The radar known as "clairvoyance" is one of the most important electronic devices in modern warfare. This is a new invention in World War II. The word "radar" is translated from the English abbreviation radar, which means "radio detection and positioning". Radar can play an important role in military, meteorology, navigation and other fields. The basic principle of its work is to use the characteristics that electromagnetic waves will reflect back like echoes when they meet objects. When the radar system emits electromagnetic waves into space, some of them will be reflected back when they encounter objects, forming reflected echoes and reflecting them to the radar indicator. Through measurement and calculation, observers can detect distant targets and accurately determine the orientation, speed and distance of the targets.
As early as 1887, after the German scientist Henrich Rudolf Hertz confirmed the existence of electromagnetic waves, the scientific literature often mentioned the problem of using electromagnetic waves to detect targets. 1897, Russian physicist popov observed the phenomenon that electromagnetic waves were reflected by ships in his experiments, and proposed that this phenomenon could be used for military detection (such as detecting enemy ships). However, his suggestion failed to attract the attention of relevant departments. It was not until Italian engineer Marconi published a paper in 1922 that the US Naval Research Office verified this idea through experiments and developed a continuous wave radar with independent transceiver.
From 1925, the United States began to study the use of pulse modulation technology as a means to detect the distance of the target. 1935 15 in February, Britain first started to build the first aircraft radar station, and began the practical development stage of radar technology. 1in April, 936, the United States successfully developed the first pulse radar device with a detection distance of 4 kilometers. By 1938, the anti-air raid radar developed by the United States has been put into practical use.
In 1930s, Britain, France, Germany and the United States made great efforts to develop radar, among which the research work in Britain, Germany and the United States had a clear military purpose. At first, France only used radar for ships to detect icebergs, but when war was imminent, they quickly turned the practical application of radar to militarization. Germany first began to study the radar detection system of ships, and soon developed the radar detection system of aircraft. 1939 had an early radar warning system for invading aircraft, and then there was a radar warning system for ships. By about 1945, the Germans have been able to accurately guide anti-aircraft guns to shoot targets by using radar systems.
In World War II, radar really played the role of "clairvoyance" in national defense. 1940, in the air war between Britain and Germany, the radar wireless network saved Britain from extinction; A year later, Pearl Harbor became a sea of fire because the allied commanders ignored the plane signals of the Japanese attack on the radar screen. Also in World War II, British and American scientists developed a microwave airborne radar with higher precision and smaller volume, which gave allied pilots an obvious advantage in the air battle against Germany.
After World War II, scientists began to try to apply radar to scientific research. 1946, the United States successfully detected the radar signal reflected by the moon. In addition, radar can also be used as a navigation tool, or as a routine monitoring means to prevent the collision between ships and planes. The police use it to measure the speed of cars.
The appearance of high-speed aircraft puts forward new requirements for radar equipment and application technology. Obviously, the combination of computer and radar can solve the problem of radar automatic reconnaissance, that is, people use radar to detect aircraft attacks from all directions and send the detected signals to the computer in time, so that the computer can quickly decide what aircraft to dispatch to complete the interception task. After the successful development of the intercontinental missile, the radar meets the needs of the defense side to alarm as soon as possible. It can help the computer quickly determine the missile's flight trajectory, attack target and arrival time. For the invading intercontinental missile, the alarm can be given at least 15 minutes before the missile hits the target.
In 1960s, radar played an important role in the aerospace industry. For example, in human landing on the moon, spacecraft docking and other activities, radar cooperates with computers to complete many arduous tasks such as tracking and positioning. At the same time, radar is also closely related to basic disciplines such as mathematics, physics and biology, as well as space science and technology, medical technology and many other fields.
The development of science is endless. It is precisely because of the close flesh-and-blood relationship with all aspects of human society that radar electronic technology has strong vitality and is constantly developing in an increasingly broad scope.