Satellite Communication

Satellites

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.


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 favourite movies or TV shows would have been impossible without this. A communication satellite is a mock or artificial satellite which 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 each side of the earth is secured 

  • User can control the system 


Satellite Communication − Disadvantages 

Satellite correspondence has the accompanying disadvantages – 

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

  • Congestion of frequencies 

  • 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. 

  • Eccentricity (e) − It is the parameter that characterizes the distinction looking like the ellipse as opposed to that of a circle. 

  • Semi-Significant Pivot (a) − It is the longest distance across drawn joining the two foci along the middle, which contacts both the apogees (farthest purposes of an oval from the inside). 

  • Semi-Minor Axis (b) − It is the most limited distance drawn through the middle which contacts both the perigees (briefest purposes of an oval from the inside). 

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 time periods, the area covered by the satellite is equivalent with respect 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 these 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 in a direct way, towards itself is called centripetal power. 

  • Centrifugal Power − The power that will in general push an item moving in a direct way, 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.

FAQ (Frequently Asked Questions)

1. How Does Satellite Communication Work?

The principle segments of a satellite comprise the correspondence’s framework, which incorporates the receiving wires and transponders that get and retransmit signals, the force framework, which incorporates the solar panels that give power, and the drive framework, which incorporates the rockets that move the satellite. A satellite needs its own propulsion framework to get itself to the correct orbital area and to make infrequent revisions to that position. A satellite in the geostationary orbit can go astray up to a degree consistently from north to south or east to west of its area in light of the gravitational draw of the Moon and Sun. A satellite has engines that are terminated every so often to make changes in its position. The upkeep of a satellite's orbital position is classified as "station keeping," and the corrections made by utilizing the satellite's thrusters are designated as "attitude control."

2. What Is The Structure Of Satellite Communication?

Communication Satellites are normally made out of the accompanying subsystems: 

  • Communication Payload, typically made out of transponders, receiving wire, and switching frameworks 

  • Engines used to carry the satellite to its ideal orbit. 

  • Station Keeping Tracking and adjustment subsystem used to keep the satellite in the correct orbit, with its antenna apparatuses pointed the correct way, and its capacity framework pointed towards the sun 

  • Power subsystem used to control the Satellite frameworks, usually made out of sun-based cells, and batteries that keep up power during sunlight based overshadowing or solar eclipse

  • Command and Control subsystem, which keeps up correspondences with ground control stations. The ground control earth stations screen the satellite execution and control its usefulness during different periods of its life-cycle. 

  • The data transmission accessible from a satellite relies on the number of transponders given by the satellite. Each assistance (TV, Voice, Internet, radio) requires an alternate measure of data transfer capacity for transmission. This is normally known as connection planning and a system test system can be utilized to show up at the specific worth.