Satellite Network

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

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

2. INTRODUCTION TO SATELLITE NETWORK

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 T he little LEOs operating under 1 GHz and used for low data rate communication. T he 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

8. SATELLITE ARCHITECTURE SATELLITE GROUND STATIONS USERS HANDOVERS AND RE-ROUTING SATELLITE WIRELESS STANDARDS

9. APPLICATIONS Weather forecasting Navigation Astronomy Satellite phone Satellite television Satellite internet and many more

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.

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