1. 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
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coined in 1940 by the United States Navy as an acronym for RAdio Detection And Ranging. The
term radar has since entered English and other languages as the common noun radar, losing all
capitalization.
The modern uses of radar are highly diverse, including air traffic control, radar astronomy, air-defense
systems, antimissile systems;marine radars to locate landmarks and other ships; aircraft anticollision
systems; ocean surveillance systems, outer space surveillance
and rendezvous systems; meteorological precipitation monitoring; altimetry and flight control
systems; guided missile target locating systems; and ground-penetrating radar for geological
observations. High tech radar systems are associated with digital signal processingand are capable of
extracting useful inform ation from very high noise levels.
Working of Radar
The modern uses of radar are highly diverse, including air antimissile systems, radar astronomy,
traffic control, air-defense systems; nautical radars to locate landmarks and other ships; aircraft anti-
collision systems; ocean-surveillance systems, outer-space surveillance and rendezvous systems;
meteorological precipitation monitoring; altimetry and flight-control systems; guided-missile target-
locating systems; and ground-penetrating radar geological observations.

2. About Radar
Visualize as early as 1880 by Heinrich Hertz and Observed that radio waves could be reflected off
metal objects. Radio help to Detection And Ranging
1930s Britain built the first ground-based early warning system called Chain Home.
1940 Invention of the magnetron permits high power transmission at high frequency, thus making
airborne radar possible.
Currently Radar is the primary sensor on nearly all military aircraft. Roles include airborne early
warning, target acquisition, target tracking, target illumination, ground mapping, collision avoidance,
altimeter, weather warning and gives Practical frequency range 100MHz-100GHz.
Working
The term “radio” refers to the use of electromagnetic waves with wavelengths so-called radio wave
portion of the spectrum, which covers a wide range from 104 km to 1 cm. Radar systems typically
use wavelengths on the order of 10 cm, corresponding to frequencies of about 3 GHz. The
detection and ranging part of the acronym is accomplished by timing the delay between transmission
of a pulse of radio energy and its subsequent return. If the time delay is Dt, then the range
may be determined by the simple formula: R = cDt/2. where c = 3 x 108 m/s, the speed of
light at which all electromagnetic waves propagate. The factor of two in the formula comes from the
observation that the radar pulse must travel to the target and back before detection, or twice the
range.

3. Two Principle of Radar
Pulse Transmission is a transmitter for transmitting power wirelessly to a receiver to power a load
comprises a pulse generator for producing pulses of power. The transmitter comprises a power sensor
which can sense when other transmitters are transmitting in order for the generator to transmit the
pulses at the appropriate distance.
Pulse Radar design
Continuous Wave

4. Is a constant amplitude and frequency of electromagnetic signal, Information is carried in the
unstable period of the on and off periods of the signal, for example by Morse code in early radio. In
early wireless telegraphy radio transmission, Continuous Wave waves were also known as
“undamped waves”, to distinguish this method from damped wave transmission.
Types and usage of Radar
— Navigational radars are like search radar, but use short waves that reflect off hard surfaces. They
are used on commercial ships and long-distance commercial aircraft
— Mapping radar scans a large regions for remote sensing and geography applications
— Air traffic control uses radar to reflect echoes off of aircraft
— Weather radar uses radar to reflect echoes off of clouds
— Wearable radar which is used to help the visually impaired
— Search radars scan a large area with pulses of short radio waves
— Targeting radars use the same principle but scan a smaller area more often