1On February 25th, 935, Britain began its first practical radar experiment to defend against the attack of enemy planes from the mainland. The medium used at that time was the conventional radio wave with a wavelength of 50 meters emitted by BBC. On a truck equipped with receiving equipment in advance, the researchers saw the echo of the radio signal reflected by the plane on the display, so the radar was produced.
Radar uses extremely short radio waves for detection. Radar consists of transmitter, antenna, receiver and display. Because radio waves will be reflected when encountering obstacles, the radar will emit them according to this principle, and then use the receiving device to receive the reflected radio waves, thus determining the direction, distance and height of the target. At first, radar was mainly used in the military. During World War II, Britain established a radar defense network on the coastline. These early radars enabled the British to continuously and successfully fight against the destructive German air and submarine attacks.
Radar is called clairvoyance. In modern warfare, due to the progress of radar technology, the warring sides have already started air combat when they are dozens or even hundreds of kilometers apart and people can't see each other. This is a feature of modern air combat using radar over-the-horizon air combat.
Because of the working principle of radar itself, there is a blind spot to capture objects in the use of radar, which is also a successful example of using radar blind spot to sneak attack in war. In modern warfare, in order to avoid the surveillance of radar, the United States has made a stealth bomber, which can effectively disperse radar signals and prevent them from being discovered by conventional radar systems. It is precisely because of this relationship between spear and shield that scientists continue to explore and develop radars with higher resolution in this field.
With the continuous improvement of radar technology, radar is widely used in civil aviation control, topographic survey, meteorology, navigation and many other fields. Facing the increasingly crowded sky, it is very important to have a sophisticated radar monitoring system. Using radar equipment can be monitored day and night without being affected by the weather. Civil aviation controllers can directly obtain the position, altitude, navigation trajectory and other information of the aircraft through radar, and adjust the flight direction and altitude in time. In the scientific principle of radar application, there is phase motion between radar and target, and the frequency of echo signal has Doppler frequency shift. According to the principle of Doppler effect, its relative velocity can be obtained. This is also the working principle of the traffic police speed radar to measure the speed of the car on the expressway.
China has made great achievements in radar technology. Ground penetrating radar (GPR) is developed in China and can be used for underground detection at different depths. At present, ground penetrating radar has been widely used in national defense, urban construction, water conservancy, archaeology and other fields. The Institute of Electronics, Chinese Academy of Sciences has successfully developed a simulated prototype of spaceborne synthetic aperture radar, monitored the catastrophic floods in the middle and lower reaches of the Yangtze River from 65438 to 0998, and obtained the images of the affected areas, providing accurate disaster data for flood control and disaster relief. With the continuous development of high technology, radar technology