satellite communications

Satellite CommunicationLecture-1

Dr Shahab Ahmad Niazi

Satellite CommunicationsIntroduction bull General conceptsbull Needs advantages and

disadvantagesbull Satellite characteristicsbull Orbitsbull Earth coveragebull System components and designbull Power sourcesbull Communication characteristics

Spectrum and Bandwidth Channel capacity Frequency and Wavelength Path losses

Antennas and beam shaping

Text

bull Course BookSatellite Communications 4th Edition

Dennis RoddyReference Books

1 Satellite Communications 2nd Edition T Pratt C Bostian and J Allnut

2 Satellite Communications Systems 5th Ed

Gerard Maral Michel Bousquet

Why Satellite Communication

bull The Earth is a sphere amp The microwave frequencies travel in straight line but to connect two regions very far away on the two side of the sphere the link requires lot of repeaters because of Earthrsquos curvature

bull A single satellite can do the magic linking the continents with one repeater

Motivation to use the Sky

Regions of Space

Space is defined as a place free from obstacles

It can be divided into three regions

bull Air Space -gt region below 100 km from earthrsquos surface

bull Outer Space -gt also called cosmic space and ranges from 100 km up till 42 000 km It is mostly used by

communication satellites

bull Deep Space -gt Regions beyond 42000 km fall in this category

Satellite

bull It is a repeater which receives signal from Earth at one frequency amplify it amp transmit it back to Earth at other frequency

EARTH STATION

bull There are two earth station in a simple Satellite communication link One transmits the signal to satellite called transmitting Earth station

bull The other receives the signal from satellite called receiving Earth Station

UPLINK amp DOWN LINK

bull The communication link from Transmitting earth station to satellite is called Up-link

bull The communication link from satellite To receiving earth station is called Down-link

What is a satellite system

bull A satellite system consists of one or more satellites a ground-based station to control the operation of the system and a user network earth stations that provides the interface facilities for the transmission and reception of terrestrial communications traffic

How a satellite works

bull A satellite stays in orbit because the gravitational pull of the earth balanced by the centripetal forceof the revolving satellite

bull One Earth station transmits the signals to the satellite at Up link frequency Up link frequency is the frequency at which Earth station is communicating with a satellite

bull The satellite transponder process the signal and sends it to the second Earth station at another frequency called downlink frequency

Advantages of Satellite Communications over Terrestrial Communications

bull The coverage area greatly exceedsbull Transmission cost of a satellite is independent

of the distance from the center of the coverage area

bull Satellite-to-satellite communication is very precise

bull Higher bandwidths are available for use

Disadvantages of Satellite Communications

bull Launching satellites into orbits is costly

bull Satellite bandwidth is gradually becoming used up

bull The propagation delay is larger

Active and Passive Satellites

bull Active satellites are used for linking and also for processing the signals

The linkage is known as bent pipe technology where processing like frequency translation power amplification etc take place

Active satellites employ lsquoRegenerative Technologyrsquo which consists of demodulation processing frequency translation switching and power amplification are carried out Block used for this purpose is called transponder

bull Passive satellites do-not have on-board processing and are just used to link two stations through space

Low cost - Loss of power ndash not useful for communication applications

Historical Overviewbull 1945 Theorist named Clarke studied that satellite orbiting in equatorial orbit

at radius of approx 42000 km would look as if stationary if moving at a specific speed 3 satellites at a space of 120 degree apart can cover the whole world Evolution of the concept of GEO

1950rsquos ndashPutting the pieces together

10487081956 -Trans-Atlantic cable opened (about 12 telephone channels per operator)

10487081957 First man-made satellite launched by former USSR (Sputnik-1 LEO) It was used to identify atmospheric density of various orbital layers It provided data about radio signal distribution in ionosphere

10487081958 First US satellite launched (SCORE) First voice communication established via satellite (LEO lasted 35

days in orbit)

bull 1960rsquos ndashFirst satellite communicationsbull 10487081960 First passive communication satellite (Large

balloons Echo I and II)bull 10487081962 First active communication satellite (Telstar I

MEO)bull 10487081963 First satellite into geostationary (GEO) orbit

(Syncom1 communication failed)bull 10487081964 International Telecomm Satellite Organization

(INTELSAT) createdbull 10487081965 First successful communications GEO (Early

Bird INTELSAT 1)

Historical Overview

bull 1970rsquos ndashGEO Applications Development DBS10487081972 First domestic satellite system operational (Canada)10487081975 First successful direct broadcast experiment (USA-India)10487081977 A plan for direct broadcast satellites (DBS) assigned by the ITU10487081979 International Mobile Satellite Organization (Inmarsat) established

Historical Overview

bull 1980rsquos ndashGEO Applications Expanded Mobile10487081981 First reusable launch vehicle flight10487081982 International maritime communications made operational10487081984 First direct-to-home broadcast system operational (Japan)10487081987 Successful trials of land-mobile communications (Inmarsat)10487081989-90 Global mobile communication service extended to land mobile and aeronautical use (Inmarsat)

Historical Overview

bull 1990+rsquos NGSO applications development and GEO expansion1990-951048708Proposals of non-geostationary (NGSO) systems for mobile communications1048708Continuing growth of VSATs around the world1048708Spectrum allocation for non-GEO systems1048708Continuing growth of DBS DirectTV created19971048708Launch of first batch of LEO for hand-held terminals (Iridium)1048708Voice-service portables and paging-service pocket size mobile terminals launched (Inmarsat)1998-2000 Mobile LEO systems initiate service and fail afterwards (IridiumGlobalstar)

Historical Overview

Altitudes of orbits above the earth

bull There are 3 common types of satellite based on altitude ie GEO MEO amp LEOOrbit Altitude Missions possible

Low-Earth orbit LEO 250 to 1500 km

Earth observation meteorology

telecommunications (constellations)

Medium-Earth orbit MEO

10000 to 30000 km Telecommunications

(constellations) positioning science

Geostationary Earth orbit GEO

35786 km Telecommunications positioning science

Elliptical orbit Between 800 and

27000 km Telecommunications

Hyperbolic orbit Up to several million

km Interplanetary missions

ITU Frequency Spectrum Allocations

Communication Satellites

bull Another issue is the presence of the Van Allen belts - layers of highly charged particles trapped by the earths magnetic field

bull Any satellite flying within them would be destroyed fairly quickly by the highly-energetic charged particles trapped there by the earths magnetic field

bull Hence there are three regions in which satellites can be placed safely - illustrated in the following figure


Communication satellites and some of their properties including altitude above the earth round-trip delay time and number of satellites needed for global coverage


Geostationary Satellites

bull Each downward beam can be focused on a small geographical area so multiple upward and downward transmissions can take place simultaneously

bull Typically the spot beams are elliptically shaped and can be as small as a few hundred km in diameter

bull A communication satellite for the United States typically has one wide beam for the contiguous 48 states plus spot beams for Alaska and Hawaii

VSAT systems

bull VSAT (Very Small Aperture Terminal) ndash a satellite communication system that serves home and business users for data voice and video signals

bull Tiny terminals have 1-meter or smaller antennas (versus 10 m for a standard GEO antenna) and can put out about 1 watt of power

bull A VSAT end user has a box that interfaces between the users computer and an outside antenna with a transceiver

bull The tranceiver receives sends a signal to a satellite transponder

Medium-Earth Orbit Satellites

bull The MEO (Medium-Earth Orbit) satellites are between the two Van Allen belts

bull Takes something like 6 hours to circle the earthbull As MEO are lower than the GEOs (typically

16000 km above Earth) they have a smaller footprint on the ground and require less powerful transmitters to reach them

bull Currently they are not used for telecommunications but in navigation systems


bull The 24 GPS (Global Positioning System) satellites orbiting at about 18000 km are American but free to use by anyone

bull Russia is using Glonass ndash 24 satellites orbiting at 19100 km

bull European Union works on Galileo ndash 30 satellite MEO navigation system orbiting at 23200 km - global navigation satellite system (GNSS) (2019)

bull China is building Compass ndash 35 satellites ndash 5 GEO and 30 MEO at 21100 km (10 in use and offering services now) (2020)

Low-Earth Orbit Satellitesbull A Low Earth Orbit (LEO) is generally defined as

an orbit below an altitude of approximately 2000 kilometers and above 160 kilometers ndash almost all human spaceflights have taken place in LEO

bull (-) large numbers of LEO are needed for a complete system due to their rapid motion (26000 to 27000 km per hour)

bull (+) satellites are very close to the earth so the ground stations do not need much power

bull (+) the round-trip delay is only a few milliseconds

Low-Earth Orbit Satellites

bull Because these LEO orbits are not geostationary a network (or constellation) of satellites is required to provide continuous coverage

bull LEOs are used for a variety of civil scientific and military roles including Earth observation radar optical telecoms and demonstrator

bull Some use as many as 66 satellites (Iridium ndash satellite phones)

Low-Earth Orbit Satellitesbull The Iridium satellite constellation - group of

satellites providing voice and data coverage to satellite phones pagers and integrated transceivers over Earths entire surface

bull Originally developed in 1992 services started in 1998 bankrupted in August 1999 and subsequently restarted in March 2001 (513 000 subscribers in 2011)

bull Satellites are at a height of approximately 781 kmbull Customers include the maritime aviation and oil

exploration industries as well as people traveling in parts of the world lacking a telecommunications infrastructure (eg deserts mountains jungles and some Third World countries)

Iridium

bull The Iridium satellites are in circular polar orbits

bull They are arranged in north-south necklaces with one satellite every 32 degrees of latitude

bull With six satellite necklaces the entire earth is covered

bull Each satellite can support up to 1100 concurrent phone calls and weighs about 680 kg

Iridium

bull Each satellite has a maximum of 48 cells (spot beams) with a total of 1628 cells over the surface of the earth

bull Each satellite has a capacity of 3840 channels or 253440 in all

bull Some of these are used for paging and navigation while others are used for data and voice

bull An interesting property of Iridium is that communication between distant customers takes place in space with one satellite relaying data to the next one

bull A caller at the North Pole contacts a satellite directly overhead - the call is relayed via other satellites and finally sent down to the called at the South Pole

Globalstar

bull Globalstar - based on 48 LEO satellites but uses a different switching scheme than that of Iridium (relays calls from satellite to satellite which requires sophisticated switching equipment in the satellites)

bull Globalstar uses a traditional bent-pipe design - a call originating at the North Pole is sent back to earth and picked up by the large ground station

bull The call is then routed via a terrestrial network to the ground station nearest the callee and delivered by a bent-pipe connection as shown

bull Advantage - puts much of the complexity on the ground where it is easier to manage (412300 subscribers in 2010)

Teledesic

bull Teledesic was as high-speed wireless switched global network -an IP-based system designed to support data voice and video at the same quality level as fiber-based terrestrial systems - a global Internet-in-the-Skyldquo providing broadband and Internet access

bull Originally (1995) planning 840 active satellites with in-orbit spares at an altitude of 700 km

bull Scaled (1997) to 288 active satellites at 1400 kmbull Officially suspended its satellite construction work on

October 1 2002bull Funding from Microsoft (investing US$30 million for an

85 stake) Craig McCaw Bill Gates Paul Allen and Saudi prince Alwaleed bin Talal and for achieving allocation on the Ka-band frequency spectrum for non-geostationary services

Highly elliptical orbit

bull HEO ndash an elliptic orbit with a low-altitude (about 1000 kilometres) perigee and a high-altitude (over 35786 kilometres) apogee

bull Advantage - long dwell times at a point in the sky during the approach to and descent from apogee - phenomenon known as apogee dwell (acts like GEO) (3-4 hours can receive signal with 06 m antenna)

bull Used by Sirius Satellite Radio (operating in North America) the Molniya communication satelites (at least 3) (Russia)

Satellite Applications

bull Communication The main application for satellites today is in communication Communication satellites act as relay stations in the sky and permit reliable long-distance communication worldwide

bull Direct Broadcast Satellite (DBS) service This is a TV signal distribution system designed to distribute signals directly to consumers


bull Satellite Cell Phones Satellite-based cellular telephone service is under development The proposed new systems use low-earth-orbit satellites to perform the relay services to the main telephone system or to make connection directly between any two cellular telephones using the system


bull Digital Satellite Radio One of the newest satellite applications is in digital satellite radio or the digital audio radio service (DARS) ndash This service provides hundreds of channels of

music news sports and talk radio to car portable and home radios

ndash It provides full continuous coverage of the station you select wherever you are in the United States

ndash Its digital transmission techniques ensure high-quality stereo sound that is immune to noise

ndash The satellites transmit other information such as song title and artist type of music and other data which are displayed on a LCD screen


bull Surveillance satellites can look at the earth and transmit what they see back to ground stations for a wide variety of purposes including military intelligence meteorological applications and mapping

bull Satellite navigation systems can provide global coverage unavailable with land-based systems satellites

Global Positioning System

bull The Global Positioning System (GPS) also known as Navstar is a satellite-based navigation system that can be used by anyone with an appropriate receiver to pinpoint his or her location on earth

bull GPS was developed by the US Air Force for the Department of Defense as a continuous global radio navigation system

bull The GPS system consists of three major segments the space segment the control segment and the user segment


Space Segmentndash The space segment is the constellation of

satellites orbiting above the earth that contain transmitters which send highly accurate timing information to GPS receivers on earth

bull The GPS consists of 24 main operational satellites and 3 active spare satellites arranged in six orbits of 3 or 4 satellites each


Space Segmentbull Each of the satellites contains four highly accurate

atomic clocks

bull These clocks are used to generate a unique pseudorandom code identifying the specific satellite that is transmitted to earth

bull The satellite also transmits a set of digitally coded ephemeris data that completely defines its precise orbit


The GPS space segment


Control Segmentndash The control segment of the GPS system

refers to the various ground stations that monitor the satellites and provide control and update information

bull The master control station is operated by the US Air Force in Colorado Springs

bull Four additional monitoring and control stations constantly monitor the satellites and collect range information from each


Control Segmentbull The information is sent back to the master

control station in Colorado where all the information is collected and position data on each satellite calculated

bull The master control station then transmits new ephemeris and clock data to each satellite on the S-band uplink once per day


GPS Receiversndash A GPS receiver is a complex superheterodyne

microwave receiver designed to pick up the GPS signals decode them and then compute the location of the receiver

ndash The output is usually an LCD display giving latitude longitude and altitude information andor a map of the area

ndash The most widely used GPS receiver is the popular handheld portable type not much larger than an oversized handheld calculator


GPS Receiversndash The receiver performs a time multiplexing

operation on the four satellites within view of the receiver

ndash The data is extracted from each of the four satellites and stored in the receiverrsquos memory

ndash Data from three satellites is needed to fix the receiverrsquos position

ndash If data from a fourth satellite is available altitude can be calculated


GPS receiver


How triangulation works to locate a GPS receiver


GPS Applications ndash The primary application of the GPS is

military and related navigationndash GPS is used by all services for ships

aircraft and ground troopsndash Most civilian applications also involve

navigation which is usually marine or aviation-related


GPS Applications

ndash Commercial applications include surveying mapmaking and construction

ndash Vehicle location is a growing application for trucking and delivery companies taxi bus and train transportation

ndash Police fire ambulance and forest services also use GPS

ndash A new hobby called geocaching uses GPS receivers In this sport one team hides an item or ldquotreasurerdquo and then gives the other team coordinates to follow to find the treasure within a given time

Design of the Satellite Link

bull The satellite link is probably the most basic in microwave communications since a line-of-sight path typically exists between the Earth and space

bull This means that an imaginary line extending between the transmitting or receiving Earth station and the satellite antenna passes only through the atmosphere and not ground obstacles

bull Such a link is governed by free-space propagation with only limited variation with respect to time due to various constituents of the atmosphere


bull Free-space attenuation is determined by the inverse square law which states that the power

received is inversely proportional to the square of the distance

bull The same law applies to the amount of light that reaches our eyes from a distant point source such as an automobile headlight or star

bull There are however a number of additional effects that produce a significant amount of degradation and time variation

bull These include rain terrain effects such as absorption by trees and walls and some less-obvious impairment produced by unstable conditions of the air and ionosphere


bull It is the job of the communication engineer to identify all of the significant contributions to performance and make sure that they are properly taken into account

bull The required factors include the performance of the satellite itself the configuration and performance of the uplink and downlink Earth stations and the impact of the propagation medium in the frequency band of interest

Satellite Communication Lecture-1

Satellite Communications

Text



Regions of Space

Satellite

EARTH STATION




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Satellite CommunicationsIntroduction bull General conceptsbull Needs advantages and

disadvantagesbull Satellite characteristicsbull Orbitsbull Earth coveragebull System components and designbull Power sourcesbull Communication characteristics

Spectrum and Bandwidth Channel capacity Frequency and Wavelength Path losses

Antennas and beam shaping

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Regions of Space







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EARTH STATION

































days in orbit)






Bird INTELSAT 1)

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Teledesic



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Regions of Space







Satellite


EARTH STATION

































days in orbit)






Bird INTELSAT 1)

Historical Overview


Historical Overview


Historical Overview


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VSAT systems





























Iridium





Iridium






Globalstar





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Satellite

EARTH STATION








Historical Overview

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VSAT systems


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Iridium

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Globalstar

Teledesic



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Satellite


EARTH STATION

































days in orbit)






Bird INTELSAT 1)

Historical Overview


Historical Overview


Historical Overview


Historical Overview



























VSAT systems





























Iridium





Iridium






Globalstar





Teledesic


































atomic clocks


























GPS receiver









GPS Applications




















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Regions of Space

Satellite

EARTH STATION








Historical Overview

Slide 17

Slide 18

Slide 19

Slide 20




Slide 24

Slide 25


VSAT systems


Slide 29


Slide 31

Slide 32

Iridium

Slide 34

Globalstar

Teledesic



Slide 39

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Slide 43

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EARTH STATION

































days in orbit)






Bird INTELSAT 1)

Historical Overview


Historical Overview


Historical Overview


Historical Overview



























VSAT systems





























Iridium





Iridium






Globalstar





Teledesic


































atomic clocks


























GPS receiver









GPS Applications




















Text



Regions of Space

Satellite

EARTH STATION








Historical Overview

Slide 17

Slide 18

Slide 19

Slide 20




Slide 24

Slide 25


VSAT systems


Slide 29


Slide 31

Slide 32

Iridium

Slide 34

Globalstar

Teledesic



Slide 39

Slide 40

Slide 41


Slide 43

Slide 44

Slide 45

Slide 46

Slide 47

Slide 48

Slide 49

Slide 50

Slide 51

Slide 52

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Slide 55

Slide 56































days in orbit)






Bird INTELSAT 1)

Historical Overview


Historical Overview


Historical Overview


Historical Overview



























VSAT systems





























Iridium





Iridium






Globalstar





Teledesic


































atomic clocks


























GPS receiver









GPS Applications




















Text



Regions of Space

Satellite

EARTH STATION








Historical Overview

Slide 17

Slide 18

Slide 19

Slide 20




Slide 24

Slide 25


VSAT systems


Slide 29


Slide 31

Slide 32

Iridium

Slide 34

Globalstar

Teledesic



Slide 39

Slide 40

Slide 41


Slide 43

Slide 44

Slide 45

Slide 46

Slide 47

Slide 48

Slide 49

Slide 50

Slide 51

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Bird INTELSAT 1)

Historical Overview


Historical Overview


Historical Overview


Historical Overview



























VSAT systems





























Iridium





Iridium






Globalstar





Teledesic


































atomic clocks


























GPS receiver









GPS Applications




















Text



Regions of Space

Satellite

EARTH STATION








Historical Overview

Slide 17

Slide 18

Slide 19

Slide 20




Slide 24

Slide 25


VSAT systems


Slide 29


Slide 31

Slide 32

Iridium

Slide 34

Globalstar

Teledesic



Slide 39

Slide 40

Slide 41


Slide 43

Slide 44

Slide 45

Slide 46

Slide 47

Slide 48

Slide 49

Slide 50

Slide 51

Slide 52

Slide 53


Slide 55

Slide 56


Historical Overview


Historical Overview


Historical Overview



























VSAT systems





























Iridium





Iridium






Globalstar





Teledesic


































atomic clocks


























GPS receiver









GPS Applications




















Text



Regions of Space

Satellite

EARTH STATION








Historical Overview

Slide 17

Slide 18

Slide 19

Slide 20




Slide 24

Slide 25


VSAT systems


Slide 29


Slide 31

Slide 32

Iridium

Slide 34

Globalstar

Teledesic



Slide 39

Slide 40

Slide 41


Slide 43

Slide 44

Slide 45

Slide 46

Slide 47

Slide 48

Slide 49

Slide 50

Slide 51

Slide 52

Slide 53


Slide 55

Slide 56


Historical Overview


Historical Overview



























VSAT systems





























Iridium





Iridium






Globalstar





Teledesic


































atomic clocks


























GPS receiver









GPS Applications




















Text



Regions of Space

Satellite

EARTH STATION








Historical Overview

Slide 17

Slide 18

Slide 19

Slide 20




Slide 24

Slide 25


VSAT systems


Slide 29


Slide 31

Slide 32

Iridium

Slide 34

Globalstar

Teledesic



Slide 39

Slide 40

Slide 41


Slide 43

Slide 44

Slide 45

Slide 46

Slide 47

Slide 48

Slide 49

Slide 50

Slide 51

Slide 52

Slide 53


Slide 55

Slide 56


Historical Overview



























VSAT systems





























Iridium





Iridium






Globalstar





Teledesic


































atomic clocks


























GPS receiver









GPS Applications




















Text



Regions of Space

Satellite

EARTH STATION








Historical Overview

Slide 17

Slide 18

Slide 19

Slide 20




Slide 24

Slide 25


VSAT systems


Slide 29


Slide 31

Slide 32

Iridium

Slide 34

Globalstar

Teledesic



Slide 39

Slide 40

Slide 41


Slide 43

Slide 44

Slide 45

Slide 46

Slide 47

Slide 48

Slide 49

Slide 50

Slide 51

Slide 52

Slide 53


Slide 55

Slide 56



























VSAT systems





























Iridium





Iridium






Globalstar





Teledesic


































atomic clocks


























GPS receiver









GPS Applications




















Text



Regions of Space

Satellite

EARTH STATION








Historical Overview

Slide 17

Slide 18

Slide 19

Slide 20




Slide 24

Slide 25


VSAT systems


Slide 29


Slide 31

Slide 32

Iridium

Slide 34

Globalstar

Teledesic



Slide 39

Slide 40

Slide 41


Slide 43

Slide 44

Slide 45

Slide 46

Slide 47

Slide 48

Slide 49

Slide 50

Slide 51

Slide 52

Slide 53


Slide 55

Slide 56

























Iridium





Iridium






Globalstar





Teledesic


































atomic clocks


























GPS receiver









GPS Applications




















Text



Regions of Space

Satellite

EARTH STATION








Historical Overview

Slide 17

Slide 18

Slide 19

Slide 20




Slide 24

Slide 25


VSAT systems


Slide 29


Slide 31

Slide 32

Iridium

Slide 34

Globalstar

Teledesic



Slide 39

Slide 40

Slide 41


Slide 43

Slide 44

Slide 45

Slide 46

Slide 47

Slide 48

Slide 49

Slide 50

Slide 51

Slide 52

Slide 53


Slide 55

Slide 56

Iridium






Globalstar





Teledesic


































atomic clocks


























GPS receiver









GPS Applications




















Text



Regions of Space

Satellite

EARTH STATION








Historical Overview

Slide 17

Slide 18

Slide 19

Slide 20




Slide 24

Slide 25


VSAT systems


Slide 29


Slide 31

Slide 32

Iridium

Slide 34

Globalstar

Teledesic



Slide 39

Slide 40

Slide 41


Slide 43

Slide 44

Slide 45

Slide 46

Slide 47

Slide 48

Slide 49

Slide 50

Slide 51

Slide 52

Slide 53


Slide 55

Slide 56

Globalstar





Teledesic


































atomic clocks


























GPS receiver









GPS Applications




















Text



Regions of Space

Satellite

EARTH STATION








Historical Overview

Slide 17

Slide 18

Slide 19

Slide 20




Slide 24

Slide 25


VSAT systems


Slide 29


Slide 31

Slide 32

Iridium

Slide 34

Globalstar

Teledesic



Slide 39

Slide 40

Slide 41


Slide 43

Slide 44

Slide 45

Slide 46

Slide 47

Slide 48

Slide 49

Slide 50

Slide 51

Slide 52

Slide 53


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Teledesic


































atomic clocks


























GPS receiver









GPS Applications




















Text



Regions of Space

Satellite

EARTH STATION








Historical Overview

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VSAT systems


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Iridium

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Globalstar

Teledesic



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atomic clocks


























GPS receiver









GPS Applications




















Text



Regions of Space

Satellite

EARTH STATION








Historical Overview

Slide 17

Slide 18

Slide 19

Slide 20




Slide 24

Slide 25


VSAT systems


Slide 29


Slide 31

Slide 32

Iridium

Slide 34

Globalstar

Teledesic



Slide 39

Slide 40

Slide 41


Slide 43

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Slide 47

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Slide 50

Slide 51

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Slide 56
























GPS receiver









GPS Applications




















Text



Regions of Space

Satellite

EARTH STATION








Historical Overview

Slide 17

Slide 18

Slide 19

Slide 20




Slide 24

Slide 25


VSAT systems


Slide 29


Slide 31

Slide 32

Iridium

Slide 34

Globalstar

Teledesic



Slide 39

Slide 40

Slide 41


Slide 43

Slide 44

Slide 45

Slide 46

Slide 47

Slide 48

Slide 49

Slide 50

Slide 51

Slide 52

Slide 53


Slide 55

Slide 56









GPS Applications




















Text



Regions of Space

Satellite

EARTH STATION








Historical Overview

Slide 17

Slide 18

Slide 19

Slide 20




Slide 24

Slide 25


VSAT systems


Slide 29


Slide 31

Slide 32

Iridium

Slide 34

Globalstar

Teledesic



Slide 39

Slide 40

Slide 41


Slide 43

Slide 44

Slide 45

Slide 46

Slide 47

Slide 48

Slide 49

Slide 50

Slide 51

Slide 52

Slide 53


Slide 55

Slide 56
















Text



Regions of Space

Satellite

EARTH STATION








Historical Overview

Slide 17

Slide 18

Slide 19

Slide 20




Slide 24

Slide 25


VSAT systems


Slide 29


Slide 31

Slide 32

Iridium

Slide 34

Globalstar

Teledesic



Slide 39

Slide 40

Slide 41


Slide 43

Slide 44

Slide 45

Slide 46

Slide 47

Slide 48

Slide 49

Slide 50

Slide 51

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Slide 56

satellite communications

Documents

satellite system

revolving satellite

satellite communicationlecture

satellite bandwidth

satellite transponder

single satellite

transmitting earth station

receiving earth station