Geo Stationary Satellite And Its Uses
Rajesh Shrestha1*, Department of Physics, Tribhuvan University
E-mail: [email protected]
Abstract
Satellite is a heavenly body which revolving rounds the planet in a particular orbit from a fixed
point at approximately 35786km above the earth’s surface. A single geostationary satellite is on
a line of sight with about 40 percent of the earth's surface. Three such satellites, each separated
by 120 degrees of longitude, can provide coverage of the entire planet, with the exception of
small circular regions centered at the north and south geographic poles. It provides the kind of
continuous monitoring necessary for intensive data analysis.
Keywords: Geo Stationary Satellite, Satellite
Introduction
The heavenly body which revolving round
the planet in the particular orbit is called
satellite. There are two types of satellite in
nature. They are a) Natural Satellite and b)
Artificial satellite. The satellite which
creates automatically in nature is called
natural satellite. For eg. Moon.
The satellite which is created by human
beings is called Artificial Satellite. For
eg.Geo stationary satellite. GEO satellites
primary purpose is weather imagery to
optimize forecasting. In addition to weather
imagery,
these
satellites
include
instrumentation used in environmental
monitoring communications via a relay
system. A satellite in geosynchronous (or
geostationary) are positioned a fixed point at
approximately 35,786 kilometers (19,323
nautical miles or 22,241 statute miles) above
the earth's surface. At this fixed height, the
satellite matches the Earth’s rotation speed
and allows the satellites a full-disc view at a
stationary position. To stay over the same
spot on earth, a geostationary satellite also
has to be directly above the equator.
Otherwise, from the earth the satellite would
appear to move in a north-south line every
day. A single geostationary satellite is on a
line of sight with about 40 percent of the
earth's surface. Three such satellites, each
separated by 120 degrees of longitude, can
provide coverage of the entire planet, with
the exception of small circular regions
centered at the north and south geographic
poles. A geostationary satellite can be
accessed using a directional antenna, usually
a small dish, aimed at the spot in the sky
where the satellite appears to hover. The
principal advantage of this type of satellite is
the fact that an earthbound directional
antenna can be aimed and then left in
position without further adjustment. Another
advantage is the fact that because highly
directional antennas can be used,
interference from surface-based sources, and
from other satellites, is minimized.
Purpose of GEO Satellites:
GEO satellites provide the kind of
continuous monitoring necessary for
intensive data analysis. By orbiting the
equatorial plane of the Earth at a speed
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matching the Earth's rotation, these satellites
can continuously stay above one position on
the Earth's surface. Because they stay above
a fixed spot on the surface, they provide a
constant vigil for the atmospheric "triggers"
for severe weather conditions such as
tornadoes, flash floods, hail storms, and
hurricanes. When these conditions develop
these GEO satellites are able to monitor
storm development and track their
movements.
are used in remote and isolate regions to
gather important weather, hydrological or
other environmental data. As a result, users
can
efficiently
monitor
various
environmental data related to the earth and
its natural phenomena and transmit this data
via the GEO satellite being targeted by the
respective remote station. The GEO satellite
functions as a repeater of the data back to an
earth ground stations. Stevens also designs
and manufactures a GEO receive system
called a Direct Readout Ground Station
(DRGS) and also provides an alternative
Internet Access to the GOES data using
Stevens service.
The United States normally operates two
meteorological satellites in geostationary
orbit over the equator – named GOES west
and GOES East. GOES is defined as
Geostationary Operational Environmental
Satellite. Each satellite views almost a third
of the Earth's surface:
Other instruments on board these satellites
are a Search and Rescue transponder, a data
collection and relay system for groundbased data platforms, and a space
environment monitor.
The environmental monitoring market (and
in the United States home land security
applications) uses the data collection and
relay system for data communications.
Advantages
Telemetry

A Data Collection Platform (DCP) consists
of sensor connected to a data logger and the
data logger connected to a GEO transmitter.
Stevens Water Monitoring Systems, Inc.
designs and manufactures a certified GEO
transmitter and a variety of sensors and data
loggers. Data Collection Platforms (DCP)




of
GEO
Satellite
Low communications cost (Free for
GOES)
Low maintenance
Emergency event-driven capability
Ideal for remote locations
Data
easily
shared
among
government users
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

Very reliable data transmissions as
system is supported governmental
agencies
Available for environmental or
home-land
security
monitoring
applications
Disadvantages
Telemetry









of
GEO
Satellite
Scheduled
transmission
times
assigned by governmental agency
and
based
on
Channel/Time
availability
Interference detection difficult
Troubleshooting capabilities minimal
Data is available to Government and
public
Hardware cost more expensive than
other telemetry costs
One-way transmissions
No acknowledgement of successful
data transmission.
If a transmission fails, it cannot be
repeated at a later time.
Primarily available only to Federal,
state or local governmental agencies
or
government
environmental
applications.
sponsored
monitoring
In recent years, low earth orbit (LEO)
satellite systems have become popular. This
type of system employs a fleet or swarm of
satellites, each in a polar orbit at an altitude
of a few hundred kilometers. Each
revolution takes between 90 minutes and a
few hours. Over the course of a day, such a
satellite comes within range of every point
on the earth's surface for a certain period of
time. The satellites in a LEO swarm are
strategically spaced so that, from any point
on the surface, at least one satellite is always
on a line of sight. The satellites thus act as
moving repeaters in a global cellular
network. A LEO satellite system allows the
use of simple, non-directional antennas,
offers reduced latency, and does not suffer
from solar fade. These facts are touted as
advantages of LEO systems over
geostationary satellites.
References:
1) GOES - Geostationary Operational Environmental Satellites ( USA)
http://www.oso.noaa.gov/goes/
2) GOES - Information on the GOES Data Collection System (DCS)
http://noaasis.noaa.gov/DCS/
3) GMS - Geostationary Meteorological Satellites ( Japan)
http://ghrc.msfc.nasa.gov:5721/source_documents/gms_source.html
4) MeteoSat (European Community)
http://www.eumetsat.int/
5) INSAT – Indian National Satellite System ( India)
http://www.bharat-rakshak.com/SPACE/space-satellite3.html
6) GOMS – Geostationary Operational Meteorological Satellite ( Russia)
http://margotte.univ-paris1.fr/cgms/en/ap9-08.htm
7) Feng Yun ( China)
http://www.fas.org/spp/guide/china/earth/fy-2.htm
(Note: Polar Orbiting Satellites, which are not GEO satellites, are not discussed in this background)
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