Radar represents Radio Detection and Ranging. The term Radio alludes to the utilization of electromagnetic waves with wavelengths in the purported radio wave segment of the range, which covers a wide range from 104 km to 1 cm.
Radar is an electromagnetic framework for the identification and position of targets. It works by transmitting a specific type of waveform, for example, a sine wave or cosine wave, and identify the nature of receiving the reflected signal. By analyzing the reflected signal, the target can be located and sometimes identified. Radar is utilized to expand the ability of one’s faculties for watching the earth, particularly the feeling of vision. A basic type of radar containing a radio transmitting antenna, to transmitting the electromagnetic waves, a receiving antenna, which used to receive or catch the reflected waves and a signal analyzing section, which analyzes the received reflected waves. The radar transmits the electromagnetic energy pulse and reflected from the target. The small portion of the energy is reflected back and reached to the receiving antenna. The returned energy is called ECHO, just as it is in sound terminology. This echo is useful to identify the direction and the position of the target. The distance of the target is dictated by estimating the time taken for the radar echo to travel to the target and return back. The basic principle behind the operation of radar is Doppler Effect, which states that ” When wave energy like sound or radio waves travel from two objects, the wavelength can seem to be changed if one or both of them are moving. This is called the Doppler effect.”
History of Radar
In 1887 the German physicist Heinrich Hertz Began trying different things with radio waves in his research facility. He found that radio waves could be transmitted through some materials, and reflected by others. Some years later a German engineer, Christian Huelsmeyer, proposed the use of radio echos to avoid collisions in marine navigation. The invention of modern radar is generally credited to Sir Robert Waston-Watt. Nikola Tesla, in August 1917, first settled standards in regards to recurrence and power level for the main crude radar units. Prior to the Second World War, improvements by the Americans, the Germans, the French, the Soviets, and the British prompted the cutting edge rendition of the radar.
Working Principle of Radar
A radar setup has a transmitter that produces radio waves called radar signals in the direction of moving or stationary targets. When these radar signals strike or collide on the target surface, they will be reflected or dissipated in various directions. Radar signals are reflected properly by materials of significant electrical conductivity particularly by most metals, via seawater and by wet ground. A portion of these makes the utilization of radar altimeters conceivable. The radar signals that are reflected back towards the receiver are the essential ones for the working of radar. With the help of these reflected signals, it can be identified that the target is moving either towards or away from the radar, because there is an approximately equal change in the frequency of the reflected back signal, due to the Doppler effect.
The setup of the radar is given in the figure. An electromagnetic signal is transmitted by the transmitter and this transmitting signal is transmitted in space with the help of an antenna. Some portion of the transmitted signal is reflected back by the target surface towards the radar. After the analysis of this reflected signal the position, distance and direction of the targets can be identified. Due to this working system radar’s full form is radio detection and ranging.
Types of Radar
Basic Pulse Radar CW Radar FM-CW Radar MTI Radar
Application of Radar
Main applications of Radar are-
Military application – In the military, radars are used for surveillance purposes of the enemy aircraft. The surveillance radar detects, locate and identifies the enemy aircraft. It is also used for providing navigation aids to the military as well as civil aircraft.
Weather Radar – These radars use radio waves with horizontal, dual (horizontal and vertical) or circular polarization. Some weather radar uses the Doppler principle to measure wind speed.
Air Traffic Control – In ATC the radar is used at airports to identify all aircraft, they are either coming towards or going away to the airport.
Navigation Radar– This type of Radars used for navigation if ships in the sea or long-distance commercial aircraft in the air by transmitting short waves.
Police Radar – These types of Radars are used by police at the local level to identify the speed of different vehicles.