The development history of radar

Radar was a major invention of human beings in the field of electronic engineering in the 20th century. The emergence of radar introduced modern scientific and technological means to mankind in many fields.

On February 25, 1935, the British began their first practical radar experiment in order to defend against the attacks of enemy aircraft on the local area. The media used at that time was a conventional radio wave of 50 meters wavelength transmitted by the BBC radio station. In a truck equipped with receiving equipment in advance, researchers saw the echo of the radio signal reflected by the aircraft on the display, and the radar was generated.

Radars use very short radio waves for detection. The components of the radar include transmitters, antennas, receivers and displays. Because radio waves are propagated, they can be reflected back when they encounter obstacles. The radar transmits the radio waves according to this principle, and then uses the receiving device to receive the reflected radio waves, so that the target's direction, distance, height, etc. can be measured. Initially, radar is mainly used in military affairs. During World War II, Britain built a radar defense network on the coastline. These early radars allowed the British to continuously and successfully fight against the German destructive air and seabed attacks.

Radar is called Clifford. In modern warfare, due to the advancement of radar technology, the two sides of the war are tens of kilometers or even hundreds of kilometers apart, and people cannot see each other, which has already opened the prelude to air combat. This is a feature of modern air combat using radar - beyond-visual air combat.

Due to the working principle of the radar itself, there are blind spots for radar to capture objects in use, which leads to successful examples of using radar blind spots to attack in war. In modern warfare, in order to avoid radar surveillance, the United States has produced a stealth bomber that can effectively disperse radar signals and keep it invisible to conventional radar systems. It is precisely because of this relationship between spear and shield that scientists have continuously explored and developed radars with higher resolution capabilities in this field.

Electronic equipment that uses microwave band electromagnetic waves to detect targets. Radar is the transliteration of radar in English, meaning radio detection and ranging. The concept of radar was formed in the early 20th century and developed rapidly before and after World War II. The working principle of radar is that the transmitter of the equipment emits electromagnetic wave energy into a certain direction of space through the antenna, and objects in this direction reflect the electromagnetic waves encountered. The radar antenna receives this reflected wave and sends it to the receiving device for processing to extract certain information about the object (distance from the target object to the radar, distance change rate or radial velocity, orientation, height, etc.). Radar is divided into two categories: continuous wave radar and pulse radar. Pulse radar is easy to achieve accurate ranging and the receiving echo is within the delay period of the transmission pulse, so the receiving antenna and the transmitting antenna can use the same sub-ante antenna, so it occupies a major position in the development of radar. The measurement distance is actually a measurement transmission

The time difference between the emitted pulse and the echo pulse is, because the electromagnetic wave propagates at the speed of light, can be converted into the precise distance of the target. The target azimuth is measured by the sharp azimuth beam of the antenna. The elevation angle is measured by a narrow elevation angle. The target height can be calculated based on the elevation angle and distance. When there is relative motion between the radar and the target, the target echo frequency received by the radar is different from the radar transmission frequency. The difference between the two is called the Doppler frequency. One of the main information that can be extracted from the Doppler frequency is the distance change rate between the radar and the target. When the target and the interfering clutter exist in the same spatial resolution unit of the radar at the same time, the radar uses the difference in Doppler frequencies between them to detect and track the target from the interfering clutter. The advantage of radar is that it can detect long-distance targets both day and night, and is not blocked by fog, clouds and rain. It has the characteristics of all-weather and all-day, and has certain penetration capabilities.

years

Major Events

1842

chrisdreas doppler took the lead in proposing a Dupler radar that utilizes the Dupler effect.

1864

Maxwell (james clerkell) derives formulas that can calculate the characteristics of electromagnetic waves.

1886

Heinerich hertz carried out a series of experiments studying radio waves.

1888

Hertz successfully used instruments to generate radio waves.

1897

Thompson Hompson) launched a study on cathode rays in vacuum tubes.

1904

chrishülsmeyer invented telemobiloscope, a device that uses radio wave echo detection to prevent collisions from ships at sea.

1906

Deforest (de forest lee) invented the vacuum transistor, which is the world's first active electronic component that can amplify signals.

1914

World War I broke out.

1916

Marconi and Franklin began to study shortwave signal reflection.

1917

Watson Watt (robers successfully designed the thunderstorm positioning device.

1922

Marconi delivered a speech at the American Society of Electrical and Radio Engineers, with the topic of planar angle radars that prevent ships from colliding.

1924

Sir Aprilton (sir edbsp;   1925

Baird (john l.baird) invented mobile TV (the predecessor of modern TV).

1925

Gregory Breit cooperated with Merley Tuve to successfully use radar for the first time to display short radio pulses reflected from the ionosphere on the cathode ray tube.

February 26, 1935

Watson Watt made its first practical radar device in Daventry, England.

December 1935

Marpany successfully designed and produced the launching curtain antenna array for installation in the world's first five chain-home radar stations. The effective range of these radars covers the estuary of the Thames River.

1937

Marconi added 20 chain-direction radar stations for the UK.

1937

The Varian brothers (russell and sigurd varian) have developed a high-power microwave vibrating device, also known as klystron.

1939

Butt (henry boot) and Johrandall) invented the electron tube, also known as resonance magnetron (resvityetr)

1944

Marconi successfully designed, developed and produced bagful systems and carpet radar jamming systems. The former is used to intercept German radio communications, while the latter is used to equip the RAF bomber fleet.

1945

At the end of World War II, the Allies were able to defeat Germany by relying on the radar equipped with a specially designed vacuum tube - magnetron.
Chapter completed!