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Florida Institute of technologies ECE 5233 Satellite Communications Prepared by: Dr. Ivica Kostanic Lecture 1: Introduction to Satellite Systems (Sections.

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Presentation on theme: "Florida Institute of technologies ECE 5233 Satellite Communications Prepared by: Dr. Ivica Kostanic Lecture 1: Introduction to Satellite Systems (Sections."— Presentation transcript:

1 Florida Institute of technologies ECE 5233 Satellite Communications Prepared by: Dr. Ivica Kostanic Lecture 1: Introduction to Satellite Systems (Sections ) Spring 2014

2 Florida Institute of technologies Page 2  Class overview  Configuration of a satellite systems  Elements of a satellite system  Types of satellite systems  Brief history of satellite communication Outline

3 Florida Institute of technologies Satellite communication system  Satellite system consists of oEarth segment (traffic and control) oSpace segment  Earth segment oService provider hub (ground) oUser terminals  Space segment oSatellite (s) oCommunication links to and from satellites Page 3 1. Data center of the sat-com provider 2. Central hub (receives data stream and sends it toward satellite) 3. Satellite (receives data stream, amplifies and sends it back towards ground) 4. End user antenna – critical part (small size, high performance) 5. Modem – receives data stream 6. User end network – usually IP network

4 Florida Institute of technologies Ground segment  Consists of earth stations  Satellite network may have one or more earth stations  Earth station may be transmit-receive or receive only  Earth stations are connected to terrestrial networks (PSTN for CS traffic or Internet for PS)  Usually have very large antennas (up to 30m in diameter)  Earth stations have high quality and redundant links to terrestrial networks Page 4 Functional block diagram of an earth station Example of a Ku band earth station antenna

5 Florida Institute of technologies Space segment  Satellite consist of oPayload – used in communication oPlatform – facilitates operation of payload  Payload oReceive antenna oElectronics for communication oTransmit antenna  Two types of satellites o“Bent pipes” (transparent) oRegenerative (base band processing)  Smallest assignable recourse oSatellite transponder oSatellite usually hosts multiple transponders oSatellite usually operates in single band (although there are some multiband satellites)  Transmit antenna may be oSingle beam – one area of the Earth oMulti beam – multiple areas of the Earth Page 5 Basics of “bent pipe” architecture Satellite with onboard processing

6 Florida Institute of technologies End user segment  User stations oMobile stations (mobile terminals) oVSAT terminals oGateways (connect space segment to terrestrial networks)  User equipment may oConnect to user stations  Example: Satellite TV oIntegrate with user stations  Example: Satellite phone  Heavily dependent on the end application Page 6 Globstar satellite phones Marine satellite antennas Satellite on the move Satellite TV equipment

7 Florida Institute of technologies Types of satellite orbits  Orbit height oLow Earth Orbit (LEO)  Attitude 160-2,000km  Satellite speed ~ 8km/sec  Orbital period ~ 90 min  Example: Globstar, 48 satellites in six planes, 1413km oMedium Earth Orbit (MEO)  Altitude 2,000km -35,786km  Satellite speed 8km/sec to 3 km/sec  Orbital period 2 to 24h  Example: GPS, 24 satellites in 6 planes, 20,200km oGeosynchronous orbit (GSO)  Altitude 35,768km  Satellite speed ~ 3km/sec  Non zero inclination  Orbital period 24 hours oGeostationary orbit (GEO)  GSO satellite in zero inclination orbit Page 7 Constellation of Globstar system Constellation of GPS system

8 Florida Institute of technologies Satellite services  Fixed satellite services (FSS) oPTP or PTMP delivery of signal across the Globe  Mobile satellite services (MSS) oDelivery of satellite signal to mobile platforms (either terrestrial, marine or aeronautical)  Broadcast satellite services (BSS) oBroadcast of satellite signal (TV, radio)  Navigation satellite services (NAV)  Earth exploration services (ESS)  Space research services (SRS)  Space operations services (SOS)  Radio determination satellite services (RSS)  Inter-satellite services (ISS) Page 8

9 Florida Institute of technologies Frequency bands used for sat-comm  Satellites operate in microwave frequency range  Two links oUplink – ground to satellite oDownlink – satellite to ground  Each link uses its own band  Uplink operates on higher frequency  Microwave frequency bands oL band: 1-2GHz oS band: 2-4GHz oC band: 4-8GHz oX band: 8-12GHz oKu band: 12-18GHz oK band: GHz oKa band: GHz  Majority of existing systems operate in C and Ku  Higher frequencies oMore available spectrum oBetter antenna directivity oHigher propagation losses oMore sophisticated technology Page 9 Frequency chart for communication satellite services

10 Florida Institute of technologies Frequency management  Responsibility of International Telecommunication Union ITU  Insures: oNon-interference condition between different satellite systems oFairness between nations in access to the satellite frequencies  Frequency allocation may be oexclusive for given service oshared between services  Service provisioning usually requires consent of all countries within coverage area of the satellite  Frequency is usually allocated in pairs oOne frequency for UL oOne frequency for DL  UL frequency is higher Page 10 ITU Regions Example: VIASAT license in Ka band as of 2010

11 Florida Institute of technologies Beginnings of satellite communication  Origins: Arthur Clarke’s article in Wireless World in 1945  WW-II stimulated development of two key technologies oMicrowave communication oMissile technology  First satellite launched in 1957 by USSR oSputnik, 83.6kg, LEO, atmospheric studies oMission duration 3 months  First commercial communication satellite 1967 oIntelsat I - EarlyBird, 34.5kg, GEO, communication satellite oCoverage between US and Europe oOperated 4 years (deactivated in 1969) oLaunched from KSC oCould handle 240 voice and 1 TV channel oOwned by Intelsat (52 countries) Page 11 Sputnik 1 Intelsat- EarlyBird

12 Florida Institute of technologies Development of satellite communication  Imagination ( ) oEarly days of extensive scientific research o“Dreaming” of what is possible  Innovation ( ) oEstablishment of governmental space exploration agencies and international satellite consortia oDevelopment of communication and rocket technology oFirst launches  Commercialization ( ) oSatellite communication becomes commercial technology oApplications: cross continental telephony and satellite TV  Liberalization ( ) oTransformation of international governmental consortia oMarket led approach allowed private investments oRegulatory framework changes that allowed all of the transformations to take place  Privatization and private ventures (1990 – on) oCommunication satellites become mainstream technology led by private business oLeading applications: broadcast TV, data backhaul, mobile communications in the air and on the sea, navigation, etc. oFuture – integration of satellite technology with Internet Page 12 Satellite applications (values in B$) History channel documentary: Satellites – how they work https://www.youtube.com/watch?v=eYUxkSFCKZQ


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