College Of Engineering
How does radar work?
Dr. Majidah Hameed Majeed
Radar is the only way to see at night using high-frequency radio waves. The radar was used to start the discovery of enemy aircraft in World War II, and then expanded its use areas from the tool used by the police officer to control the fast cars to the devices used in the meteorological.
From the inventor?
Many scientists participated in the development of radar, but it was introduced into the field of war is the Scottish physicist Robert Watensen Wat (1892-1973), when he was working at the British Meteorological Center to monitor storms, and when World War II intensified in Europe, Electromagnetic waves in the detection of aircraft and ships, then he and his assistant Arnold Wilkins in the development of a technique capable of detecting the objects of counting and approaching from cities. The first was create a radar monitoring and tracking station on the south-east coast of the British Kingdom, which was credited with early detection and warning of German planes that were descending from the British coast. A radar station was built in the naval battleships in Pearl Harbor, Hawaii, but they did not discover the Japanese planes that blew themselves up in the fleet until very late.
What is radar?
During the day, the need for a lamp that generates a beam of light falls on the objects, so that the waves that bounce back to the eye will be reflected. The mind will immediately process and interpret the objects, and then we will not be able to collide with them.
The radar of the aircraft is somewhat like a lamp but uses radio waves instead of light. The radar in the plane sends an intermittent packet of waves at a specified time and hears that beam is reflected from objects near the remaining time and when determining the reflections, the master can identify the objects approaching it and knows the distance from them by processing the time of the reflection back and forth. In other words, the radar system is somewhat similar to the echo tracking system used by weak-sighted bats to fly in darkness.
If the radar is on a plane or a boat or anything else it must exist
• Tool for generating radio waves.
• A tool to send these waves away to the outside.
• Another tool to receive reflected waves.
• Processor that processes incoming information, interpreting it and then displaying it.
The radar valve sends the waves to a distance of several miles by the antenna, which is in the shape of a curve, which makes the waves sent in a narrow beam. In addition, the radar antenna can detect movements in a large area around it. Kilometers per second when collided with a body, part of which is reflected in a packet of reflected radio waves back to the antenna and reflected at the speed of light also. Since the radio waves are moving at the speed of light, there is no problem with the assumption that the enemy aircraft is at a distance of 160 km, radar can go back and less than a thousandth of a second.
The antenna can do two functions and rotate them through a piece called a "rotary switch". Radio waves taken across the antenna are directed towards an electronic piece that functions to process and display data meaningfully on the screen. The reception equipment distinguishes useless reflections coming from the ground and buildings. The important reflections are displayed on the screen, where the boats and planes are detected at high speed towards the observation station. Watching the radar screen looks like a video game (a green screen with dots), but dots on the screen represent real planes and ships.