Radar

Presenter : Khizra Samad

• 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.

• 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.

Reasons of use

• 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.

How it works• 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.

Uses• 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.

cont..

• 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.

Reference• http://en.wikipedia.org/wiki/Radar• http://science.howstuffworks.com/radar1.htm• http://www.howstuffworks.com/radar.htm