SATELLITE COMMUNICATION

What is an artificial satelitte?

an artificial body placed in orbit around the earth or moon or another planet in order to collect information or for communication.

man-made equipment that orbits around the earth or the moon.

It acts as a relaying station for wireless communication for a long distance transmission.

Background Sputnik - 1st artificial satelitte launched

by the Soviet union It pioneered the space exploration 6,600 satellites have been launched latest estimates are that 3,600 remain in

orbit About 1,000 are operational Philippines launched its first satellite

Agila-2

What are satellite used for?

Television Telephones Weather Space Science

Types of Satellite orbit Polar – it orbits the earth near the north

pole to the south pole.

Types of Satellite orbit Sun Synchronous - orbits allows a

satellite to pass over a section of the Earth at the same time of day.

Types of Satellite orbit Geosynchronous Orbits - orbits the Earth

at the same rate as the Earth spins

How Satellites Stay in Orbit? It must travel faster in order to maintain

orbit. V=(GM/R)^1/2 The greater the altitude, the less velocity

is needed to maintain the orbit. Velocity and gravitational pull between

the satellite and the planet it orbit.

What is the importance of Sat. communication?

It is used as relay station for wireless communication for a long distance transmission.

Useful in telecommunication at remote areas.

Lesser noise generated than using multiple earth antenna relay station.

Able to relay data against the curvature of the earth, which limits ground earth station capabilities to transmit data for long distance transmission.

Digital signal processing in communications satellite

Satellite on-board digital signal processing (DSP) offers the potential for significantly improved performance in certain satellite communications system scenarios in terms of system capacity and link quality.

Digital signal processing in communications satellite

On-board DSP functions include digital beamforming, frequency multiplexing and demultiplexing, interference suppression, signal level control and, in a regenerative system, modems. DSP in satellite communications satellite, focusing on the system advantages, some basic algorithms, and application specific IC implementation issues.

Digital signal processing in communications satellite

As a specific illustrative example an advanced land mobile system is described which features digital beamforming and associated digital signal processing to achieve significant gains in power efficiency (and hence capacity), frequency reuse and flexibility to response to changing traffic scenarios

Digital signal processing in communications satellite

In summary, satellite uses DSP in forms of multiplexing and demultiplexing systems.

The satellite receives multiple data from the earth to be transmitted to a different designated location on earth. Some data arrives at same time. Some uses the same frequency.

This is why MUX and DEMUX systems are needed.

Satellites uses different MUX and DEMUX system. Examples of this systems are CDMA, FDMA, and

SPADE DAMA.