RADAR SYSTEM
Radar is an electromagnetic system for the detection and location of objects. It operates by transmitting a
particular type of waveform, a pulse-modulated sine wave for example, and detects the nature of the echo
signal. Radar is used to extend the
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capability of one's senses for observing the environment, especially the
sense of vision.
An elementary form of radar consists of a transmitting antenna emitting electromagnetic radiation
generated by an oscillator of some sort, a receiving antenna, and an energy-detecting device, or receiver.
A portion of the transmitted signal is intercepted by a reflecting object (target) and is reradiated in all directions. It is the energy reradiated in the back direction that is of prime interest to the radar. The
receiving antenna collects the returned energy and delivers it to a receiver, where it is processed to detect
the presence of the target and to extract its location and relative velocity.
The distance to the target is determined by measuring the time taken for the radar signal to travel
to the target and back. The direction, or angular position, of the target may be determined from the
direction of arrival of the reflected wave- front. The usual method of measuring the direction of arrival is
with narrow antenna beams. If relative motion exists between target and radar, the shift in the carrier
frequency of the reflected wave (Doppler Effect) is a measure of the target's relative (radial) velocity and
may be used to distinguish moving targets from stationary objects. In radars which continuously track the
movement of a target, a continuous indication of the rate of change of target position is also available.
1.2 History Background
James Clerk Maxwell (1831 –1879) - predicted the existence of radio waves in his theory of
electromagnetism. In 1886, Hertz experimentally tested the theories of Maxwell and
demonstrated the similarity between radio and light waves. Hertz showed that radio waves could
be reflected itself. Heinrich Hertz, in 1886, experimentally tested the theories of Maxwell and
demonstrated the similarity between radio and light waves. Hertz showed that radio waves could be
reflected by metallic and dielectric bodies. Due to these reflections occurred through metallic bodie
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