Topics discussed on this presentation slide: Satellite Orbit Footprint Satellite Categories GPS Global star TELEDICS

1. Welcome
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2. Topics
Satellite
Orbit
Footprint
Satellite Categories
GPS
Global star
TELEDICS
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3. Satellite Network
 Combination of nodes
 Like a cellular network
 Provide communication
 Microwave repeater station
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4. Orbits
An orbit is a regular, repeating path that one object in space takes
around another one.
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6. Satellite Orbits
An artificial satellite needs to have an orbit, the path in which it travels
around the Earth.
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8. Footprint
• The area of the Earth covered by the microwave radiation from a
satellite dish (transponder) is called the satellites footprint.
• The size of the footprint depends on the location of the satellite in its
orbit, the shape and size of beam produced by its transponder and
the distance from the earth.
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10. Categories of Satellite
Based on location of the orbits:
• Geostationary Earth Orbit (GEO)
• Low Earth Orbit (LEO)
• Medium Earth Orbit (MEO)
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11. Geostationary Earth Orbit (GEO)
 These satellites are in orbit 35,786 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.
 One GEO satellite cannot cover the whole earth. It takes minimum
of three satellites equidistant from each other.
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13. Geostationary Earth Orbit (GEO)
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14. Medium Earth Orbit (MEO)
 A MEO satellite is in orbit somewhere between 5,000 km and 15,000
km above the earth’s surface.
 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.
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16. Low Earth Orbit (LEO)
• LEO satellites are much closer to the earth than GEO satellites,
ranging from 500 to 2000 km above the surface.
• Rotation period of 90 to 120 minutes, with speed 20,000 to 25,000
km/h.
• LEO satellites don’t stay in fixed position relative to the surface, and
are only visible for 15 to 20 minutes each pass.
• A network of LEO satellites is necessary for LEO satellites to be
useful.
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18. GPS – Global Positioning System
Constructed and operated by US Department of Defense.
 There are 24 satellites in six orbits.
 Used for land, sea and air navigation to provide time and locations
for vehicles and ships.
 The satellites in each orbits are designed in such a way, at a time
minimum four satellites are visible from any point on the Earth.
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20. Orbits for GPS Satellite System
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21. Global Star
 It has 48 satellites in 6 LEO orbits.
 Each have altitude of 1400 km.
 The ground station can create more powerful signals.
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22. TELEDESIC
 It provides fiber-optic like (broadband channels, low error rate, and
low delay) communication.
 It has 288 satellites in 12 LEO polar orbits.
 Each have altitude of 1350 km.
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23. Thank you
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