As stealth fighters continue to reduce their own radar reflection cross-section, using infrared systems to search for the infrared optical characteristics of stealth fighters has also become an effective anti-stealth method.

After the emergence of stealth fighters and stealth bombers, anti-stealth operations have become a technology focused on the development of the air forces of various countries. As stealth fighters continue to reduce their own radar reflection cross section (RCS), using infrared systems to search for the infrared optical characteristics of stealth fighters has also become an effective anti-stealth method. India's "Eurasia Times" quoted relevant reports from the "South China Morning Post" and reported on China's latest infrared search and tracking system.

Indian media stated that the Chinese military-related enterprise Sichuan Jiuzhou Electric Group published a paper in the Chinese journal "Infrared and Laser Engineering" stating that its infrared search and tracking system can travel 285 kilometers (the title of the article says 300 kilometers, but the content Accurately detect the infrared source of the aircraft at a distance of only 285 kilometers). Optoelectronic engineer Liu Zhihui said that this infrared search and tracking system can identify the target's outline, number of wings, tail and engines from infrared spectrum images. In addition, in addition to searching for the infrared optical characteristics of the aircraft, this infrared search and tracking system can also actively emit laser beam to illuminate the target to collect more detailed target information, such as the number of windows on the target aircraft.

The most important thing is that this infrared search and tracking system is not large and can be easily installed on cars, airplanes and even satellites. It can be used to build surveillance and early warning systems, and can also be used to provide corresponding guidance services for missiles .

Indian media stated that with the increase in the number of fifth-generation stealth fighter equipment and the expansion of the equipment scope, the infrared search and tracking system (IRST) has gradually become an urgently needed equipment for some fighter jets. Although the fifth-generation stealth fighter has only a small radar reflection cross section (RCS), IRST mainly tracks targets through the engine tail flame and the high temperature generated by the friction between the fighter and the air.

Although some fifth-generation stealth fighters, such as the American F-22 stealth fighter , choose to reduce their infrared optical characteristics by equipping them with a new "mirror coating", they still cannot escape IRST detection and locking. Moreover, the working mode of IRST is passive, which means that fighters equipped with IRST can fight fifth-generation stealth fighters with the airborne radar turned off, reducing the probability of being discovered and locked by fifth-generation stealth fighters.

Indian media stated that "Global Flight" reported as early as 2015 that China's J-20 stealth fighter has been equipped with an IRST system and can detect the US Air Force's B-2 stealth strategic bomber at a distance of 150 kilometers. The detection range of the US F-22 stealth fighter is 110 kilometers. If China's J-20 stealth fighter is equipped with this latest infrared search and tracking system, the detection range of the B-2 stealth strategic bomber and F-22 stealth fighter will be even further.

Especially the B-2 stealth strategic bomber, the safety of its entire aircraft depends entirely on the stealth advantage brought by its flying wing layout. The B-2 stealth bomber cannot carry out supersonic flight, nor can it maneuver through the air. To get rid of the attack of air-to-air missile . Once discovered by the J-20 stealth fighter through the infrared search and tracking system, the B-2 stealth bomber is almost a dead end, without any hope of escape.

Optoelectronic engineer Liu Zhihui said in the paper that it is very difficult to increase the range of infrared search and tracking systems. Because only a few photons can be captured by the observation lens of the infrared system. Their solution was to use the Single Photon Detector (SPD), which is capable of accurately detecting and observing single photons.

Indian media stated that although the Chinese research team did not mention the specific information of SPD. However, China has always been the world leader in this field. The "Mozi" satellite launched by China in 2016 was equipped with the most sensitive SPD at the time, and used it to achieve space quantum communication.

Engineer Liu Zhihui also stated in the paper that even if the detection distance of the system is increased, how to capture the infrared characteristics of fast-moving targets is still a very big problem. Because infrared radar must scan the sky for a long time to capture weak signals from distant targets, but the infrared signals left by high-speed moving targets are very weak and blurry. Eventually, they eliminated this blur by adding a mirror to the system that could rotate quickly to precisely and automatically adjust the beam.

currently. This system can search a considerable area of ​​​​airspace in a few seconds. This scanning efficiency has far exceeded most of the current infrared search and tracking systems in the world. Moreover, the entire system has good environmental adaptability and can still work normally in environments ranging from minus 40 degrees Celsius to above zero 60 degrees Celsius and capture corresponding infrared targets.

Indian media stated that this is not China’s only latest achievement in this field. Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences has also previously developed a long-range infrared radar, which is reported to be able to detect the infrared heat signals of modern aircraft at a distance of 225 kilometers. Even on a clear night, the system can observe the International Space Station more than 1,000 kilometers away.

The Indian media’s statements in some aspects are indeed in line with the current situation of fifth-generation stealth fighters. For example, the AN/ASQ-239 electronic warfare system equipped on the US F-35 stealth fighter has a powerful passive detection function and can detect the opponent’s aircraft according to the situation. The radar waves emitted by the radar are reflected back to the specific location of the radar emission source, and a counterattack is launched. But if the J-20 stealth fighter chooses to turn off the airborne fire control radar, and then uses the mounted EOTS and EODAS to lock and attack the infrared optical characteristics of the F-35 stealth fighter , then the F-35 stealth fighter will not know the J-20 stealth fighter. 20. Where did the stealth fighter launch its attack?

If China’s new infrared search and tracking system reported by the Indian media this time really has a detection range of about 285 kilometers and can be integrated into the J-20 stealth fighter, it will greatly enhance the J-20 stealth fighter’s effectiveness against the US military. Countermeasure capabilities of stealth fighter groups. Of course, in addition to stealth fighters such as , J-20 and J-35, the H-20 stealth bomber that has not yet entered service can also be equipped with this infrared search and tracking system to actively detect dangerous targets during missions and detect them in advance. To avoid.

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