2. CONTENTS
TOPIC Slide No.
INTRODUCTION TO RADAR 3
MAJOR PARTS OF A RADAR SYSTEM 4
Working Process of RADAR 5
Distance Determination 7
Bistatic RADAR 8
Monostatic RADAR 9
Facts about RADAR 10
Basic types of RADAR 11
APPLICATIONS 13-17
List of some basic RADAR systems employed by the
INDIAN ARMY
18
CONCLUSION 19
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3. INTRODUCTION TO RADAR
RADAR stands for Radio Detection And Ranging.
It is an object-detection system that uses radio waves to determine
the range, angle, or velocity of objects.
It can be used to detect aircraft, ships, spacecraft, guided missiles,
motor vehicles, weather formations, and terrain.
This system is operated by transmitting an electromagnetic wave
and detecting the reflected signal.
The modern RADAR system can be used to extract much more
information from the reflected signal and got broader applications
but still the range detection is one of its important functions.
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4. MAJOR PARTS OF A RADAR SYSTEM
A Transmitter: The signal is first
generated using a waveform
generator and then amplified in the
power amplifier like Magnetron (an
electron tube for amplifying or
generating waves, with the flow of
electrons controlled by an external
magnetic field)
Waveguides: The waveguides are
transmission lines for transmission of
the RADAR signals.
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5. Receiver: It can be super heterodyne receiver or any other
receiver which consists of a processor to process the signal
and detect it.
Duplexer: A duplexer allows the antenna to be used as a
transmitter or a receiver. It can be a gaseous device that would
produce a short circuit at the input to the receiver when
transmitter is working.
Threshold Decision: The output of the receiver is
compared with a threshold to detect the presence of any
object. If the output is below any threshold, the presence of
noise is assumed.
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7. Distance Determination
The propagation of radio waves
happens at constant speed (the
speed of light c0) this distance is
determined from the runtime of
the high-frequency transmitted
signal. Since, the waves travel to a
target and back, the round trip
time is dividing by two in order to
obtain the time the wave took to
reach the target.
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10. Facts about RADAR
Police use radar to detect the speed of vehicles to see if they
are driving too fast.
NASA used radar to calculate the distance between the Earth
and other planets in our solar system.
A magnetic resonance imaging (MRI) test uses a form of radar
to look at the details inside the human body without cutting
the body open.
Surveyors use a form of radar called LIDAR. LIDAR uses light
waves instead of radio waves to map the earth's surface. Many
construction projects are mapped today using LIDAR.
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11. Basic types of RADAR
Primary RADAR : The transmitter radiates signal in all the
direction, of which has a minimum ratio proportion of energy signal
gets reflected back from the target to the receiver. Several
advantages of Primary RADAR are that it can operate independently
of the target and does not require any co-operation by the target
under surveillance. It is used by military purpose for detection of
aircraft or ships. The disadvantages of Primary RADAR are; it needs
high power to be radiated from the transmitter to ensure the return
of signal from the target.
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12. Secondary RADAR : This can identify between friendly targets
from the enemy target. Its working operation is based on an active
answering signal system. In addition to Primary RADAR, the SSR is
also equipped with the device called transponder in the target.
Secondary RADAR radiates a signal which is received by a
compatible transponder. After successful retrieving of the signal, the
target sends the useful information in the form of code. This
information tells the receiver about the location, altitude, status and
many other useful information of the target. The advantages of SSR
over PSR are; the received signal is much more powerful and is not
attenuated by any factors.
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13. APPLICATIONS
Military Applications:
target detection, target recognition
and weapon control (directing the
weapon to the tracked targets).
In missile system to guide the
weapon.
Identifying enemy locations in map.
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14. Air Traffic Control:
To control air traffic near airports.
The Air Surveillance RADAR is used to
detect and display the aircraft’s
position in the airport terminals.
To guide the aircraft to land in bad
weather using Precision Approach
RADAR.
To scan the airport surface for aircraft
and ground vehicle positions.
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15. Remote Sensing:
RADAR can be used for observing
weather or observing planetary
positions and monitoring sea ice to
ensure smooth route for ships.
A RADAR unit consists of a transmitter
and a receiver. The transmitter emits
pulses of microwaves, a type of radio
waves, outward in a circular pattern.
Precipitation scatters these microwaves,
sending some energy back to the
transmitter, where it is detected by
the RADAR's receiver.
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16. Ground Traffic Control:
RADAR can also be used by traffic
police to determine speed of the
vehicle, controlling the movement
of vehicles by giving warnings about
presence of other vehicles or any
other obstacles behind them.
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17. Space:
To guide the space vehicle for safe
landing on Moon or Mars
To observe the planetary systems
To detect and track satellites
To monitor the meteors
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18. List of some basic RADAR systems
employed by the INDIAN ARMY
1. Rohini radar
2. Rajendra Radar
3. The Indra Radar
4. Aerostat radar
5. Sword fish radar
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19. CONCLUSION
Ongoing research and development is constantly
increasing the existing range of applications. One of the
most important characteristics of RADARs is their
capability to penetrate cloud cover and to obtain data
either by day or by night. This is it's all-weather capability
that has contributed extensively to the various
commercial applications of RADAR. Till now, there is no
electronic system which can replace the RADAR for its
accuracy and efficiency in sensing and detection.
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