When was the RADAR System created, and what is its purpose?
Radar was first developed during World War II to detect enemy planes, but it is now widely employed in everything from police speed-detector guns to weather forecasting.
What is the abbreviation for RADAR?
Radio Detection and Ranging
What is RADAR and how does it work?
Radars emit electromagnetic waves that are comparable to those sent out by wireless computer networks and cell phones. The signals are sent out in brief pulses that may be reflected by objects in their path, returning to the radar in part. Part of the energy is scattered back to the radar when these pulses intercept precipitation.
Is there an example?
Hearing an echo is akin to this concept. When you shout into a well, for example, the sound waves of your shout are reflected off the water and returned to you. The pulse reflects off precipitation and transmits a signal back to the radar in the same way. The radar can determine where precipitation is occurring and how much precipitation is there based on this information.
What are the most important features of RADAR?
A magnetron is a piece of equipment that produces the radio waves used by radar. The wavelength of radio waves utilised by radar is typically a few millimetres to a meter—the length of a finger to the length of your arm—roughly a million times longer than light waves.
The electromagnetic spectrum includes light and radio waves, which are made up of fluctuating patterns of electrical and magnetic energy zapping across the air. The waves produced by a magnetron are microwaves, comparable to those produced by a microwave oven. The difference is that a radar’s magnetron must send waves thousands of miles rather than just a few inches, thus it is much larger and more powerful.
After the radio waves have been generated, a transmitter antenna launches them into the air in front of it. The antenna is usually bent to focus the waves into a narrow, accurate beam, but radar antennas sometimes rotate to detect movement over a vast region. The radio waves move at the speed of light (186,000 miles or 300,000 kilometres per second) from the antenna and continue until they hit anything. Then, in a beam of reflected radio waves moving at the speed of light, some of them bounce back toward the antenna. The speed with which the waves travel is critical. When an enemy jet plane approaches at speeds of exceeding 3,000 km/h (2,000 mph), the radar beam must travel much faster to reach the plane, return to the transmitter, and activate the alarm in time. That’s not an issue because radio waves (and light) travel at speeds that allow them to travel seven times around the earth in a single second! A radar beam can travel 160 kilometres (100 miles) and back in less than a thousandth of a second if an enemy plane is 160 kilometres away.
The antenna functions as both a radar receiver and a transmitter. In fact, it switches between the two roles on a regular basis. It usually sends out radio waves for a few thousandths of a second, then listens for reflections for several seconds before broadcasting again. Any reflected radio waves picked up by the antenna are directed into an electrical device that processes and displays them in an intelligible format on a television-like screen, which is constantly monitored by a human operator. The receiving equipment filters out insignificant reflections from the ground, buildings, and other surfaces, leaving only major reflections on the screen. An operator can observe any nearby ships or planes, as well as where they are, how fast they’re travelling, and where they’re headed, using radar. Watching a radar screen is similar to playing a video game, but the specks on the screen represent real aeroplanes and ships, and the smallest error might result in the deaths of many people.
Methodology of RADAR System
- An energy pulse is generated by a transmitter.
- A transmit/receive switch that controls when the antenna transmits and receives pulses.
- An antenna for transmitting these pulses into the atmosphere and receiving the reflected pulses.
- A receiver for detecting, amplifying and converting received signals to video format.
- The signals that have been received are shown on a display system.
Reflectivity and velocity are the two main types of radar output. The amount of precipitation in a given area is measured by reflectivity. Velocity is a measurement of the precipitation’s speed and direction toward or away from the radar. Most radars can measure reflectivity, but to calculate velocity, you’ll need a Doppler radar.
What is the science behind RADAR?
Reflectivity
The physics of radar can be traced back to wave theory. In 1887, Heinrich Hertz, a German, discovered the behaviour of radio waves. He demonstrated that electromagnetic waves emitted by proper electrical circuits move at the speed of light and are reflected in the same manner. In the decades that followed, these qualities were utilised to calculate the height of the upper atmosphere’s reflecting layers. This is why the data from the radar is referred to as reflectivity.
Doppler
Christian Doppler, an Austrian physicist, had developed what is now known as the Doppler effect 40 years before, in 1842. This is the theory that when the frequency changes, the pitch of sound waves changes. An ambulance siren, for example, has a higher pitch when approaching but a lower pitch when leaving. Based on the shift in the siren’s frequency, you may calculate how fast the ambulance is going using Doppler’s theory. Doppler weather radar uses this idea to calculate the speed of precipitation in the atmosphere as it moves toward or away from the radar. Because precipitation moves with the wind as it falls, Doppler technology can be used to detect wind velocity.
What are the major applications of RADAR?
- Military Applications
- Traffic Management System
- Weather Forecasting
- Underwater Navigation etc
Fruitful Facts
Bats have a kind of Doppler radar. Their noses are able to emit a short ‘cry,’ which reflects off distant objects and returns as an echo to their ears. The bat can use this information to determine whether an animal is in its immediate proximity and whether that animal is travelling towards or away from it.
A prototype Hawaiian Radar detected the Japanese squadron that destroyed Pearl Harbour before the air strike, but no notice was sent since no one believed the rookie radar operators!
