[Physics Class Notes] on Satellite Communication Pdf for Exam

A satellite is a body that passes around some other body in a mathematically foreseeable path which is often called an Orbit. A communication satellite is nothing but a microwave repeater station in space that plays a significant role in telecommunications, radio, and television along with internet applications.

Here’s some satellite history for you: the Soviet Union was the first country to launch an artificial satellite into space. The satellite was named Sputnik and launched on 4th October 1957. Sergei Korolev was its chief designer.

The satellite is structured such that it can power itself. The solar panels on the satellite generate solar power to run the satellite. The power is supplied to the propulsion system which has rockets to propel the satellite forward.

What is Satellite Communication?

Satellite communication is the technique of conveying data from one place to another using a communication satellite in the earth’s orbit. Watching your favorite movies or TV shows would have been impossible without this. A communication satellite is a mock or artificial satellite that is responsible for transmitting a signal using a transponder by creating a channel between the transmitter and the receiver which are located in two entirely different locations on earth. 

Now, let us have a look at the advantages, disadvantages, and applications of satellite communications.

Satellite Communication – Advantages

There are numerous Advantages of satellite correspondences, for example, − 

• Flexibility 

• Ease in putting in new circuits 

• Distances are effortlessly taken care of and expense doesn’t make a difference 

• Broadcasting conceivable outcomes 

• Each and  every side of the earth is secured 

• Users can control the system 

• Energy is conserved since satellites use solar power

Satellite Communication − Disadvantages 

Satellite correspondence has the accompanying disadvantages – 

• The introductory costs, for example, the segment and installation costs are excessively high.

• Congestion of frequencies. This can cause a disruption of the communication services

• Interference and proliferation 

Satellite Communication − Applications 

Satellite correspondence discovers its applications in the accompanying zones – 

• In Radio telecom. 

• In TV broadcasting, for example, DTH. 

• In Internet applications, for example, giving Internet connection for transferring data, GPS applications, Internet surfing, and so on. 

• For voice correspondences. 

• For innovative work, in numerous regions. 

• In military applications and routes. 

The direction of the satellite in its orbit relies on the three laws called Kepler’s laws.

Kepler’s Laws

Johannes Kepler (1571-1630) the galactic researcher, gave 3 progressive laws, in regards to the movement of satellites. The way pursued by a satellite around its essential (the earth) is an elliptical path. An eclipse has two foci – F1 and F2, the earth being one of them. 

Kepler’s First Law 

Kepler’s first law expresses that, “each planet rotates around the sun in a circular circle, with the sun as one of its foci.” As such, a satellite moves in a curved path with the earth as one of its foci. 

The semi-major axis of the ellipse is meant as ‘a’ and a semi-minor axis is indicated as b. 

 

These are very much portrayed in the accompanying figure.

(Image to be added soon)

Kepler’s Second Law 

Kepler’s second law expresses that, “For equivalent periods, the area covered by the satellite is equivalent to the focal point of the earth.” It very well may be comprehended by investigating the accompanying figure. 

(Image to be added soon)

Assume that the satellite covers p1 and p2 separations, in a similar time stretch, at that point the regions B1 and B2 shrouded in the two examples respectively, are equivalent. 

Kepler’s Third Law 

Kepler’s third law expresses that, “The square of the intermittent time of the orbit is corresponding to the cube of the mean separation between the two bodies.” The orbital working of satellites is determined with the assistance of Kepler’s laws. 

Alongside these, there is something essential that must be noted. A satellite, when it rotates around the earth, experiences a pulling force from the earth which is the gravitational force. Likewise, it encounters some pulling force from the sun and the moon. Subsequently, there are two forces following up on it. They are − 

• Centripetal Power − The power that will in general draw an item moving directly towards itself is called centripetal power. 

• Centrifugal Power − The power that will in general push an item moving directly away from its position is called radiating power. 

In this way, a satellite needs to adjust these two powers to keep itself in its circle.

Types of Satellites and Applications

• Communications Satellite.

• Remote Sensing Satellite.

• Navigation Satellite.

• Geocentric Orbit type satellites – LEO, MEO, HEO.

• Global Positioning System (GPS)

• Geostationary Satellites (GEOs)

• Drone Satellite.

• Ground Satellite.