Ppt on satelite

1. What is Satellite?
What is Satellite Communication?
Block Diagram of Satellite Communication.
Needs of Satellite Communication.
How Satellite Communication Work?
History of Satellite Communication.
Satellite Architecture.
Elements of Satellite Communication.

2. Orbits for Satellite Communication.
Evolution of Satellite Communication.
Services of Satellite Communication.
Frequency Bands of Satellite Communication.
Advantage of Satellite Communication.
Disadvantage of Satellite Communication.
Application of Satellite Communication.
The Future of Satellite Communication.
Conclusion.

4. A satellite is an object that moves around a larger object.
Earth is a satellite because it moves around the sun.
The moon is a satellite because it moves around Earth.
Earth and the moon are called "natural" satellites.
But usually when someone says "satellite," they are talking
about a "man-made" satellite.
 Man-made satellites are machines made by people.

5. Why Are Satellites Important?
Satellites fly high in the sky, so they can see large areas of Earth at one
time. Satellites also have a clear view of space. That's because they fly
above Earth's clouds and air.
Before satellites, TV signals didn't go very far. TV signals only travel in
straight lines. So they would go off into space instead of following Earth's
curve. Sometimes they would be blocked by mountains or tall buildings.
With satellites, TV signals and phone calls can be sent up to a satellite.
The satellite can then send them back down to different spots on Earth.
With satellites, TV signals and phone calls can be sent up to a satellite.
The satellite can then send them back down to different spots on Earth.

7. Satellite communication is the method of transporting information from
one place to another using a communication satellite in orbit around the
Earth.
Satellite communication, in telecommunications, the use of artificial
satellites to provide communication links between various points on
Earth.
A communication satellite is an artificial satellite that transmits the
signal via a transponder by creating a channel between the transmitter
and the receiver located at different locations on the Earth.
Telephone, radio, television, internet, and military applications use
satellite communications. Believe it or not, more than 2000 artificial
satellites are hurtling around in space right above your heads.

11. We know that there are different ways to communicate and
the propagation of these waves can take place in different
ways.
 Ground wave propagation and skywave propagation are
the two ways in which communication took place for a
certain distance
The maximum distance covered by them is 1500 km and
this was overcome by the introduction of satellite
communication

13. •The communication satellites are similar to
the space mirrors that help us in bouncing the
signals such as radio, internet data, and
television from one side of the earth to
another.
•There are three stages that are involved
which explain the working of satellite
communications. These are:
•Uplink
•Transponders
•Downlink

16. The idea of communicating through a satellite first appeared
in the short story titled “The Brick Moon,” written by the
American clergyman and author Edward Everett Hale and
published in The Atlantic Monthly in 1869–70.
The story describes the construction and launch
into Earth orbit of a satellite 200 feet (60 metres) in diameter
and made of bricks.
The brick moon aided mariners in navigation, as people
sent Morse code signals back to Earth by jumping up and
down on the satellite’s surface.
The first practical concept of satellite communication was
proposed by 27-year-old Royal Air Force officer Arthur C.
Clarke in a paper titled “Extra-Terrestrial Relays: Can Rocket
Stations Give World-wide Radio Coverage?” published in the
October 1945 issue of Wireless World.

17. The first artificial satellite, Sputnik 1, was launched successfully
by the Soviet Union on October 4, 1957.
Sputnik 1 was only 58 cm (23 inches) in diameter with four
antennas sending low-frequency radio signals at regular intervals.
It orbited Earth in a elliptical orbit, taking 96.2 minutes to
complete one revolution.
It transmitted signals for only 22 days until its battery ran out and
was in orbit for only three months, but its launch sparked the
beginning of the space race between the United States and the
Soviet Union.
The successful development of satellite technology paved the
way for a global communications satellite industry.

20. Satellite communication systems operate in two
configurations:
(a)mesh; and
(b) (b) star.
In mesh configuration, two satellite terminals communicate
directly with
each other.
In star configuration, there will be a central station (called a
hub), and remote
stations communicate via the hub.
The architecture of a satellite communication system is
shown in Figure :

23. The system consists of two segments:
1. Space segment
2. Ground segment
Space segment: The space segment consists of the satellite, which has
three main systems: (a) fuel system; (b) satellite and telemetry control
system; and (c) transponders.
The fuel system is responsible for making the satellite run for years.
The satellite and telemetry control system is used for sending
commands to the satellite as well as for sending the status of onboard
systems to the ground stations.
The transponder is the communication system, which acts as a relay in
the sky. The transponder receives the signals from the ground stations,
amplifies them, and then sends them back to the ground stations.
he reception and transmission are done at two different frequencies.
The transponder needs to do the necessary frequency translation.

24. Continue…
Ground segment: The ground segment consists of a number of Earth
stations.
 In a star configuration network, there will be a central station called
the hub and a number of remote stations.
Each remote station will have a very small aperture terminal (VSAT),
an antenna of about 0.5 meter to 1.5 meters.
Along with the antenna there will an outdoor unit (ODU), which
contains the radio hardware to receive the signal and amplify it.
The radio signal is sent to an indoor unit (IDU), which demodulates
the signal and carries out the necessary baseband processing.
The communication path from a ground station to the satellite is
called the uplink.
The communication link from the satellite to the ground station is
called the downlink.
 Separate frequencies are used for uplink and downlink.
When a remote transmits data using an uplink frequency, the satellite
transponder receives the signal, amplifies it, converts the signal to the
downlink frequency, and retransmits it

25. The three widely used frequency bands in satellite communication
systems are C band, Ku band, and Ka band.
The higher the frequency, the smaller will be the antenna size.
However, the effect of rain is greater at higher frequencies.
The various bands of operation are:
C band: Uplink frequency band 6GHz (5.925 to 6.425 GHz)
Downlink frequency band: 4GHz (3.7 to 4.2 GHz)
Ku band: Uplink frequency band: 14GHz (13.95 to 14.5 GHz)
Downlink frequency band: 11/12GHz (10.7-11.25 GHz, 12.2-12.75
GHz)
Communication satellites operate in different frequency bands: C
band (6/4GHz), Ku band (14/ 12GHz), and Ka band (30/20GHz) band.
The higher the frequency, the smaller the antenna.
Continue….

28. Communications satellites usually have one of three primary types
of orbit, while other orbital classifications are used to further specify
orbital details.
MEO and LEO are non-geostationary orbit (NGSO).
Geostationary satellites have a geostationary orbit (GEO), which is
22,236 miles (35,785 km) from Earth's surface. This orbit has the special
characteristic that the apparent position of the satellite in the sky when
viewed by a ground observer does not change, the satellite appears to
"stand still" in the sky. This is because the satellite's orbital period is the
same as the rotation rate of the Earth. The advantage of this orbit is that
ground antennas do not have to track the satellite across the sky, they
can be fixed to point at the location in the sky the satellite appears.
Medium Earth orbit (MEO) satellites are closer to Earth. Orbital
altitudes range from 2,000 to 36,000 kilometres (1,200 to 22,400 mi) above
Earth.
The region below medium orbits is referred to as low Earth orbit (LEO),
and is about 160 to 2,000 kilometres (99 to 1,243 mi) above Earth.

29. Continue….
Low Earth orbit (LEO)
A low Earth orbit (LEO) typically is a circular orbit about 160 to 2,000
kilometres (99 to 1,243 mi) above the earth's surface and, correspondingly, a
period (time to revolve around the earth) of about 90 minutes.
Because of their low altitude, these satellites are only visible from within a
radius of roughly 1,000 kilometres (620 mi) from the sub-satellite point. In
addition, satellites in low earth orbit change their position relative to the
ground position quickly. So even for local applications, many satellites are
needed if the mission requires uninterrupted connectivity.
Low-Earth-orbiting satellites are less expensive to launch into orbit than
geostationary satellites and, due to proximity to the ground, do not require
as high signal strength (signal strength falls off as the square of the
distance from the source, so the effect is considerable). Thus there is a
trade off between the number of satellites and their cost.
In addition, there are important differences in the onboard and ground
equipment needed to support the two types of missions.

30. Satellite constellation:-
 A group of satellites working in concert is known as
a satellite constellation. Two such constellations, intended
to provide satellite phone services, primarily to remote
areas, are the Iridium and Globalstar systems. The
Iridium system has 66 satellites.
It is also possible to offer discontinuous coverage using
a low-Earth-orbit satellite capable of storing data received
while passing over one part of Earth and transmitting it
later while passing over another part. This will be the
case with the CASCADE system
of Canada's CASSIOPE communications satellite.
Another system using this store and forward method
is Orbcomm.

31. Medium Earth orbit (MEO)
A medium Earth orbit is a satellite in orbit somewhere between 2,000
and 35,786 kilometres (1,243 and 22,236 mi) above the earth's surface.
MEO satellites are similar to LEO satellites in functionality. MEO satellites
are visible for much longer periods of time than LEO satellites, usually
between 2 and 8 hours. MEO satellites have a larger coverage area than
LEO satellites. A MEO satellite's longer duration of visibility and wider
footprint means fewer satellites are needed in a MEO network than a LEO
network. One disadvantage is that a MEO satellite's distance gives it a
longer time delay and weaker signal than a LEO satellite, although these
limitations are not as severe as those of a GEO satellite.
Like LEOs, these satellites do not maintain a stationary distance from
the earth. This is in contrast to the geostationary orbit, where satellites are
always 35,786 kilometres (22,236 mi) from the earth.
Typically the orbit of a medium earth orbit satellite is about 16,000
kilometres (10,000 mi) above earth. In various patterns, these satellites
make the trip around earth in anywhere from 2 to 8 hours.

32. Examples of MEO:-
In 1962, the communications satellite, Telstar, was
launched. It was a medium earth orbit satellite designed to
help facilitate high-speed telephone signals. Although it was
the first practical way to transmit signals over the horizon, its
major drawback was soon realised. Because its orbital
period of about 2.5 hours did not match the Earth's rotational
period of 24 hours, continuous coverage was impossible. It
was apparent that multiple MEOs needed to be used in order
to provide continuous coverage.
In 2013, the first four of a constellation of 20 MEO satellites
was launched. The O3b satellites provide broadband internet
services, in particular to remote locations and maritime and
in-flight use, and orbit at an altitude of 8,063 kilometres
(5,010 mi)).

33. Geostationary orbit (GEO):-
To an observer on Earth, a satellite in a geostationary
orbit appears motionless, in a fixed position in the sky. This
is because it revolves around the Earth at Earth's
own angular velocity (one revolution per sidereal day, in
an equatorial orbit).
A geostationary orbit is useful for communications
because ground antennas can be aimed at the satellite
without their having to track the satellite's motion. This is
relatively inexpensive.
In applications that require many ground antennas, such
as DirecTV distribution, the savings in ground equipment
can more than outweigh the cost and complexity of placing
a satellite into orbit.

34. Examples of GEO[edit]
The first geostationary satellite was Syncom 3, launched
on August 19, 1964, and used for communication across
the Pacific starting with television coverage of the 1964
Summer Olympics. Shortly after Syncom 3, Intelsat I,
aka Early Bird, was launched on April 6, 1965, and placed
in orbit at 28° west longitude. It was the first geostationary
satellite for telecommunications over the Atlantic Ocean.
On November 9, 1972, Canada's first geostationary
satellite serving the continent, Anik A1, was launched
by Telesat Canada, with the United States following suit
with the launch of Westar 1 by Western Union on April 13,
1974.
Continue…

35. Molniyaorbit:-
Geostationary satellites must operate above the equator and therefore appear
lower on the horizon as the receiver gets farther from the equator. This will cause
problems for extreme northerly latitudes, affecting connectivity and
causing multipath interference (caused by signals reflecting off the ground and
into the ground antenna).
Thus, for areas close to the North (and South) Pole, a geostationary satellite
may appear below the horizon. Therefore, Molniya orbit satellites have been
launched, mainly in Russia, to alleviate this problem.
Molniya orbits can be an appealing alternative in such cases. The Molniya orbit
is highly inclined, guaranteeing good elevation over selected positions during the
northern portion of the orbit. (Elevation is the extent of the satellite's position
above the horizon. Thus, a satellite at the horizon has zero elevation and a
satellite directly overhead has elevation of 90 degrees.)
The Molniya orbit is designed so that the satellite spends the great majority of its
time over the far northern latitudes, during which its ground footprint moves only
slightly. Its period is one half day, so that the satellite is available for operation
over the targeted region for six to nine hours every second revolution. In this way
a constellation of three Molniya satellites (plus in-orbit spares) can provide
uninterrupted coverage.

36. Polarorbit
In the United States, the National Polar-orbiting Operational
Environmental Satellite System (NPOESS) was established in 1994
to consolidate the polar satellite operations of NASA (National
Aeronautics and Space Administration) NOAA (National Oceanic and
Atmospheric Administration). NPOESS manages a number of
satellites for various purposes; for example, METSAT for
meteorological satellite, EUMETSAT for the European branch of the
program, and METOP for meteorological operations.
These orbits are sun synchronous, meaning that they cross the
equator at the same local time each day. For example, the satellites
in the NPOESS (civilian) orbit will cross the equator, going from south
to north, at times 1:30 P.M., 5:30 P.M., and 9:30 P.M.

38. Around 300 b.c. the Chinese invented gunpowder, which was later
packed into bamboo tubes to make a primitive firecracker. By 1232,
when the Chinese defended their lands from Mongol invaders during the
battle of Kai-Keng, an inventive native had decided to add the firecracker
to an arrow, in essence creating the first bottle rocket.
Ballistic weapons became commonplace in war, but rocket science
didn't really emerge until the turn of the century in America. In the early
1900s American Robert H. Goddard (1882-1945) began experimenting
with rocket propulsion—he received his first two U.S. patents in 1914 for
a liquid-fueled rocket engine and a two or three-stage solid fuel rocket.
In a technical report for the Smithsonian in 1920, Goddard outlined
how a rocket might reach the moon, causing an uproar in the scientific
community, who labeled him a crackpot. (His report, however, became
the foundation for the early rocket program of the German army, which
made further advancements in rocket science during the Second World
War.)

39. Continue…
In October 1945 British physicist (and science fiction author) Arthur
C. Clarke (1917- ) published an article in Wireless World that
described a system of manned satellites in orbit above Earth that
would distribute global communications through a "relay" service.
In the decade following the publication of Clarke's article, satellite
research was influenced by several significant scientific
advancements. The Cold War between America and the Soviet
Union brought about long-range, high-powered rocketry, including
intercontinental ballistic missiles (ICBMs). The first solar cells were
developed; these would eventually be used to power satellites.
The invention of the transistor made possible the miniaturized
electronic components necessary for lightweight space objects and
also ushered in the age of the high-speed digital computer, which
would be used to calculate and track satellite orbits.

40. The proven success of the early satellites stimulated a surge in
private sector interest in communications satellites. By 1960 officials
with AT&T had filed with the Federal Communications
Commission (FCC) for authorization to launch an experimental satellite,
catching the U.S. government with no policy in place to govern such
requests. As a result, competitive contracts were awarded by NASA to
RCA (for a medium orbit active communications satellite), AT&T (for its
own medium orbit satellite), and Hughes Aircraft Company (for a high-
orbit satellite). In July 1962 NASA launched the world's first private
sector communications satellite, AT&T's Telstar, which transmitted the
first live transatlantic telecast on July 10. Voice, television, facsimile,
and data were transmitted between the U.S. and various sites in
Europe. Telstar opened space to commercial users, sparking a
communications revolution.
Impact:->

41. Continue..
The success of the NASA-Hughes satellites presaged the most
significant event in modern satellite evolution—the launch of the first
commercial communications satellite, Early Bird, in April 1965 by
Comsat, the Communications Satellite Corporation. Just twenty years
shy of the anniversary of Arthur C.
While global communications evolved, domestic satellite systems
were also learning from the experiences of the Soviet Union, which had
launched the world's first domestic system, called Molniya, in 1965. By
the early 1970s both Canada and the United States began to develop
domestic satellite networks of their own. In Canada the first North
American domestic communications satellite, Anik, was launched in
November 1972. The first U.S. domestic communications satellite was
Western Union's Westar, launched in April 1974.

43. The services of satellite communication can be classified into the
following two categories.
One-way satellite communication link service
Two-way satellite communication link service
1.One-waySatelliteCommunicationLinkService
In one-way satellite communication link service, the information can be
transferred from one earth station to one or more earth stations through a
satellite. That means, it provides both point to point connectivity and point
to multi point connectivity.
Here, the communication takes place between first earth station
(transmitter) and second earth station (receiver) on earth’s surface through
a satellite in one direction.
Following are some of the one-way satellite communication link services.
Broadcasting satellite services like Radio, TV and Internet services.
Space operations services like Telemetry, Tracking and Commanding
services.
Radio determination satellite service like Position location service

44. Figure of ONE-WAY Satellite

45. 2.Two-waySatelliteCommunicationLinkService
In two-way satellite communication link, the information can be
exchanged between any two earth stations through a satellite. That
means, it provides only point to point connectivity.
Here, the communication takes place between first earth station
(transmitter) and second earth station (receiver) on earth’s surface
through a satellite in two (both) directions.
Following are some of the two-way satellite communication
link services.
Fixed satellite services like Telephone, Fax and Data of high bit rate
services.
Mobile satellite services like Land mobile, Maritime and Aero mobile
communication services.

46. Figure of TWO-WAYSatellite

48. Frequency Bands

49. Some other Frequency Bands

51. Advantages of SatelliteCommunication:-
Following are the advantages of Satellite Communication:
➨It is used for mobile and wireless communication applications
independent of location.
➨It covers wide area of the earth hence entire country or region can be
covered with just one satellite.
➨It provides wider bandwidth based on SCPC or MCPC allocation types.
➨It co-exists with terrestrial microwave line of sight communication.
➨It is easy to install and manage the ground station sites.
➨It does not incur much of the costs per VSAT site.
➨It is used for voice, data, video and any other information transmission.
Satellite system can be interfaced with internet infrastructure to obtain
internet service. It is also used for GPS applications in various mobile
devices for location determination.
➨It is easy to obtain service from one single provider and uniform service
is available.
➨It has small fading margin on the order of about 3dB.
➨ It is used in wide variety of applications which include weather
forecasting, radio/TV signal broadcasting, gathering intelligence in
military, navigation of ships and aircrafts, global mobile communication,
connecting remote areas etc.
➨LEO and MEO satellite types have lower propagation delay and lower
losses compare to GEO satellite. This will help them to be used for global

53. Disadvantages of SatelliteCommunication:-
Following are the disadvantages of Satellite Communication:
➨Satellite manufacturing requires more time. Moreover satellite
design and development requires higher cost.
➨Satellite once launched, requires to be monitored and controlled
on regular periods so that it remains in the orbit.
➨Satellite has life which is about 12-15 years. Due to this fact,
another launch has to be planned before it becomes un-
operational.
➨Redundant components are used in the network design. This
incur more cost in the installation phase.
➨In the case of LEO/MEO, large number of satellites are needed
to cover radius of earth. Moreover satellite visibility from earth is
for very short duration which requires fast satellite to satellite
handover. This makes system very complex.

55. Applications of SatelliteCommunication;-
There are quite a lot of applications for which
we use it. It includes the following:
Telephone
Digital cinema
Television
Internet access
Radio broadcasting
Disaster Management
Amateur radio
Military

57. Future of Satellite Communication:-
Forecasting the future is uncertain in Science. Nonetheless,
in the satellite space, there’s a trend for ever-increasing
flexibility, capacity, and service availability in addition to
increasingly lighter, more compact, more affordable, and
ergonomic personal and ground terminals.
In future, satellite communication is most likely to find
applications in satellite-oriented air traffic management,
customized land mobile radio broadcasting, and aeronautical
satellite communication. It is justified to expect incessant
gains with respect to intelligent space communications
systems. Noteworthy new technologies are yet to be developed
in the satellite communication space.
As the world economies turn out to be increasingly global
and as all global parts, the atmosphere, and the oceans are
exploited by mankind, the need for efficient wireless interlinks
through satellite and terrestrial wireless communication will
expand. Furthermore, the increase usage of space systems
(planetary, manned, and unmanned bodies) will give rise to the

58. Continue…
The future of the satellite communication
space depends upon how successful the
present satellite networks are. Seamless inter
working with terrestrial core networks and
terrestrial wireless access networks is of
utmost significance for the satellite networks’
success. With revolutionary advancements in
satellite communication, it’s possible to bring
several space-age fantasies to life.

60. Conclusion:-
The use of satellite technology, particularly in the use of
communications satellites has grown rapidly in the past thirty
years. Each day more and more uses for the satellites are being
discovered. Feeding this is the rapid advancement of
technology that allows the quick implementation of these uses.
Communications satellites will not only help out a person in
distress but allow a person walking the street in Manhasset N.Y.
USA to use their cellular phone to speak with someone in China.
More and more satellites are being launched each year to
support new and growing uses for business, military and
communication needs. Satellite communications will continue in
the right direction, UP.