Radar related knowledge

Radar means radio detection and positioning. Generally, it refers to electronic equipment that uses reflected electromagnetic waves to find targets and determine their positions. The main components are transmitter, antenna, receiver and display. It can be divided into pulse radar and continuous wave radar according to the working state. Widely used in reconnaissance, early warning, navigation, tracking, aiming, guidance and topographic survey, meteorological detection and so on.

The working principle of radar is: after the radar equipment sends out the electromagnetic wave signal, if the target object touches the radar signal, it will reflect back the echo, and the radar receiver will receive the echo signal, which contains the distance, direction and speed information of the target. After receiving the reflected wave, the radar antenna will send it to the receiving equipment for processing, extract some information of the object, and measure the angle of the target according to the beam emitted by the radar.

Radar is widely used in various fields of society, such as automobile reversing radar device. Radar is an auxiliary device for car parking safety. Automatically start the reversing radar when reversing, and you can know whether there are obstacles behind the car without looking back. It tells the driver about the obstacles around the car through sound or more intuitive display monitoring, which can make up for the driver's blind spots and blurred vision, and make parking and reversing easier and safer.

The radar is designed and developed according to the principle that bats fly at high speed in the dark without colliding with any obstacles. The advantage of radar is that it can detect long-distance targets day and night without being blocked by fog, clouds and rain. Can work all day and all day, and has certain penetration ability.

A radar device is installed on the bridge to constantly remind the driver how far the car is from the objects behind. When it reaches the dangerous distance, the buzzer starts to sound to remind the driver to get close to the obstacle and stop in time.

Radar, the transliteration of English radar, comes from the abbreviation of radio detection and ranging, which means "radio detection and ranging", that is, finding the target by radio and determining its spatial position. Therefore, radar is also called "radio positioning". Radar is an electronic device that uses electromagnetic waves to detect targets. The radar emits electromagnetic waves to illuminate the target and receives its echoes, thus obtaining information such as the distance from the target to the electromagnetic wave emission point, the rate of change of distance (radial speed), azimuth, altitude and so on.

The appearance of radar was due to the war between Britain and Germany during World War I, and Britain urgently needed a radar (technology) that could detect metal objects in the air and help search for German aircraft in anti-air strikes. During World War II, radar technology with the functions of ground-to-air, air-to-ground (search) bombing, air-to-air (interception) fire control and friend or foe identification appeared.

Various radars have different specific uses and structures, but their basic forms are the same, including transmitter, transmitting antenna, receiver, receiving antenna, processing part and display. There are also auxiliary equipment such as power supply equipment, data acquisition equipment and anti-interference equipment.

Radar functions like eyes and ears. Of course, it is no longer a masterpiece of nature, and its information carrier is radio waves. In fact, visible light and radio waves are essentially the same thing, both electromagnetic waves, and the propagation speed in vacuum is the speed of light C, the difference lies in their respective frequencies and wavelengths. Its principle is that the transmitter of radar equipment emits electromagnetic wave energy to a certain direction in space through an antenna, and the object in this direction reflects the electromagnetic wave it encounters; After receiving this reflected wave, the radar antenna sends it to the receiving equipment for processing, and extracts some information of the object (the distance from the target object to the radar, the change rate of distance or radial speed, azimuth, altitude, etc.). ).