Satellite Communication: Working, Applications and Advantages

Satellite communications is a part of the telecommunications system which uses artificial satellites to transport information from one place to another place on Earth. Carrier signals used in satellite communication are Electromagnetic waves. These signals carry information such as audio, video, or any other data between ground and space and vice-versa.

• A communications satellite is an artificial satellite that creates a communication link between a source transmitter and a receiver at different locations on Earth.
• Satellite communication consists of mainly two segments. These are the Space segment and the Earth segment.
• The Space segment is Satellite itself.
• The main functions of the Earth segment are the transmission of a signal to the satellite and the reception of a signal from the satellite.
• Satellite communication plays a pivotal role in the transmission of radio waves, telecommunications, television waves, and internet facilities.

Key Terms: Satellites, Satellite communication, transmitting signals, transponders, artificial satellites, radio waves, telecommunications, television waves, telecommunications system

Also Read: Space travel equipment

Satellites 

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A satellite is an object (moon, planet, or machine) in space that orbits or circles around a bigger object. For example, Earth is a satellite of the sun because it orbits around it. Similarly, the moon is a satellite of Earth because it orbits around it. There are two kinds of satellites:

• Natural Satellites: A natural satellite is an astronomical body that orbits a planet, dwarf planet, or small Solar System body. Such as the moon orbiting the Earth, 
• Artificial Satellites: A artificial satellite is an object that is intentionally placed into orbit in outer space. Artificial Satellites have a variety of uses, such as weather forecasting, communication relay, broadcasting, navigation (GPS), and Earth observation. The world’s first artificial satellite to be launched into the Earth’s orbit was Sputnik 1 which lifted off on Oct. 4, 1957.

Types of Artificial Satellites

There are two types of artificial satellites that help in the transmission of signals and are known as Passive Satellite and Active Satellite.

Passive Satellites

A passive satellite is known to be the kind of satellite that is capable of reflecting the signal from one earth station to another, despite the need for any retransmission. Passive Satellites were amongst the earliest to surface, but with time elapsing forward, active satellites have subjugated the market.

Passive satellites

Active Satellites

Unlike passive satellites, active satellites help amplify the signals that are transmitted prior to retransmitting them back to ground stations. It also ensures the provision of brilliant signal strength.  

Active Satellites

Read more: Need for modulation

Satellite Communications

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Satellite communication is a process that allows the transmission of information from one specific place to another by means of a communication satellite that orbits around the planet.

• Mainly, a communication satellite is an artificial satellite that is responsible to convey useful information, like transmission of military applications, through a transponder, especially by crafting a channel source between the transmitter and the receiver stationed at two or more different locations on Earth.
• There are more than 2000 artificial satellites that are coursing around the Earth and transmitting important signals to us.
• For instance, radio, televisions, internet applications, and military applications use modern-day satellite facilities to propagate useful information across the Earth.

Also Read: what is Internet?

Need for Satellite Communication

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Earlier, for communication up to some distance, there are two kinds of propagation were used:

• Ground Wave Propagation: suitable for frequencies up to 30MHz
• Sky Wave Propagation: suitable for frequencies up to 30-40MHz

But the communication distance between two stations is limited to 1500 km in these types of propagations. Satellite communication overcomes this limitation. Satellites are located at a certain height above the earth, so communication becomes easy between any two earth stations.

Also Read: Difference Between AM and FM

Workings of Satellite Communication

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Communication satellites facilitate ricochet signals like radio waves, internet data, and television from one remote location to another. 

There are three imperative steps to attend that can further help elaborate the process involved in the workings of Satellite Communications are:

• Uplink: The transmission of the signal from the first earth station to the satellite through a channel is called an uplink. The frequency at which, the first earth station is communicating with the satellite is called Uplink Frequency.
• Transponders: Transponders such as radio receivers, amplifiers, and transmitters boost the incoming signal converts this signal into another frequency, and sends it down to the second earth station.
• Downlink: The transmission of the signal from the satellite to the receiver station through a channel is called a downlink.

The Block Diagram of Satellite Communications is shown below:

Block Diagram of Satellite Communications

Also Read: Electromagnetic Spectrum

Advantages and Disadvantages of Satellite Communication

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Satellite communications have multiple advantages stated below:

1. It is flexible. 
2. Can easily apply new circuits.
3. Until today, there has been no issue in transmitting signals all over the planet
4. The expense it imposes does not quite make any difference.
5. The user can easily access every domain of the network and can navigate it easily.

Along with advantages satellite communication does have certain disadvantages as well which are listed below:

1. The primary expenditure, such as the fundamental installing expenses are often outrageously costly.
2. There is a visible congestion of frequencies.
3. Interference and propagation.

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Applications of Satellite Communications Communication

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Certain applications of satellite communication are:

1. Radio Signals
2. Television
3. RFID Device
4. Disaster Management Services
5. Telephone and more.

Some communication satellites of India along with their applications are given below:

• GSAT-24: Launched on June 22, 2022, for Communication purposes.
• GSAT-30:  Launched on Jan 17, 2020, for Communication purposes.
• GSAT-31: Launched on Feb 06, 2020, for Communication purposes.
• GSAT-11: Launched on Dec 05, 2018, for Communication purposes.
• GSAT-15: Launched on Nov 11, 2015, for Communication purposes.
• GSAT-7: Launched on Aug 30, 2013, for Communication purposes.
• GSAT-10: Launched on Sep 29, 2012, for Communication purposes.
• INSAT-3A: Launched on Apr 10, 2003, for Communication purposes.
• KALPANA-1: Launched on Sep 12, 2002, for Communication purposes.

Also Read: Pulse Amplitude Modulation

Satellite Communication Services

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Satellite Communication services can be bifurcated into two main segments, namely, One-way satellite communication and two-way satellite communication.

One-Way Satellite Communication

The kind of communication seen in One-way satellite communication is that it generally takes occurs between either one or multiple earth stations with the assistance of a satellite. One of the major examples is internet services provided to users by means of broadcasting satellites.

One-Way Satellite Communication

Two-Way Satellite Communication: 

A two-way satellite communication is capable of sending data from a remote site to a hub by means of a satellite facility. Further, the hub is seen to process the data onto an online server. For example, two-way satellite communications occur when signals are processed from one Earth location to another.

Two-Way Satellite Communication

Check out: What is optical fiber

Things to Remember

1. Satellites are microwave repeater stations that conventionally orbit around space. Its role is considered imperative in the transmission of radio waves, telecommunications, television waves, and internet services.
2. Satellite communication allows the transmission of data from one location to another by means of a satellite that orbits around the planet. 
3. There are three significant stages to attend that can help lay out the process involved in the workings of Satellite Communications, namely, Uplink, Transponders, and Downlink.
4. Satellite communications are utilized in radio telecoms, DTH (television broadcast), telephone signals, and RFID devices.
5. Satellite communications can be dissected into two segments, one-way satellite communications, and two-way satellite communications.

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