ital techniues

• elstra has been (slowly) !i%itisin% its public switche!telephone network

>ow !o home computers link to the 'nternet ,• Dormally &ia an 'nternet Ser&er 7ro&i!er ('S7) - a

monthly fee is char%e! for connection an!maintenance

• hese 'S7Js are connecte! to a lar%er network ser&ice- Detwork Ser&ice 7ro&i!ers (DS7Js) which areconnecte! usin% fibre optic cable 6F satellite links.



• here are about 900 'S7s operatin% in Australia

• elstra has a lar%e share of the 'nternet wholesalemarket

• ost 'S7s are small an! operate a sin%le point

presence or I767J - this is a location which

comprises mo!ems an! a network connection into

which an 'S7Js customers !ial to make an 'nternet

connection.

• >i%h spee! 'nternet reuires 'S=D





Applications of SattComm• Radio and TV Broadcasting

• Business radio and TV

• Telephony

• Thin route or trunk telephony

• Aobile satellite telephony• LEO-based telephony

• GEO-based telephony

• Data, broadband and multimedia services

• <= over satellite for <S=s

• %orporate or institutional :S$T networks

• 9nduser services for home or small office

• Aobile data communications



Radio and TV Broadcasting• The most familiar use of satellites is television

broadcasting. T: satellites deliver hundreds oftelevision channels every day throughout theworld. These satellites are even used to supplytelevision signals to terrestrial transmitters orcablehead end stations for further distribution

to the home, or to exchange signals betweentelevision studios. The bandwidth re)uired totransmit multiple programmes at the sametime can easily be provided using satellites.



Satellite =ish Antenna



The Eutelsat HotBird position at13 Degrees East



Business radio and TV

• igital television has made it possible todistribute information within organisations andcompanies that are geographically dispersed,

or to deliver distance education. Similarly,digital radio allows for the delivery of radioservices to relatively small closed user groups.



Thin route or trunk telephony

• Telecom operators have been using satellitecommunications for many years to carry longdistance telephone communications, especially

intercontinental, to complement or to bypasssubmarine cables. To the enduser this istransparent# the phone calls are routedautomatically via the available capacity at any

given moment



Aobile satellite telephony

• Aobile telephony allows the user to make telephonecalls and to transmit and receive data from whereverheEshe is located. igital cellular mobile telephony suchas 5SA has become a worldwide standard for mobilecommunications, but its services lack coverage overareas that are sparsely populated or uninhabited'mountains, jungle, sea(, because it is not economicallyviable or practical for the network operators to buildantennas there. Satellite telephony seems to be able to

provide a possible solution to the problem of providingvoice and data communications services to these otherlocations



LEO-based telephony

• $nother mobile satellite communications system is the5lobalstar satellite telephone network. 5lobalstar, whichwas established in +33+ and began commercial servicein late +333, offers service from virtually anywhereacross over +-- countries, as well as from mostterritorial waters and several midocean regions.5lobalstar deploys handheld telephone sets that switchbetween the terrestrial wireless telephone network'5SA( and a C9"based satellite network in places

where no terrestrial 5SA network is available.





GEO-based telephony

• $n alternative approach to satellite telephony uses ageostationary satellite instead of the C9". This results inlonger delays 'approximately half a second( butswitching on board the satellite reduces thisinconvenience as much as possible. The Thuraya mobilesatellite system was launched in +33+, its satellitemaintains a geosynchronous orbit at 44 degrees 9ast.Thuraya operates effectively in both satellite and 5SAenvironments. <ts satellite network capacity is about

+,7;- telephone channels. *hen within reach of a5SA network, ThurayaBs mobile phone acts as anordinary 5SA handset.



Satellite 7hones



ll f



<= over satellite for <S=s

• Telecoms and connectivity providers have started usingsatellite communications to bypass the increasinglyclogged terrestrial and submarine networks tocomplement their backbone connectivity or to

supplement them where they are not yet available. Thisapproach takes advantage of the fact that satellite isnot a real pointtopoint connection like cable, but aconnection that allows the delivery to multiple points atthe same time. This allows for simultaneous updating of

multiple caching, proxy or mirroring servers.





<n uch the same way" it is possible to push 'nternet content toan! e&en o&er the e!%es of e$istin% networks. *hen it is

necessary to pro&i!e lar%e amounts of content to places that are

poorly connecte! to the 'nternet" it is now possible to push

content to local 7o7s (7oint of 7resence) e!%e ser&ers. hese can

then in turn ser&e as 'S7s to the local users or user communities

%orporate or institutional :S$T



%orporate or institutional :S$Tnetworks

• :S$T stands for :ery Small $perture Terminal andrefers to combined sendEreceive terminals with a typicalantenna diameter of + to .7 m linking the central hubto all remote offices and facilities and keeping them all

in constant immediate contact. :S$T networks offersolutions for large networks with low or medium traffic.They provide very efficient pointtomultipointcommunication, are easy to install and can be expandedat low extra cost. :S$T networks offer immediateaccessibility and continuous high)uality transmissions.

They are adapted for any kind of transmission, fromdata to voice, fax and video.



VSAT Star-shaped Networks



• $ :S$T network, a corporation can communicate freelyand constantly with branch offices#

• :oice and fax transmissions

• Cocal $rea 1etwork interconnection

• ata broadcasting

• :ideoconferencing• <nhouse training



VSAT Mesh-shaped Networks

O S t llit ! t t



One-wa Satellite !nternet"onne#tion



Two-wa Satellite !nternet"onne#tion



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14562567-Satellite-Communication.ppt