Satellite Internet is the ability to transmit and receive data from a relatively small satellite dish on Earth and communicate with an orbiting geostationary satellite 22,300 miles above Earth's equator.
LEO
MEO
GEO
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Satellite Network
1. Dr. Ambedkar Institute of Technology
(An Autonomous Institution, Affiliated to V.T.U)
Bangalore-560056
SATELLITE NETWORKS
A Seminar by,
PRIYANKA P B
1TU17LDN04
1
3. SATELLITE AND ORBITS
An orbit is the path that a satellite follows as it revolves around
the earth. Basically , there are three main categories of orbits they
are
Low earth orbit (LEO)
Medium earth orbit (MEO)
Geosynchronous earth orbit (GEO)
4. Low Earth Orbit Satellites
LEO is 500-2000 km above the earth.
LEO orbits are much closer to the earth requiring satellites to travel at a very hifh speed to avid
being pulled out of orbit by earths gravity.
At LEO , a satellite can circle the earth in approx 1.5h
Depending on the frequency bands used by different satellites, these can be broadly categorized
into three types
The little LEOs operating under 1 GHz and used for low data rate communication.
The big LEOs operating in the range 1 to 3 GHz and the Broadband and the broadband LEOs
provide communication capabilities similar to optical networks.
5. Medium Earth Orbit Satellites
MEO is the 8000-20,000 km above the earth surface.
MEOs are primarly reserved for communication satellite that cover the north and south pole.
MEOs are placed in an elliptical orbit.
One important example of the MEO satellites is the Global Positioning System (GPS).
It comprises a network of 24 satellites at an altitude of 20,000 Km (Period 12 Hrs) and an
inclination of 55°.
Although it was originally intended for military applications and deployed by the Department
of Defense .It allows land, sea and airborne users to measure their position, velocity and time.
It works in any weather conditions, 24 hrs a day.
6. Geosynchronous earth orbit Satellites
GEO satellite orbit at the height of 22,282 miles above the equator ;the satellite travels in the same
direction and at the speed as the earth’s rotation on its axis taking 24h to complete full trip around
the globe.
A single geostationary satellite can view approx. one third of the earths surface.
Three satellites placed at the proper longitude can provide full global coverage in GEO system.
GEO has its major advantage today because of following reasons:
One satellite can cover almost one third of the earths surface offering a reach far more extensive
than that of any terrestrial network.
GEO remains stationary over a small orbital location.
GEO are proven , reliable and secure.
7. SALIENT FEATURES
Communication from earth station to satellite is called uplink channel whereas
communication from satellite to earth station is called downlink channel. Some
of the features of satellite network are:
Coverage
Speed
Security
Service types
Usage
Repeater
Packet switched
Frequency band
10. ADVANTAGES OF SATELLITE COMMUNICATION
Provide global coverage to remote areas.
Alternate mode of communication in military applications and
disaster recovery scenario.
Support multipoint communication
Ease of network expansion and flexibility of station organization
11. DISADVANTAGES
Bursts error condition
Higher bit rate
Long delay and anormous cost associated with user terminal ,
earth station and satellite as a whole.
Limited transmission power of both the ground terminals and the
satellite.
12. REFERENCES
WIRELESS AND MOBILE NETWORKS BY
DR.SUNILKUMAR S MANVI.
BROADCAST COMMUNICATION NETWORKS VERSION 2
CSE IIT , KHARAGPUR.
SATELLITE SYSTEMS BY DR.DHARMA P AGARWAL.