Character Introduction
has been studying at the University of San Andrew, after teaching at Dan Di University. I have been engaged in exploration of thunder rainstorm, in 1935, during the operation of the National Physics Laboratory Radio, he began working in aircraft radio positioning. It was already positioned at 112 kilometers from the 112-kilometer plane. The method is to launch radio beams to the aircraft, and then The radio waves reflected by the aircraft are received and the distance is calculated by the time consuming. This result made him the world's first practical radar system and became the decisive factor in the 1940 Britain's anti-Germany. His other contribution is: cathode ray probe for research atmospheric phenomena; research on electromagnetic radiation; some inventions for flight safety.
Main contribution
Robert Watson-Watt, 1892-1973) British scientists served as Director of the British National Physical Laboratory Radio Research Office, 1930s At the beginning, he used to use the radio wave detection ionization layer. The radar will begin again. Winning a big work in the British Battle.
Robert A. Watson-Watt and A.f. Wilkins In 1932, Watson-Watt suddenly had an idea of radio direction. Later, he and A.f. Wilkins were written in detail the radio detection and corrected, with radar. In order to get funding, two people conducted the first demonstration in the UK. With the transfer of DAVENTRY BBC short-wave broadcasting station, they measured the energy reflected from the bombers flying from the Heyford base to the bombers in different regions. The detection reached 8 miles.
During World War II, Watson Watt designed the world's first practical radar warning system, effectively fighting the air strikes in Nazi Germany. In April 1935, Robert Watson-Watt acquired a patent of the British air defense radar system. Many scientists and engineers have contributed to the development of radar systems in the Radar system of the Allied Army in the Second World War. Radar is the first-character thion of Radio Detec-Tion and Ranging by transmitting radio waves, and the signals reflected back to detect distant objects, such as aircraft or vessel. Robert Watson-Watt Jazz first develops a practical radar system, which is used to help defend against the UK during the Second World War, one of the greatest radar pioneers. The basic principles required by the radar system have been established in the 1980s, and the German physicist Heinrich Hertz initiates radio waves first, transmitting it in his laboratory.
Sorrow 300,000 yuan US dollar buryed Japan United Fleet
In the Second World War, the US Navy in the Pacific History The most tragic chapter. However, people may not know that small radars have an important impact on the victory of this war. The Japanese Navy missed the opportunity to have radar in the United States, and buried a film for eventually failure.
Near the Bai Cipild Airport, California, California, has a Ph.D., a named Spchior. He is an authority to be famous at home and abroad. After the World War I broke out, Sibic invented a device that captures aircraft position and route by transmitting radio waves, that is, radar. In order to promote its own invention, he negotiated with the US land navy and civil airlines, and offers 300,000 US dollars, but military and airlines are not interested. In desperation, Scarce turned his gaze to abroad. He found his own Japanese neighbors in the Valley doctor, hoping that China Valley would help sell the device to Japan. Sibic said to Zhonggu: "As long as there is this device, the plane can run at a glance in the air. If the plane falls, it can also know the location of the crash. This is essential for airlines. Please You contact Japan Airlines. "" "
Soon, the Tale of Technologists in Japan Navy Technology Research Institute, and gave radar reference book, some drawings and photos to Tian Dao . Tian Lao looked through the radar information, and realized that this invention will bring huge changes to the Japanese Navy. So he sent the information to the shipping department, I hope they can buy this invention. However, the researchers of the shipping department said: "Only from the two-point emission radio wave can determine the position of the aircraft, this method of transmitting electric waves is not good. Therefore, it is possible to pay $ 300,000, huge money to buy it, we The Navy is never allowed to do this. "
Tian Dao is refused to give up, and it will enter the aviation. The aviation part also said: "Whether this device can be manufactured, we also have questions. However, from the view, it is effective. If you can spend $ 100,000, it is good. "Subsequently, this thing is shelved by the aviation. One year later, in the Retidance of Tian Dao, the aviation this department finally agreed to spend $ 300,000 to buy radar. However, this radar device has been bought by the US military, and the Japanese people have passed with this new equipment. It turned out that the US essessment authority learned from the British military that as the secret weapon of the British army, radar played a huge role in the European battlefield, and the United States decided to have such a weapon as soon as possible. After buying the radar of Scarce, the US military has quickly transformed and installed in the warship.
After the Battle of the Midway, the US military launched a big counterattack. With the radar full equipment fleet, the US military has achieved more and more results. On October 11, 2002, the Japanese night attack of "Tokyo Express" was "Tokyo Express", the US army of Guadal Kanar is launched, so that the Japanese Navy of "Night War" did not expect that they have not found American ships. I was attacked by American ship's violent gunfire, the cruiser "Ancient Eagle" sank, the commander after the fight, the destroyer "blowing snow" is also sinking, only the cruiser "Blue Ye" is struggling to escape, "Tokyo Express "first tastes the fault. Since then, the Japanese warships often have been hit, especially the Japanese submarines, and in the evening, in the evening. Later, the Japanese army finally understood that it turned out to be a US army's radar found his fleet.
In the summer of 1944, the Japanese warship has finally installed radar, but it is too late, the Japanese Navy's kilometery is already ringing, facing the US radar advantage, Japanese people can't help but lament: "We The $ 300,000 is buried in the Empire Navy. (Source: "Global Times")
Radar Introduction
Defining Radar Concept is formed in the early 20th century. Radar is the transliteration of English Radar, meaning radio detection and ranging, is an electronic device using microwave band electromagnetic wave detection target. The specific uses and structures constituting various radars are not the same, but the basic form is consistent, including five basic components: transmitters, launch antennas, receivers, receive antennas, and displays. There are also auxiliary devices such as power supply, data admission devices, anti-interference equipment. The role and eyes of working principle radar, of course, it is no longer a masterpiece of nature, and its information carrier is radio waves. In fact, whether it is visible or radio waves, in essence is the same thing, it is electromagnetic wave, and the speed of propagation is light speed C, the difference is that their respective bands are different. The principle is that the transmitter of the radar device is reflected by the electromagnetic wave energy towards the space in this direction, and the radar antenna receives this reflected wave, sent to the receiving device for processing, and extracts Some of the objects (the distance between the target object to the radar, distance change rate or radial speed, orientation, height, etc.).
The measurement distance is actually measuring the time difference between the transmit pulses and the returning pulse, which is propagated by the electromagnetic wave, which can be converted into the precise distance of the target. The measurement target orientation is to measure the sharp orientation beam measurement of the antenna. The elevation beam measurement is measured by the narrow angle. The target height can be calculated according to the elevation and distance. The measurement speed is the frequency Doppler effect principle generated by the radar according to the relative motion between itself and the target. The target echo frequency received by the radar is different from the radar emission frequency, and the difference between the two is called Doppler frequency. One of the main information extracted from the Doppler frequency is the distance change rate between the radar and the target. When the target and interference clutch are present within the same space resolution unit of the radar, the radar uses the Doppler frequency of the Doppler frequency from the interference clutter to detect and track the target. The advantage of applying radar is that the night can detect long-distance goals in the daytime, and the barrier of fog, clouds and rain is all-weather, all day, and has certain penetration capabilities. Therefore, it is not only an indispensable electronic equipment, but also widely used in socio-economic development (such as meteorological forecast, resource detection, environmental monitoring, etc.) and scientific research (natural research, atmospheric physics, ionospheric structure research, etc.). Astronical and airborne synthetic aperture radar has become a very important sensor in today's remote sensing. Radars targeted with the ground can detect exact shapes in the ground. Its spatial resolution can reach a few meters to tens of meters, and it is independent of distance. Radars showed good application potential in flood monitoring, sea ice monitoring, soil humidity survey, forest resource investigation, geological investigation and other aspects.
Radar species
Radar variety, can be classified by multiple methods: (1) can be divided into: active radar, semi-active radar and passive radar. (2) The installation site can be divided into; ground radar, carrier radar, aviation radar, satellite radar, etc. (3) According to the type of radiation, it can be divided into: pulsed radar and continuous waverada. (4) According to the work, the long band can be score: Miparada, pivota, centimeter wave radar and other band radar. (5) According to the purpose, it can be divided into: target detection radar, reconnaissance radar, weapon control radar, flight guarantee radar, meteorological radar, navigation radar, etc. The phase-controlled radar is a new type of active electric scan array multi-function radar. It not only has functions of traditional radar, but also has other RF functions. The most important feature of the active electric scan array is to be able to radiate and receive radio frequency energy directly into the air. It has many significant advantages over the mechanical scanning antenna system.
Radar History
1842 Doppler (Christian andreas Doppler) took the lead in using Doppler radar using Doppler effect.
1864 Max Clerk Maxwell derived a formula that can calculate electromagnetic output. 1886 Heinerich Hertz launched a series of experiments to study radio waves. 1888 Hepz successfully produced radio waves. 1897 Thompson (JJ Thompson) launched the study of cathode rays in vacuum tubes. In 1904, Hristian Hülsmeyer Invention Electroscope, is a device that uses radio waves echo detection, which prevents the sea from collision. In 1906 DE FOREST LEE, Vacuum Triameter, is the active electronic component of the world's first enlargeable signal. In 1916, Marconi and Franklin began to study short-wave signal reflections.
1917 Watt Watson-Watt successfully designed a thunderstorm positioning device. In 1922, Marcni speaking at the American Institutes of Electrical and Radio Engineers, the topic is to prevent the plane of the vessel from colliding. In 1922, Taylor and Yang suggested in two warships to provide high-frequency transmitters and receivers to search for enemy ships. 1924 APRON and Barnet were reflected in the height of Ionosphere by ionospheric reflecting radio waves. The US Blair and Duff use pulse wave to measure the Hailor. In 1925, Bead (John L. Baird) invented a mobile TV (predecessor of modern TV). In 1925, Gregory Breit cooperated with Duwu, the first successful use of radar, and the radio short pulse reflected back from the ionization layer was displayed on the cathode ray tube. In 1931, the US Navy Research Laboratory used the shooting frequency principle to develop radar, and began to make the transmitter launch continuous wave, three years later, pulsed pulse waves.