Geostationary satellites orbit Earth at an altitude of about 35,786 km, which allows them to remain fixed over the same location on Earth. This makes them useful for weather observation and communication services, as ground-based antennas do not need to track the satellite's movement. While geostationary satellites provide continuous coverage for about 40% of Earth's surface, their high orbit results in longer signal delays compared to lower-altitude satellites. Around 300 geostationary satellites currently operate around the world.

1. Geostationary Satellites and
their Orbits
Mohammed KareemMohammed Kareem

2. Satellite Frequency Bands andSatellite Frequency Bands and
Antennas (Dishes)Antennas (Dishes)
 The size of Satellite Dishes (antennas) are related toThe size of Satellite Dishes (antennas) are related to
the transmission frequency.the transmission frequency.
 There is aThere is a inverse relationshipinverse relationship between frequencybetween frequency
and wavelength.and wavelength.
 As wavelength increases (and frequency decreases),As wavelength increases (and frequency decreases),
larger antennas (satellite dishes) are necessary tolarger antennas (satellite dishes) are necessary to
gather the signal.gather the signal.

3. Satellite Frequency Bands andSatellite Frequency Bands and
Antennas (Dishes)Antennas (Dishes)
C-BandC-Band Ku-BandKu-Band
 Most commonly used bands:Most commonly used bands: C-bandC-band (4 to 8 GHz)(4 to 8 GHz) , Ku-, Ku-
bandband (11 to 17 GHz) , and Ka-band (20 to 30 GHz ).(11 to 17 GHz) , and Ka-band (20 to 30 GHz ).

4. CLASSIFICATIONCLASSIFICATION
1- LEO (LOWER EARTH ORBIT)
2- MEO (MEDIUM EARTH ORBIT)
3- GEO (GEOSTATIONARY ORBIT)

5. ORBITAL ALTITUDEORBITAL ALTITUDE
1- LEO 500-2,000KM1- LEO 500-2,000KM Above the earth.Above the earth.
2- MEO 8,000-20,000KM2- MEO 8,000-20,000KM Above the earth.Above the earth.
3- GEO 35,786KM3- GEO 35,786KM Above the earth.Above the earth.

6. GEOSTATIONARY SATELLITE
The geostationary satellite, a special case of
geosynchronous satellite has a geostationary orbit – a
circular geosynchronous orbit directly above the Earth's
equator
Geostationary satellites have the special property of
remaining permanently fixed in exactly the same position
in the sky, meaning that ground-based antennas do not
need to track them but can remain fixed in one direction.

7. Geosynchronous-Earth-Orbit (GEO)Geosynchronous-Earth-Orbit (GEO)

Orbit is synchronous withOrbit is synchronous with
the earths rotation.the earths rotation.

From the ground theFrom the ground the
satellite appears fixed.satellite appears fixed.

Altitude is about 23,000Altitude is about 23,000
miles.miles.

Coverage to 40% ofCoverage to 40% of
planet per satellite.planet per satellite.

8. GEO ORBIT DIAGRAMGEO ORBIT DIAGRAM

9. Basics of GEOsBasics of GEOs

Geostationary satellites are commonly used forGeostationary satellites are commonly used for
communications and weather-observation.communications and weather-observation.

The typical service life expectancy of a geostationaryThe typical service life expectancy of a geostationary
satellite is 10-15 years.satellite is 10-15 years.

Because geostationary satellites circle the earth at theBecause geostationary satellites circle the earth at the
equator, they are not able to provide coverage at theequator, they are not able to provide coverage at the
Northernmost and Southernmost latitudes.Northernmost and Southernmost latitudes.

10. GEOs and WeatherGEOs and Weather

The altitude is chosen soThe altitude is chosen so
that it takes the satellitethat it takes the satellite
24 hours to orbit the Earth24 hours to orbit the Earth
once, which is also theonce, which is also the
rotation rate of the Earth.rotation rate of the Earth.

This produces the cloudThis produces the cloud
animations you see onanimations you see on
TV.TV.

Can take imagesCan take images
approximately everyapproximately every
minute.minute.

11. Facts about GEOsFacts about GEOs
 Instruments on GEOs are designed to last 3-9 years.Instruments on GEOs are designed to last 3-9 years.
 Measurements that are taken are in the form of electricalMeasurements that are taken are in the form of electrical
voltages that are digitized, and then transmitted tovoltages that are digitized, and then transmitted to
receiving stations on the ground.receiving stations on the ground.
 Instruments usually have:Instruments usually have:
 Small telescope or antenna.Small telescope or antenna.
 A scanning mechanism.A scanning mechanism.
 One or more detectors that detect either visible,One or more detectors that detect either visible,
infrared, or microwave radiation.infrared, or microwave radiation.

12. GEOsGEOs

Satellites areSatellites are
positioned every 4-8positioned every 4-8
degrees.degrees.

Aproximately 300 GEOAproximately 300 GEO
satellites are in orbit.satellites are in orbit.

13. Pros and Cons of GEOsPros and Cons of GEOs
 Advantages:Advantages:
 Weather images canWeather images can
be displayed.be displayed.
 Television broadcastsTelevision broadcasts
are uninterrupted.are uninterrupted.
 Used to track majorUsed to track major
developments such asdevelopments such as
hurricanes 24 hours ahurricanes 24 hours a
day.day.
 Disadvantages:Disadvantages:
 It takes longer for theIt takes longer for the
signal to get to earthsignal to get to earth
and back to satellite.and back to satellite.
 Increased difficulty ofIncreased difficulty of
telephonetelephone
conversations.conversations.
 GEOs are notGEOs are not
positioned in thepositioned in the
farthest northern andfarthest northern and
southern orbits.southern orbits.

14. Sep 4, 2017Sep 4, 2017 1414 Satellite CommunicationsSatellite Communications
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