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    Satcom

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    Vikas Ps
    This document discusses different types of satellite systems based on orbital height. It describes Low Earth Orbit (LEO) systems between 500-1500km with visibility periods of 15-20 minutes, requiring many satellites for coverage. Medium Earth Orbit (MEO) systems operate between 8000-18000km with longer 2-8 hour visibility. Geostationary orbits (GEO) sit at 35,863km, remaining fixed over one point of Earth, providing broad coverage but weaker signals and higher launch costs than LEO or MEO systems. The document outlines the characteristics and advantages/disadvantages of each orbital system type.

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    © All Rights Reserved
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    Satcom

    Uploaded by

    Vikas Ps
    45 views11 pages
    This document discusses different types of satellite systems based on orbital height. It describes Low Earth Orbit (LEO) systems between 500-1500km with visibility periods of 15-20 minutes, requiring many satellites for coverage. Medium Earth Orbit (MEO) systems operate between 8000-18000km with longer 2-8 hour visibility. Geostationary orbits (GEO) sit at 35,863km, remaining fixed over one point of Earth, providing broad coverage but weaker signals and higher launch costs than LEO or MEO systems. The document outlines the characteristics and advantages/disadvantages of each orbital system type.

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    satcom.pptx

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    This document discusses different types of satellite systems based on orbital height. It describes Low Earth Orbit (LEO) systems between 500-1500km with visibility periods of 15-20 minutes, requiring many satellites for coverage. Medium Earth Orbit (MEO) systems operate between 8000-18000km with longer 2-8 hour visibility. Geostationary orbits (GEO) sit at 35,863km, remaining fixed over one point of Earth, providing broad coverage but weaker signals and higher launch costs than LEO or MEO systems. The document outlines the characteristics and advantages/disadvantages of each orbital system type.

    Copyright:

    © All Rights Reserved
    Download as PPTX, PDF, TXT or read online from Scribd
    Download as pptx, pdf, or txt
    45 views11 pages

    Satcom

    Uploaded by

    Vikas Ps
    This document discusses different types of satellite systems based on orbital height. It describes Low Earth Orbit (LEO) systems between 500-1500km with visibility periods of 15-20 minutes, requiring many satellites for coverage. Medium Earth Orbit (MEO) systems operate between 8000-18000km with longer 2-8 hour visibility. Geostationary orbits (GEO) sit at 35,863km, remaining fixed over one point of Earth, providing broad coverage but weaker signals and higher launch costs than LEO or MEO systems. The document outlines the characteristics and advantages/disadvantages of each orbital system type.

    Copyright:

    © All Rights Reserved
    Download as PPTX, PDF, TXT or read online from Scribd
    Download as pptx, pdf, or txt
    of 11

    GLOBAL

    SATELLITE
    SYSTEM

    23/04/2010 1
    INTRODUCTION
    • The word satellite originated from the Latin word “Satellit”-
    meaning an attendant, one who is constantly hovering around &
    attending as a “master” or big man.

    • a satellite is simply any body that moves around another (usually


    much larger) one in a mathematically predictable path called an
    orbit.

    • Station on the earth transmits signal to satellite is called uplink,


    while from satellite to earth station is called downlink.

    • For both uplink & downlink frequency is different.

    • Satellite is generally use for communication of radio & television


    signal.

    23/04/2010 2
    TYPES OF SATELLITE SYSTEM
    • Satellite orbits are also classified based on their heights above the
    earth:
    • Lower earth orbit ( LEO)
    • Medium earth orbit (MEO)
    • Geostationary (GEO)

    •All the satellite system designs are differentiate by the type of the
    orbit in which satellite deployed.

    23/04/2010 3
    LOW EARTH ORBIT (LEO)
    • LEO systems fly about 500 to 1,500 kilometers above the Earth. A
    typical LEO satellite takes less than two hours to orbit the Earth,
    and are only visible for 15 to 20 minutes each pass.

    •Low earth orbiting satellites are less expensive to launch into


    orbit as distance from the earth is less, don't require as high signal
    strength and give less time delay.

    •A LEO satellite’s smaller area of coverage is less as compared to


    other orbital system.

    • So for local applications, a large number of satellites are needed


    if the mission requires uninterrupted connectivity.

    23/04/2010 4
    LOW EARTH ORBIT(LEO) (Cont.)
    • It is also possible to offer discontinuous coverage using a low Earth
    orbit satellite capable of storing data received while passing over one
    part of Earth and transmitting it later while passing over another
    part.

    Fig : LEO satellite system.

    23/04/2010 5
    MEDIUM EARTH ORBIT(MEO)
    •A MEO satellite is in orbit somewhere between 8,000 km and
    18,000 km above the earth’s surface.

    •MEO satellites are similar to LEO satellites in functionality.

    •MEO satellites are visible for much longer periods of time than LEO
    satellites, usually between 2 to 8 hours.

    •MEO satellites have a larger coverage area than LEO satellites,


    hence there are less number of satellite required as compared to
    LEO.

    •A MEO satellite’s distance gives it a longer time delay and weaker


    signal than a LEO satellite, but not as bad as a GEO satellite.

    23/04/2010 6
    MEDIUM EARTH ORBIT(MEO)

    MEO satellite system

    23/04/2010 7
    GEOSTATIONARY ORBIT(GEO)
    • These satellites are in orbit 35,863 km above the earth’s surface
    along the equator.

    • Objects in Geostationary orbit revolve around the earth at the same


    speed as the earth rotates. This means GEO satellites remain in the
    same position relative to the surface of earth.

    23/04/2010 8
    GEOSTATIONARY ORBIT(GEO) (Cont.)
    Advantages :

    • A GEO satellite’s distance from earth gives it a large coverage area,


    almost a fourth of the earth’s surface.

    •GEO satellites have a 24 hour view of a particular area. these factor


    make it ideal for satellite broadcast and other multipoint
    applications.

    •GEO systems are less complicated to maintain because their fixed


    location in the sky requires relatively little tracking capability in
    ground equipment.

    23/04/2010 9
    GEOSTATIONARY ORBIT(GEO) (Cont.)
    Disadvantages :

    • As compared to the previous method because launching of the


    satellite into their orbit is to expansive.

    •At large distance from the earth hence there is problem with signal
    strength which is very low, due to this large antenna is required for
    reception of the signal.

    • GEO has more distant orbit so it subject to transmission delays.

    23/04/2010 10
    References (Online)
    • http://www.compassroseintl.com

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

    • courses.missouristate.edu/HuiLiu/csc690/slides/Satellite.ppt

    23/04/2010 11

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