Page 27 - SATELLITE AND RADAR COMMUNICATION SYSTEM

Footprint Categories

 The Spot and Zonal Beams:
– Concentrated power to very small geographical areas

– Have high EIRPs
– Blanket less than 10% of earth’s surface

 Hemispherical Beam
– Blanket 20% of Earth’s surface
– Have EIRP that are 3dB lower than spot beams

 Earth (Global)

– Beam width of approximately 17˚
– Coverage of up to 42% of earth’s surface

– Power levels are considerably low

Orbit inclination and latitude coverage

 The north and south latitudes of the terrestrial segment covered by the
satellites ground track depend on the satellite orbit inclination.

 There are three types of the inclination satellite orbits:

Figure 1.15: Inclination satellite orbit

 Equatorial orbit: The orbit which plane coincide with the equator of the

earth is known as equatorial orbit. Their inclination angle is 0°
 Inclined orbit: The orbit which is neither equatorial nor polar is known
as inclined orbit. Their inclination angle lies between 0 to 90°

 Polar orbit: The orbit which plane coincide with any polar axis of the
earth (a line passing the reference points of the north and south poles)
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is known as polar orbit. Their inclination angle is 90°

Introduction to Satellite Communication System