This is a introductory notes about Satellite system. It contain details about the history, different type of characteristics & various applications of satellite system. It also include details about four types of orbits- LEO, MEO, HEO, GEO.

1. SATELLITE
SYSTEM
…Introduction to Satellite System…
ABSTRACT
This is a introductory notes about Satellite system.
It contain details about the history, different type
of characteristics & various applications of
satellite system. It also include four types of
orbits- LEO, MEO, HEO, GEO.
Supervised By
Pranab Bandhu Nath
(Senior Lecturer)
CSE Department
City University, Dhaka
Submitted By
Shamima Akther| ID - 1834902616
CSE 317 : Computer Networks

2. Satellite System
Introduction & Definition:
In General terms, as a definition of satellite it can be said as, a Satellite is a smaller object that
revolves around a larger object in space. As for example, moon is the satellite of earth and earth
is the satellite of sun. Nowadays the artificial spacecrafts are named satellite as well, because
they are launched by a rocket to the space and are kept there by gravitational force revolving
around the earth similarly as planets can orbit around the other planets. So, we can say a satellite
can be natural like moon or artificial(human made). That means any object that moves in a
curved path around a planet is satellite. In a communication context, Satellites are highly
specialized wireless receivers/transmitters, which main function is to relay the radio frequency
waves and the encoded information in them from one corner of the world to another. Currently
there are hundreds operating satellites above the earth.
Satellites are used for many purposes like, weather forecasting, digital transmission, scientific
research and development etc as it can cover a wide area on the surface of the earth.
History Of Satellite System:
❖ The science fiction writer Arthur C. Clarke from England could be name the father of
satellite communications, because he was the first who proposed to launch a satellite into
the earth orbit where satellites speed would match with the rotation of the earth. That
orbit, which is 35786 km height above the planet surface today is known as geostationary
orbit but sometimes it is called Clarke orbit in honor of his work and ideas [Held91].
❖ The first world’s satellite Sputnik 1 as big as basketball was launched by Russia (former
Soviet Union) in 1957(October) with the aim to relay the signal of Morse code
[Wiki06b].
❖ In 1960, First Reflecting communication satellite, ECHO.
❖ In 1963, First Geostationary satellite, SYNCOM.
❖ In 1965, First Commercial geostationary satellite, “Early Bird” (INTEKSAT I): 240
duplex telephone channels or 1 TV channel, 1.5 year lifetime.
❖ In 1976, Three MARISAT satellites for maritime communication.
❖ First mobile satallite telephone system INMARSAT – A was in 1982.
❖ The first commercial satellite PAS-1 was launched by American satellite operator
PanAmSat in 1984 as the governmental providers were able to offer quite poor services at
the high cost.
❖ In 1988, First satellite system for mobile phones and data communication, INMARSAT –
C.
❖ In 1993, First digital satellite telephone system.
❖ In 1998, Global satellite systems for small mobile phones.

3. Characteristics of Satellite Systems:
▪ Specialized antennas are used to provide smaller footprints and higher transmitting
power.
▪ Several satellites are needed to ensure global coverage. The same frequency spectrum is
also used by MEO and GEO.
▪ In MEO systems, the moving satellites orbit at a height of about 5,000 to 12,000 km
above the earth and have a latency of about 70 to 80 ms.
▪ Satellites have been launched for various applications and are placed at different
attributes. Moreover their weights are also dissimilar.
▪ Provides connections between the earth-based base station and the satellites.
▪ A satellite typically has a large footprint, which can be up to 34% of the earth's surface
covered and therefore it is difficult to reuse frequencies.
▪ The Global coverage of small mobile phones and data transmission typically cause high
latency in the range of about 275 ms.
▪ LEO satellite are divided into little and big satellites.
▪ Little LEOs are smaller in size and are in the frequency range of 148 to 150.
▪ The GEO satellites, which are at an altitude of 35,768 km, orbit in the equatorial plane
with zero degree inclination and complete exactly one rotation in a day.
▪ The antennas are at fixed positions, and an uplink bank (reverse band) of 1634.5 to
1660.5 MHz and a downlink band (forward band) in the range of 1530 to 1559 MHz, are
employed.
▪ Ku band frequencies (11 and 13 GHz) are employed for connection between the base
station (earth station) and the satellites.
▪ Big LEO satellites have adequate power and bandwidth to provide various global mobile
services (i.e. data transmission, paging, facsimile, and position location) along with good
quality voice services for mobile systems such as handled devices and vehicular
transceivers.
Applications Of Satellite Systems:
Artificial satellites revolve around the earth because of the gravitational force of attraction
between the earth and satellites. Unlike the natural satellites (moon), artificial satellites are used
in various applications. The various applications of artificial satellites includes :-
Weather Forecasting:
Weather forecasting is the prediction of the future of weather. The satellites that are used to
predict the future of weather are called weather satellite. Weather satellites continuously monitor
the climate and weather conditions of earth. They use sensors called radiometers for measuring
the heat energy released from the earth surface. Several satellites deliver pictures of the earth
using infrared or visible light. Weather satellites Also predict the most dangerous storms such as
hurricanes, yash, amphan etc.

4. Navigation:
Generally, navigation refers to determining the geographical location of an object. The satellites
that are used to determine the geographic location of aircrafts, ships, cars, trains or any other
object are called navigation satellites. GPS (Global Positioning System) is an example of
navigation system. It allows the user to determine their exact location at anywhere in the world.
Astronomy:
Astronomy is the study of celestial objects such as stars, planets, galaxies, natural satellites,
comets etc. The satellites that are used to study or observe the distant stars, galaxies, planets etc.
are called astronomical satellites. They are mainly used to find the new stars, planets, and
galaxies. Hubble space telescope is an example of astronomical satellite. It captures the high
resolution images of the distant stars, galaxies, planets etc.
Satellite television:
Satellite television or satellite TV is a wireless system that uses communication satellites to
deliver the television programs or television signals to the users or viewers. TV or television
mostly uses geostationary satellites because they look stationary from the earth. Hence, the
signal is easily transmitted. When the television signal is send to the satellite, it receives the
signal, amplifies it and retransmit it back to the earth. The first satellite television signal was
send from Europe to North America by using the Telstar satellite.
Satellite phone:
Satellite phone is a type of mobile phone that uses satellites instead of cell towers for
transmitting the signal or information over long distances. Mobile phones that use cell towers
will work only within the coverage area of a cell tower. If we go beyond the coverage area of a
cell tower or if we reach the remote areas, it becomes difficult to make a voice call or send text
messages with the mobile phones. Unlike the mobiles, satellite phones have global coverage.
Satellite phones uses geostationary satellites and low earth orbit (LEO) satellites for transmitting
the information.
Military Satellite:
Military satellite is an artificial satellite used by the army of various purposes such as spying on
enemy countries, military communication and navigation. Military satellite obtain the secret
information from the enemy countries. These satellite also detect the missiles launched by the
other countries in the space. Military satellites are used by Armed Forces to communicate with
each other. These satellites also used to determine the exact location of an object.
Satellite internet:
Satellite internet is a wireless system that uses satellites to deliver the internet signals to users.
High-speed internet is the main advantage of satellite internet. Satellite internet does not use
cable systems, but instead of it uses satellites to transmit the information or signal.

5. Satellite radio:
Satellite radio is a wireless transmission service that uses orbiting satellites to deliver the
information or radio signals to the consumers. It is primarily used in the cars. When the ground
station transmit signal to the satellite that is revolving around the earth, the satellite receives the
signal, amplifies it and redirects the signal back to the earth (radio receivers in the cars).
Types Of Orbits:
There are several types of Earth orbit and each offers certain advantages and capabilities:
Low Earth Orbit (LEO)
LEO is commonly used for communication and remote sensing satellite systems as well as the
International Space Station (ISS) and Hubble Space Telescope.
Medium Earth Orbit (MEO)
MEO is commonly used for navigation systems, including the U.S. Global Positioning System
(GPS).
Geosynchronous Orbit (GSO) & Geostationary Orbit (GEO)
Objects in GSO have an orbital speed that matches the Earths rotation, yeilding a consistent
position over a single longitude. GEO is a kind of GSO. It matches the planets rotation but GEO
objects only orbit Earths equator and from the ground perspective, they appear in a fixed position
in the sky. GSO and GEO are used for telecommunications and Earth observation.
Highly Elliptical Orbit (HEO)
An HEO is oblong, with one end nearer the Earth and other more distant. Satellites in HEO are
suited for communications, satellite radio, remote sensing and other appications.

6. References:
https://www.physics-and-radio-electronics.com/satellite-
communication/applicationsofsatellites.html?fbclid=IwAR0PXiqej5jHDkcv0loTyKeLia_DWwP
_vTXJyecmwsSsjsq4NhU59dg3NQ8#:~:text=The%20satellites%20that%20are%20used%20to
%20determine%20the%20geographic%20location,at%20anywhere%20in%20the%20world
https://www.javatpoint.com/applications-of-satellite-systems
https://www.javatpoint.com/characteristics-of-satellite-systems
https://www.javatpoint.com/history-of-satellite-systems
https://www.tutorialspoint.com/satellite_communication/satellite_communication_introduction.h
tm
https://www.grin.com/document/75050
https://www.spacefoundation.org/space_brief/types-of-
orbits/?fbclid=IwAR1K5A206DrpR3BgVyD_xT0W11xNOXdnJ8SHuzgLCUwc6rYfmNLVy3
XJpcs