SATELLITE COMMUNICATION Technical Seminar Report Submitted in partial fulfilment of the requirements for the award of the degree of Bachelor of Engineering in Electronics and Communication Engineering Submitted by Lachu Man Limbu 0215414 DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING COLLEGE OF SCIENCE AND TECHNOLOGY RINCHENDHING
SATELLITE COMMUNICATION
Technical Seminar Report
Submitted in partial fulfilment of the requirements for the award of
the degree of Bachelor of Engineering
in
Electronics and Communication Engineering
Submitted by
Lachu Man Limbu
0215414
DEPARTMENT OF
ELECTRONICS AND COMMUNICATION ENGINEERING
COLLEGE OF SCIENCE AND TECHNOLOGY
RINCHENDHING :: PHUENTSHOLING, BHUTAN
October 2018
i
Acknowledgement
I really feel that, this is my great opportunity to enhance my knowledge
level. In due course of doing this seminar, I was able to acquire valuable
information and had consumed huge amount to work, research and
dedication. The successful completion of my seminar is solely because of
the consistent support and guidance given to me during whole process of my
research.
Therefore I would like to thank the department of Electronics and
Communication of the college for letting us to work on the seminar.
Moreover, my hearty gratitude goes to my seminar guide Mr. Jigme Zangpo
for guiding me with the work schedules and providing with relevant
documents of seminars and also for his consistent help in the process of
doing this seminar.
I also would like to thank each and every individual who directly or
indirectly helped me in contributing to the completion of my seminar.
ii
Abstract
Satellite communication is one of the most important means of communication.
It is regarded as one of the backbones of long distance wireless communication.
Satellite communication provides broadband communication along with fiber
optic communication. These days due to advancement in technology, the
artificial earth satellites have emerged as an essential part of telecommunication
infrastructure around the globe. Besides telecommunication, the satellites are
also being used for purpose of meteorological data collection and weather
forecasting, search and rescue, global positing system, minerals and oil
exploration, maritime navigation and so on. The main purpose of
communication satellite is to relay the signal around the curve of the Earth
allowing communication to happen through wide ranges and distant points. The
electromagnetic signals that communication satellites work with, have a large
spectrum of wavelengths and frequencies. To keep these waves from interfering
with one another, international organizations have certain rules and regulations
describing which wavelength a certain company or group can use. By separating
out wavelengths, communication satellites will have minimal interference and
be able to communicate effectively.
iii
List of Abbreviations
Abbreviation Description Page
TV Television 1
GEO Geostationary Earth Orbit 3
MEO Medium Earth Orbit 4
LEO Low Earth Orbit 8
GHz Giga Hertz 11
MHz Mega Hertz 12
RF Radio Frequency 12
iv
List of Tables
Table 1: Main frequency bands used by satellite communication system (Reddy, n.d.). 11
v
List of Figures
Figure 1: Satellite Communication (University of Science and Technology of China, 2018). 2
Figure 2: General Block Diagram of the Satellite communication system (DAEnotes, 2018). 3
Figure 3: Different types of orbits for satellite communication (Hussaini, 2017). 4
Figure 4: Low earth orbit (Reddy, n.d.). 5
Figure 5: Medium earth orbit (Reddy, n.d.). 6
Figure 6: Geostationary earth orbit (Reddy, n.d.). 7
Figure 7: Working of Satellite Communication in brief. 9
Figure 8: Basic Elements of Satellite Communications System (Visahli, 2014). 10
Figure 9: Block diagram of the Transponder (Vamsiram’s Jyothi Celestia, n.d.). 12
vi
Contents
Acknowledgement i
Abstract ii
List of Abbreviations iii
List of Tables iv
List of Figures v
Contents vi
1 INTRODUCTION 1
2 SATELITE COMMUNICATION 2
2.1 Types of Satellite 3
2.1.1 Active satellite 4
2.1.2 Passive satellite 4
2.2 Different Types of Orbit 4
2.2.1 Low Earth Orbit (LEO): 500-2000 km above the earth 5
2.2.2 Medium Earth Orbit (MEO): 8,000-20,000 km above the earth 6
2.2.3 Geostationary Earth Orbit (GEO) Beyond 36,000 km above the earth 7
3 WORKING OF SATELLITE COMMUNICATION 9
3.1 Working of Uplink and Downlink 10
3.2 The Transponder 12
4 APPLICATIONS OF SATELLITE COMMUNICATION 13
4.1 Weather Forecasting 13
4.2 TV and Radio Broadcast 13
4.3 Military Satellites 13
4.4 Navigation Satellites 13
4.5 Global Telephone 14
4.6 Global Mobile Communication 14
5 ADVANTAGES AND DISADVANTAGES OF SATELLITE COMMUNICATION 15
5.1 Advantages 15
5.2 Disadvantages 15
6 CONCLUSION 16
References 17
1
1 INTRODUCTION
A satellite is a self-contained communication system with the ability to receive signals from
the Earth, amplify it and retransmit those amplified signals back with the use of transponder –
an integrated receiver and transmitter of radio signals. A satellite is an object that orbits or
revolves around another object. And if a satellite is man-made and place around the earth for
communication purpose at microwave frequency level then it is called as a satellite
communication. Most communications satellites use geosynchronous orbits or near
geostationary orbits, although some recent systems use low Earth-orbiting satellites (R.Elbert,
2008).
Communications satellites provide a technology that is complementary to that of fiber optic
submarine communication cables. But unlike fiber optic communication, satellite
communication has a propagation delay of at least 270 milliseconds, which is the time it takes
by the radio signal to travel 35,800 km from earth to a satellite and then back to earth.
Therefore satellite internet connections has an average delay of 600-800 millisecond i.e.,
about ten times more than that of a terrestrial Internet link. This delay is more of a challenge
to deployment of Virtual private networks over satellite internet connections all over the
world.
The main idea of satellite communication was first proposed by Arthur C. Clarke, based on
Herman Poto?nik's pseudonymous work from 1929. After 16 years later in the year 1945
Clarke published an article titled “Extra-terrestrial Relays” in the magazine Wireless World.
The article described the fundamentals behind the deployment of artificial satellites in
geostationary orbits for the purpose of relaying radio-wave signals. Thus Arthur C. Clarke is
often quoted as the inventor of the communications satellite.
Using satellite communication, people all over the world can share their information through
telephone, exchange e-mails or messages from anywhere in the world and have access to
Internet and receive hundreds of TV channels in their homes. Unlike fiber optic technology it
can it can be used in providing communication in difficult terrains, high mountain regions,
oceans, etc.
2
2 SATELITE COMMUNICATION
Figure 1: Satellite Communication (University of Science and Technology of China, 2018).
Satellite communication is one of the most important means of communication. It is regarded
as one of the backbones of long distance wireless communication. Satellite communication
provides broadband communication along with fiber optic communication. These days the
artificial earth satellites have emerged as an essential part of telecommunication
infrastructure around the world. Besides telecommunication, the satellites are also being used
for purpose of meteorological data collection and weather forecasting, search and rescue,
global positing system, minerals and oil exploration, maritime navigation and so on.
All the communication system must have a medium for operation. Likewise satellite
communication system also uses a satellite as a repeater between two points that exchange
information. So probably here the medium will be air and information is being passed as
electromagnetic waves. Satellite communication is important where installation of cable is
difficult and as a whole from the cost analysis point of view satellite communication is more
effective than using cables and optical fibre. Therefore satellite communication has emerged
fruitful in wideband communication systems like TV Broadcasting, Defence, Weather
forecasting, space navigation and telemetry (Roddy, 1995).
3
However general block diagram of the Satellite communication consists of the following
components.
Figure 2: General Block Diagram of the Satellite communication system (DAEnotes, 2018).
The ground station also known as earth segment consists of a base band processor, an up-
converter, high Powered amplifier and a parabolic dish antenna and are mainly used to
transmit the terrestrial data to an orbiting satellite. In the case of downlink, the ultimate
reverse operation happens whereby the up-linked signals are recaptured through parabolic
antenna.
The transponder comprises of a receiving antenna that receives signals from the ground
station, a broad band receiver, an input multiplexer and a frequency converter that is used to
reroute the received signals through a high powered amplifier for downlink. The key function
of satellite is to reflect electromagnetic signals. Like in case of a telecom satellite, the
primary role of the satellite is to pick up signals from a ground station that might be located at
certain distant.
2.1 Types of Satellite
The satellite can be classified into two categories:
Uplink signal 5.9 t0 6.4
GHz
2.2 GHz local
Oscillator
Output Multiplexer
Multi
Input Multiplexer 6 GHz Amplifier
Input Filter
Downlink Signal 3.7 to 4.2 GHz
TWT Amplifier 4 GHz Amplifier
Transponder
Mixer
4
2.1.1 Active satellite
An active satellite is one which has transmitting equipment abroad such as a transponder. It is
a device which receives a signal from earth, amplifies it and retransmits it back to earth. Its
advantages are requirement of lower power earth station, cheaper, not open to random use
and directly controlled by operators from ground.
2.1.2 Passive satellite
Passive satellite is one that doesn’t reflect or scatter the incident radiation from ground
station. Passive satellite relays would require surface transmitters of greater power than that
of an active satellite relay, however the active satellite relays must carry abroad receiving and
transmitting equipment and the necessary power sources. Some of the disadvantages of the
Passive satellites are:
? Earth Stations require high power (10 kW) to transmit signals strong enough to
produce an adequate return echo.
? Large Earth Stations with tracking facilities were expensive.
? A global system would have required a large number of passive satellites accessed
randomly by different users.
? Control of satellites not possible from ground
2.2 Different Types of Orbit
Figure 3: Different types of orbits for satellite communication (Hussaini, 2017).
5
The most unique thing about satellites is the way they orbit or rotate along the different paths
they follow at very different heights above Earth. A satellite fired into space might fall back
to Earth just like a stone tossed into the air due to gravitational force. To stop that happening,
satellites have to keep on moving all the time so, even though the force of gravity is pulling
them towards the center of the earth, they will never actually crash back to Earth.
Some turn at the same rotational rate as Earth so they’re effectively fixed in one position
above our head, while others go much faster. Although there are many different types of
satellite orbits, they come in three basic varieties, low, medium, and high—which are short,
medium, and long distances above Earth, respectively.
2.2.1 Low Earth Orbit (LEO): 500-2000 km above the earth
Figure 4: Low earth orbit (Reddy, n.d.).
Some Satellites tend to be quite close to Earth—often just a few hundred kilometers up—and
follow an almost circular path called a low-Earth orbit (LEO). The distance of the Low Earth
Orbit extends from 160km above Earth and ends at 2000km. Satellites in this orbit have an
orbital period in the range of 90-120 minutes. It is impossible to achieve an orbit below
160km without artificial thrusters because of the atmospheric drag at that altitude.
The mean orbital velocity of any satellite that needs to reach LEO should be 7.5km/s
(27,000km/h). The satellites have to move very fast in order to overcome Earth’s gravity, and
since they have a relatively small orbit as they are close to the earth, they cover large areas of
the planet quite quickly and never stay over one part of Earth for more than a few minutes.
The low earth orbit is the most crowded and accessible realm of all other orbits. More than
800 satellites are currently available in orbit within the Low-Earth Orbit region. The most
popular of these is the International Space Station and the Iridium network of communication
satellites.
6
? Advantages and disadvantages
Due to shorter distance range the Low-Earth orbit is chosen as communication and imaging
satellite. Due to the low altitude, communication signals require less power and time to travel
between the different Earth stations and the satellites. Moreover the imaging satellites can
capture very detailed pictures and views as per our wish.
Satellites for the Low-Earth orbit are easier to build and can be cheaper than their
counterparts in higher orbits. It is a very popular orbital choice for hobbyists who wish to
launch CubeSats. CubeSats are incredibly tiny satellites used for small amounts of data
collection and other experiments.
However, with the advantage of easy launching of a satellite into this orbit has inadvertently
contributed to the issue of space debris. Perhaps, the International Space Station uses layers
of shields to protect itself from space debris which is not good for satellite. Also, Satellites in
this orbit have to deal with atmospheric drag therefore they usually have a shorter lifespan
compared to the geostationary satellites (L.Ronga, 2003). These orbits are much closer to the
Earth (500-2000 Km) only, and requires the satellites to travel at a very high speed in order to
avoid being pulled out of orbit by Earth’s gravity. At LEO, a satellite can encircle around the
Earth in approximately one and a half hours.
2.2.2 Medium Earth Orbit (MEO): 8,000-20,000 km above the earth
Figure 5: Medium earth orbit (Reddy, n.d.).
The Medium Earth Orbit is also known as the Intermediate Circular Orbit. All orbits above
low-earth orbit and below geostationary orbit are said to be in medium-earth orbit. To be
precise, MEO extends from 2000km and ends right below 35,786km. Satellites in this region
have an orbital period ranging from 2-24 hours.
7
A medium-Earth orbit (MEO) is about 10 times higher up than a LEO. For an example the
GPS navstar satellites are in MEO orbits roughly 20,000 km (12,000 miles) above our heads
and take 12 hours to “loop” the planet. Their orbits are semi-synchronous, which means that,
while they’re not always exactly in the same place above our heads, they pass above the same
points on the equator at the same times each day.
? Advantages and disadvantages
The medium earth orbit is very useful for providing information about the connectivity and
navigation to the polar region because an orbital period of 12 hours can be achieved by the
satellites in this region. That is a unique period that allows the satellites to rotate around the
Earth two times in a day. The main purpose of all the satellites in the MEO are for
communication, navigation, and to provide a gravity-less environment for scientific
experiments to carry out peacefully.
However, with the increase in altitude compared to LEO, propagation delay will also begin to
creep into the transmission of signals. As a result the power required to transmit these signals
will also increase. Thus, satellites in this region are more expensive as compared to the
satellites in the low-earth orbit. Also similar to the LEO, the satellites in this orbit also have
to consider atmospheric drag too. The interference from the upper layers of the atmosphere
reduces the lifespan of these satellites in comparison with satellites in the GEO. The charged
particles in this region can hurt the performance of satellites.
2.2.3 Geostationary Earth Orbit (GEO) Beyond 36,000 km above the earth
Figure 6: Geostationary earth orbit (Reddy, n.d.).
Geostationary or Geosynchronous earth orbit is also sometimes called as High Earth Orbit
due to large distance between the earth and its orbit. Most of the satellites have orbits at a
carefully chosen distance of about 36,000 km (22,000 miles) from the surface of the earth.
8
This distance ensures that they take exactly one day to orbit Earth and always return to the
same position above it, at the same time of day. Such a high-Earth orbit satellite is sometimes
called as geosynchronous (because it’s synchronized with Earth’s rotation) or geostationary (if
the satellite stays over the same point on Earth all the time). Any orbit beyond the
geostationary orbit is known as high earth orbit. High earth orbit is loosely attributed to any
orbit beyond 35,786km.
Usually, the satellites in this orbit have an orbital period longer than a day i.e., 24 hours. Due
to this, all satellites in this orbit appear to be retrograded. Communications satellites are
usually parked in geostationary orbits so their signals always reach the satellite dishes
pointing up at them. Weather satellites often use geostationary orbits because they need to
keep gathering cloud or rainfall images from the same broad part of Earth from hour to hour
and day to day (unlike LEO scientific satellites, which gather data from many different places
over a relatively short period of time, geostationary weather satellites gather their data from a
smaller area over a longer period of time).
? Advantages and disadvantages
Satellites falling in HEO or GEO regions are useful to study about our planet’s
magnetosphere and for other astronomical observations and research. These satellites face
less exposure to atmospheric drag as compared to satellites in the LEO/MEO orbits.
Communication delays and high costs of manufacturing and launching a satellite into this
orbit are some of the areas of concern as it has quite far from earth.
Orbiting at the height of 22,282 miles above the equator (35,786 km), the satellite travels in
the same direction and at the same speed as the Earth’s rotation on its axis taking 24 hours to
complete a full trip around the globe. Thus, as long as a satellite is positioned over the
equator in an assigned orbital location, it will appear to be stationary with respect to a
specific location on the Earth.
A single geostationary satellite can view approximately one third of the Earth’s surface. If
three satellites are placed at the proper longitude, the height of this orbit allows almost all of
the Earth’s surface to be covered by the satellites.
9
Satellite
communication
2. The satellite amplifies the
incoming signal and changes
the frequency.
3. The satellite
transmits the signal
back to Earth.
4. The ground equipment
receives the signal
1. An uplink Earth
station or other ground
equipment transmits
the desired signal to the
satellite
3 WORKING OF SATELLITE COMMUNICATION
Figure 7: Working of Satellite Communication in brief.
The above diagram depicts a brief description about how the satellite communication
happens. Firstly from the ground stations, the transmitter will transmit the desired signals to
the satellite and the satellite in the space will detect or receive that particular signal and
amplifies it. Then the amplified version of the signal will be retransmitted back to the earth
and again the converted and the original signal will be received.
Firstly the users are connected to the earth station through a terrestrial network such as
telephone switch or a dedicated link to the earth station. Then the user generates a baseband
signal which will be processed through a terrestrial network and will be transmitted to a
satellite.
10
The satellite which consists of a large number of repeaters in space receives the modulated
RF carrier in its uplink frequency spectrum from all the earth stations in the network and it
will amplify these carriers signals and also retransmits all the signals back to the earth
stations in the down link frequency spectrum (Joseph N Pelton, 1998).
To avoid interference of the frequency signals, the downlink frequency spectrum should be
different from the uplink frequency spectrum. Therefore the signal at the receiving earth
station is processed to get back the baseband signal, it is sent to the user through a terrestrial
network. There are many frequency bands utilized by satellites but the mostly used bands are
the uplink frequency of 6GHz and the downlink frequency of 4 GHz. Actually the uplink
frequency band is 5.725 to 7.075 GHz and the actual downlink frequency band is from 3.4 to
4.8 GHz.
Figure 8: Basic Elements of Satellite Communications System (Visahli, 2014).
3.1 Working of Uplink and Downlink
For an instance you want to send something like a TV broadcast from one side of Earth to the
other, there are three stages involved. Firstly, there will be an uplink, where data is beamed
up to the satellite from a ground station from the Earth. Then the satellite processes the data
using a number of onboard transponders (radio receivers, amplifiers, and transmitters). These
boost the incoming signals and change their frequency, so incoming signals do not interfere
with outgoing signals.
11
Different transponders in the same satellite are used to handle different TV stations carried
on different frequencies. Finally there will be the downlink, where data is sent back down to
another ground station which can be anywhere on Earth. Although for a single uplink, there
may be millions of downlinks, for example, if many people are receiving the same satellite
TV signal at once. Therefore a communications satellite might relay a signal between one
sender and receiver (fired up into space and back down again, with one uplink and one
downlink), satellite broadcasts typically involve one or more uplinks (for one or more TV
channels) and multiple downlinks (to ground stations or individual satellite TV subscribers)
(E.Lutz, 2000).
The following table shows the main frequency bands used for satellite links.
Table 1: Main frequency bands used by satellite communication system (Reddy, n.d.).
The band’s reception on Earth is subject to an inverse relationship between frequency and
wavelength. When frequency increases, wavelength decreases and vice versa. The larger the
wavelength, the bigger the antenna necessary to receive. The two frequently bands that are
used mostly are the C-band and the Ku-band. The C-band has an uplink frequency of 6 GHz
and a downlink frequency of 4 GHz. The minimum site of an average C-band antenna is
approximately 2 to 3 meters in diameter.
Another type of frequency band is called as Ku-band which has an uplink frequency of 14
GHz and a downlink frequency of 11 GHz. Ku-bands can have much smaller antennas as
higher frequency means shorter wavelength. The smallest of these antennas can be 18 inches
in diameter. This is the type of antenna used with home entertainment satellite dishes.
Ku-Band Satellite Antenna.
Frequency Band Downlink Uplink
C 3,700-4,200 MHz 5,925-6,425 MHz
Ku 11.7-12.2 GHz 14.0-14.5 GHz
Ka 17.7-21.2 GHz 27.5-31.0 GHz
12
3.2 The Transponder
Figure 9: Block diagram of the Transponder (Vamsiram’s Jyothi Celestia, n.d.).
A wireless communications device usually attached to a satellite. A transponder receives and
transmits radio signals at a prescribed frequency range. After receiving the signal a
transponder will at the same time broadcast the signal at a different frequency. The term is a
combination of the words transmitter and responder. Transponders are used in satellite
communications and in location, identification and navigation systems.
In a transponder for amplification of a received signal into an antenna to a signal for
retransmission, and where the retransmitted signal possibly may have information
superimposed, a quenched oscillator is incorporated as amplifying element. The oscillator is
preferably of super regenerative type and exhibits negative resistance for the received signal.
Transponders according to the present invention may be introduced as system elements in a
wireless or wire based network to work as intelligent or unintelligent connections in the
network. The transponders can also be used in positioning systems (D.K.Paul F. Faris, 1992).
Satellite
Antenna
Low Noise
Amplifier
Carrier
Processor
Power
Amplifier
Duplexer
13
4 APPLICATIONS OF SATELLITE COMMUNICATION
4.1 Weather Forecasting
Certain satellites are particularly designed to monitor the climatic conditions of earth i.e.,
weather forecasting. They continuously monitor the assigned areas of earth and predict the
weather conditions of that region. This is done by taking images of earth from the satellite.
These images are transferred using assigned radio frequency a particular earth station. These
satellites are also exceptionally useful in predicting disasters like hurricanes, and monitor the
changes in the Earth’s vegetation, ocean color, and ice fields.
4.2 TV and Radio Broadcast
These dedicated satellites are responsible for making hundreds of channels across the globe
available for everyone. They are also responsible for broadcasting live news, matches, world-
wide radio services. These satellites require at least 30-40 cm sized dish to make the channels
available globally.
4.3 Military Satellites
These satellites are often used for gathering intelligence, as a communications satellite used
for military purposes, or as a military weapon during war time. A satellite by itself is neither
military nor civil. It is the kind of payload it carries that enables one to take a correct decision
regarding its military or civilian character.
4.4 Navigation Satellites
The system allows for precise localization and tracking all over the world, and with some
additional techniques, the precision is in the range of some meters distance. Ships and aircraft
also rely on GPS as an addition traditional navigation systems. Nowadays many vehicles
come with installed GPS receivers which helps to track the accidents and lost vehicles. This
system is also used, e.g., for fleet management of trucks or for vehicle localization in case of
theft.
14
4.5 Global Telephone
The first applications of satellites for communication was the establishment of international
telephone systems during early days. Instead of using cables it was sometimes faster to
launch a new satellite. However, fiber optic cables are still replacing satellite communication
across long distance as in fiber optic cable, light is used as a source instead of radio
frequency, hence making the communication much faster and more efficient (and of course,
reducing the delay caused due to the amount of distance a signal needs to travel before
reaching the destination) (B.I.Edelson, 1996).
Using satellites, to typically reach a distance approximately about 10,000 km away, the signal
needs to travel almost 72,000 km, i.e., sending data from ground to satellite and (mostly)
from satellite to another location on earth. This cause substantial amount of delay and this
delay becomes more prominent for users during voice calls or other communication process.
4.6 Global Mobile Communication
The basic purpose of satellites for mobile communication is to extend the area of network
coverage. Cellular phone systems, such as AMPS and GSM and their successors do not cover
all parts of a country. The some of areas that are not covered usually have low population
where it is too expensive to install a base station. With the integration of satellite
communication, however, the mobile phone can switch to satellites offering world-wide
connectivity to a customer. Satellites cover a certain area on the earth and has many
advantages for communication process.
15
5 ADVANTAGES AND DISADVANTAGES OF SATELLITE
COMMUNICATION
Satellite Communication is one of the most impressive spin-off from space programs, and
made a major contribution to the international communication. Satellite plays a very
important role in telephone communication, TV and radio program distribution and other
certain communications (D.K.Paul F. Faris, 1992).
5.1 Advantages
1. Point to multipoint communication is possible whereas terrestrial relay are point to point,
this is why satellite relay are wide area broadcast
2. Circuits for the satellite can be installed rapidly. Once the satellite is in Position, Earth
Station can be installed and communication may be established within some day or even
hours.
3. Mobile communication cab be easily achieved by satellite communication
because of its flexibility in interconnecting mobile vehicles.
4. As compared to fiber cable, the satellite communication has the advantage of
the quality of transmitted signals and the location of Earth Stations. The sending and
receiving information independent of distance.
5.2 Disadvantages
1. With the Satellite in position the communication path between the terrestrial transmitter
and receiver is approximately 75000 km long.
2. There is a delay of ¼ sec between the transmission and reception of a signal because the
velocity of electromagnetic wave is 3* 10^5 Km/second.
3. The time delay reduces the efficiency of satellite in data transmission and long file transfer,
which carried out over the satellites.
4. Over-crowding of available bandwidth due to low antenna gains is occurred.
5. High atmosphere losses above 30 GHz limit the carrier frequency.
16
6 CONCLUSION
The satellite communication in telecommunications, uses the artificial satellites to provide
communication links between various points on Earth stations. The Satellite communications
play an important role in the telecommunications system all over the world. Approximately
about 2,000 artificial satellites orbiting around the Earth and relay analog and digital signals
carrying voice, video, and data to and from one or many locations worldwide (L.Ronga,
2003). Satellite communication has two main components: the ground station, which consists
of fixed or mobile transmission, reception, and ancillary equipment, and next the space
segment, which primarily is the satellite itself.
The typical satellite link involves the transmission or up-linking of a signal from a ground
station to a satellite. The satellite then at the space receives the signal and amplifies the
original signal and retransmits it back to Earth, where it is received and re-amplified by Earth
stations and different terminals. Satellite receivers on the ground or the earth station includes
direct-to-home satellite equipment, mobile reception instruments in aircraft, satellite
telephones, and handheld devices.
17
REFERENCES
B.I.Edelson, a. G. (1996). Laser Satellite Communications, Program, Technology and
Applications. IEEE-USA Aerospace Policy Commitee Report.
D.K.Paul F. Faris, R. a. (1992). Optical Intersatellite Link: Application to Commmercial
Satellite Communication. Washington: 14th proc.,AIAA, Int. Communication
Satellite System.
DAEnotes. (2018, January 8). Satellite Communication. Retrieved from DAEnotes:
https://www.daenotes.com/electronics/communication-system/satellite-
communication.
E.Lutz, M. A. (2000). Satellite System for Personal and Broadband Communication. USA:
Springer, NY.
Hussaini, U. (2017, September 21). Types of Orbits. Retrieved from Technobyte:
https://www.technobyte.org/satellite-communication/low-medium-high-earth-orbits-
types-of-orbits/.
Joseph N Pelton, A. U. (1998). Global Satellite Communication Technology and System.
ITRI Maryland, USA: WTEC Report .
L.Ronga, T. R. (2003). A Gateway arctiecture for IP Satellite networks with dynamic
resource management and diffServQos provision. International Journal of Satellite
Communication and Networking, 351-366.
R.Elbert, B. (2008). Introduction to Satellite Communication. (3. E. Book, Ed.) Arctech
House, 685, Canton Street, Norwood, MA 02062.
Reddy, M. M. (n.d.). Lecture Notes-Mrcet. Retrieved from Sateliite communication:
https://mrcet.com/downloads/digital_notes/ECE/IV%20Year/Sattelite%20Communic
ations.pdf.
Roddy, D. (1995). Satellite Communication. McGraw Hill Text.
University of Science and Technology of China. (2018, January 19). University of Science
and Technology of China. Retrieved from PHYSORG: https://phys.org/news/2018-
01-real-world-intercontinental-quantum-enabled-micius.
Vamsiram’s Jyothi Celestia. (n.d.). Tutorials Point. Retrieved from Transponder block
Diagram: https://www.tutorialspoint.com/about/contact_us.htm.
Visahli. (2014, November 8). Ssatellite Communication. Retrieved from Slideshare:
https://www.slideshare.net/dhivya299/satellite-by-vishali.
