Satellite Communication

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Presentation Transcript

Satellite Communications : 

Satellite Communications COE 341 Term Paper

Groupe Members : 

Groupe Members Aref Mohammad Al-Amri Ahmad Abdulrahman Al-Gahtani Ahmad Abdullah Al-Aloula

Topics of Presentation : 

Topics of Presentation Applications Intro Lunching How itworks Frequency Bands Satellites

What are Communication Satellites? : 

What are Communication Satellites? A satellite is an object that orbits another large object like planet. A communication satellite is a staion in space that is used for telecommuncation, radio and television signals. The first satellite with radio transmitter was in 1957.

Geostationary orbits : 

Geostationary orbits What are them? Geostationary orbits is fixed position to an earth-based observer. When was the first use? The first truly geostationary sateliite was the SYNCOM3 in 1964. Why they are important in communications? - The antennas in the ground don’t need equipment to track the satellite. - Lower cost & complixity. Disadvantages? - Not always suitable for providing services at high latitudes. - Molniya satellite was introduced as a solution.

Lunching Satellites : 

Lunching Satellites How does a satellite stay in it’s orbit?

Frequency Bands : 

Frequency Bands Three common bands: C-Band. KU-Band. KA-Band. Most common are C-Band & KU-Band. C-Band occupy 4 to 8 GHz frequency:- Low frequency.- Large antenna (2-3 meters). KU-Band occupy 11 to 17 GHz:- Large frequency.- Small antenna (18-inches!)

How Does a Satellite Work? : 

How Does a Satellite Work? Consider the light bulb example:

Applications : 

Applications Telephony - Fixed points< earth station> Satellite> earth station> fixed points. Televesion & Radio - e.g. Direct broadcast satellite (DBS) & Fixed service satellite (FFS). Mobile satellite technology - Special antenna called mobile satellite antenna. - No matter where or how this antenna is mounted on.

Applications : 

Applications Amateur radio - Access to OSCAR satellite. - Low earth orbits. Internet - High Speed. - Useful for far away places. Military - Uses geostationary satellites. - Example: The Defense Satellite Communications System (DSCS).

Disadvantages : 

Disadvantages The antenna noise due to energy - Unwanted radiation sources (stars – galaxies - …etc). - Worsen S/N ratio. Atmosphere behaves as a resistive medium - Supplies noise power to the antenna. Meteors - Have to be programmed to avoid any rock or any harmful thing. - Rules of orbits. Expensive - only for governments or large organizations.

In Conclusion : 

In Conclusion Satellites remain the best utilization used for communications due to their speed and other advantages mentioned in this presentation. Thanks for Listening