What is a Radar ?
Radar is an acronym for "Radio detection and ranging" .
Radar is an electronic device used to detect or measure the distance and speed of an object (where it can be either flying object or stationary object or moving object.
They can work efficiently even under extreme weather conditions.
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Long-range radar antenna,.
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Radars use high frequency radio waves (called microwaves) which travel at the speed of light. A transmitter at the radar station sends out the waves via an antenna. These waves get reflected by some obstacle and produce an echo. Back at the station, a receiver picks up these reflected waves. The time taken between the sending and receiving is also recorded.
In this way, with the help of echoes Radars determine the direction and distance of reflecting objects.
History of Radar:
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| Sir Robert Alexander Watson-Watt |
Radar technology began with experiments
using radio waves in the laboratory of German physicist Heinrich Hertz in 1887.
He discovered that radio waves could be sent through many different materials
but were reflected by others. In 1900, a radio pioneer, Nikola Tesla, noticed
that large objects could produce reflected radio waves that are strong enough
to be detected. He knew that reflected radio waves were really radio echoes. So
he predicted that such echoes could be used to find the position and course of
ships at sea.
Before 1935 radar were very crude they
could detect only large objects like ships.
However in February 1935 , , Sir
Robert Alexander Watson-Watt (13 April 1892
– 5 December 1973)who was a Scottish pioneer of radar technology .Robert Watson watt made a crucial breakthrough he
devised a radar that could spot something as small as an aircraft applying
scientific principles already well understood at the time . After the success of his invention, Watson-Watt was sent to the US in
1941 to advice on air defense after Japan’s attack on Pearl Harbor. He was
elected a Fellow
of the Royal Society in 1941, was given a knighthood in 1942 and was awarded the US Medal for Merit in 1946.
Basic design
of Radar:
Basic block
diagram of radar
Working of a radar:
Transmitter:
The radar transmitter
produces the short duration high power fry
pulses that are radiated into space
by antenna.
Duplexer : The Duplexer alternatively switches
the antenna between transmitter
and receiver so that only need to be used. The
switching is very necessary because the
high power pulses of the transmitter
would destroy the receiver if the transmitted
energy was allowed to enter the
receiver.
Receiver: The receiver amplifies and
demodulates the received RF signal.
The receiver provides video signals on the
output.
Radar
antenna: The radar
antenna radiates transmitter energy into space and
the received signal which
means echo signal is given to the receiver.
Display: A radar display is an
electronic device to present radar data
to the
operator. The receiver converts all received RF signal into a
continuous
electronic analog signal of varying (or oscillating) voltage.so The display
present to
the operator a continuous ,easily understandable, graphic picture of
the relative
position of the targets.
Classification of Radar:
There are different types of radars
classified in different ways.
1. Classification based on specific
function:
A).primary
radar
B).secondary
radar
2. Classification based on scan pattern:
A).conical
scans radar
B).tracking
while scan radar
C).mono
pulse scans radar
D).electronic
scans radar
3. Classification based on application:
A).surveillance
radar
B).tracking radar
C).meteorological
radar
D).imaging
radar
E).radar
altimeter
Applications of Radar:
1.weather
monitoring
2.military
3.Air
traffic control
4.Law
enforcement and highway security
5.Aircraft
safety and navigation
6.Ship
safety
7.Space
8.Used
to study movement of insects and birds
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