2. • Radar is an object detection system which uses radio
waves to determine the range, altitude, direction, or
speed of objects. It can be used to detect aircraft, ships,
spacecraft, guided missiles, motor vehicles, weather
formations, and terrain.
• The radar dish or antenna transmits pulses of radio
waves or microwaves which bounce off any object in their
path. The object returns a tiny part of the wave's energy
to a dish or antenna which is usually located at the same
site as the transmitter.
3. • Radar was secretly developed by several nations before
and during World War II. The term RADAR was coined in
1940 by the United States Navy as an acronym
for RAdio Detection And Ranging.
4. • When people use radar, they are usually trying to accomplish
one of three things:
1. Detect the presence of an object at a distance - Usually
the "something" is moving, like an airplane, but radar can
also be used to detect stationary objects buried
underground. In some cases, radar can identify an object as
well; for example, it can identify the type of aircraft it has
detected.
2. Detect the speed of an object - This is the reason why
police use radar.
3. Map something - The space shuttle and orbiting satellites
use something called Synthetic Aperture Radar to create
detailed topographic maps of the surface of planets and
moons.
5. • All three of these activities can be accomplished using
two things you may be familiar with from everyday
life: echo and Doppler shift. These two concepts are
easy to understand in the realm of sound because your
ears hear echo and Doppler shift every day. Radar
makes use of the same techniques using radio waves.
• Radar uses radio waves instead of sound. Radio waves
travel far, are invisible to humans and are easy to detect
even when they are faint.
6. •
•
•
•
•
•
•
•
•
•
Air traffic control
Radar astronomy
Air-defense systems
Antimissile systems;
Marine radars to locate landmarks and other ships
Ocean surveillance systems, outer space surveillance
systems
Flight control systems
Guided missile target locating systems
Ground-penetrating radar for geological observations.
High tech radar systems are associated with digital signal
processing and are capable of extracting useful
information from very high noise levels.
7. • weather surveillance radar (WSR) and Doppler
weather radar, is used to locate precipitation, calculate
its motion, and estimate its type (rain, snow, hail etc.),
intensity of the precipitation. It is used to determine the
structure of storms and their potential to cause severe
weather.
• Traditional
radar
sends
directional
pulses
of
electromagnetic energy and detects the presence,
position and motion of an object (such as an aircraft) by
analyzing the portion of the energy reflected from the
object back to the radar station.
• Imaging radar has been used to map the Earth, other
planets, asteroids, other celestial objects and to
categorize targets for military systems.
