Radar Technology Boosts Detection of U.S. F-22 Stealth Jets by 60,000 Times!

According to a report from the South China Morning Post on April 18th, Chinese scientists have developed a stealth aircraft detection technology that can amplify extremely weak stealth aircraft signals by 60,000 times. Not only do U.S. F-22 and F-35 fighter jets have nowhere to hide, even the yet-to-be-deployed B-21 is left exposed!

Those following China’s advancements in stealth fighter detection should remember that Chinese scientists also developed a technology last year for detecting and locating stealth fighters in the infrared spectrum. This technology can locate targets the size of F-22s at distances approaching 300 kilometers. It’s hard to imagine, with such technological capabilities in China’s hands, that the U.S. Air Force isn’t essentially running naked in the Western Pacific!

The technology in question: How can it amplify stealth aircraft signals by 60,000 times?

The F-22 is currently one of the world’s top fifth-generation stealth fighters. According to information released by the U.S. military, its frontal Radar Cross Section (RCS) is only 1 square centimeter, equivalent to the reflection of a metal surface the size of a fingernail. By reducing the RCS area by 10 times and calculating a decrease in detection distance by more than half (2/5), the typical reflective area for fourth-generation aircraft is 3 to 5 square meters, resulting in a radar detection range of approximately 160 kilometers!

Using this proportionate calculation, a target with a reflective area of 0.5 square meters would only be detectable at 80 kilometers, 0.05 square meters at 40 kilometers, 0.005 square meters at 20 kilometers, and a target with an area of 0.0005 square meters (5 square centimeters) would only be detectable at 10 kilometers. A target with an area of 0.0001 square meters would be detectable at a distance of less than 10 kilometers!

This data is quite alarming because being detected at less than 10 kilometers is almost entering visual range. It’s already within the locking distance of infrared dogfight missiles under radar silence conditions. Simply put, theoretically, in a confrontation with the F-22, even if the F-22 does not activate its radar, it can still be locked onto by the opponent without detection and be shot down by the infrared dogfight missiles launched by the F-22. Isn’t that quite terrifying?

In light of this, the U.S. military has always touted the F-22 as the most powerful fighter in the world! However, according to the South China Morning Post, Chinese scientists published a paper in the latest issue of the “Journal of Beijing University of Aeronautics and Astronautics,” stating that researchers have found a detection method that can amplify the F-22’s radar reflection signal by 60,000 times. In other words, the equivalent RCS area exceeds 6 square meters. In terms of detection distance, this means the F-22 fighter can be detected at distances greater than 200 kilometers!

The South China Morning Post report states that this technology has a significant impact on the F-22. The reason is simple: Originally, the F-22’s stealth capability could allow it to launch missiles or deploy glide bombs when approaching the theater of operations. Even with AWACS support on the battlefield, the F-22 could carry glide bombs with a gliding distance of over 130 kilometers and deploy them at a safe distance. However, after being detected at a distance of 200 kilometers, it becomes very dangerous because in modern warfare, from detection to locking on to being shot down, it’s basically a seamless process. The moment the F-22 is detected on the battlefield, who knows how many radars and missiles will be aimed at it!

Furthermore, the paper indicates that this new detection method can cover an area of approximately 63,000 square kilometers. Regardless of how the F-22 maneuvers, it cannot escape radar lock-on. Moreover, the positioning accuracy of this technology can reach an error of 20 meters in such a vast area. This level of precision can fully serve as fire control data for medium-range air-to-air missiles.

The maximum operational range of the PL-15 long-range air-to-air missile released by China is around 200 to 300 kilometers. With the F-22 detected at a distance of 200 kilometers, coupled with real-time updated data links, it becomes a “no escape zone.” According to the South China Morning Post, precise target coordinates and velocity calculations can be completed in just 0.008 seconds. Even if a fleet of F-22s intrudes, detailed data on each F-22 can be obtained within 0.2 seconds.

The data link will transmit this information to the fighter jets intercepting the F-22 and inject it into the inertial navigation data of air-to-air missiles. Subsequently, the missiles will be launched, ascend, and enter cruise mode. During flight, if there are significant changes in the data of the F-22 fleet, it will be immediately transmitted to the missiles via the data link. The onboard computer will adjust the missile’s flight trajectory based on the latest inertial navigation data, intercepting the F-22 at the preset position.

When the F-22 enters the “burn-through distance” of the missile’s active radar, the missile’s onboard radar will be activated and lock onto the F-22. In the face of highly maneuverable missiles, the powerful vector engines of the F-22 are futile. In this situation, the F-22 has no option other than being hit. This god’s-eye-view battlefield perception technology will exert tremendous pressure on the U.S. stealth fighters. Of course, it’s even more daunting for the F-35, which is inferior in stealth and maneuverability to the F-22.

What exactly is this technology? How does it perceive the F-22 with a “god’s-eye view”?

According to the South China Morning Post, this technology maximizes the use of existing equipment, and its principle doesn’t seem overly complex:

Multiple radar manufacturers in China have developed anti-stealth radars. These radars use various techniques such as emitting low-frequency electromagnetic waves or increasing transmission power to detect stealthy targets. However, these radars are usually designed to operate independently. Although they can detect targets like the F-22 and F-35, during the flight of the fighter jets, there are changes in posture, such as maneuvering flight, lateral flight, or even descending to a certain altitude, all of which can affect the quality of the echoes received. This can result in unstable echoes obtained by anti-stealth radars, leading to the loss of targets or the inability to track them continuously in many situations!

However, the paper published in the “Journal of Beijing University of Aeronautics and Astronautics” indicates that scientists have found a way to assemble multiple radars in the theater into an array, scanning the battlefield from different angles. Through a complex signal processing system, echo signals are “superimposed” and displayed dynamically on the battlefield. Because the battlefield is observed from multiple angles, F-22 or F-35 targets will not be lost under most maneuvering conditions and can be tracked steadily for long periods.

The paper states that this is not a new technology. Previously, experts attempted to integrate multiple radars in the theater into a “true array” to observe the battlefield. However, due to signal processing issues, it was difficult to perfectly superimpose them together, resulting in awkward scenarios of multiple batches of target warnings, i.e., the product of the number of targets and the number of radars. However, the research team’s latest signal processing technology and theater radar coordination technology have perfectly solved this problem:

The team has developed a groundbreaking “intelligent resource scheduling” method, allowing the centralized networked radar system to adjust beam parameters and the power of each radar according to the characteristics of stealth aircraft in the theater and their real-time positional changes. This ensures perfect coordination between signal processing and radar power.

What’s even better is that this technology doesn’t require radars to tilt all resources toward detecting stealth targets like the F-22. Instead, it only needs to allocate a portion of the time and power toward the areas where the F-22 might appear. Furthermore, this function doesn’t affect the radar’s detection in other directions. In simple terms, in the case of multiple radars working together, participating radars only need to “part-time.” The paper indicates that a minimum of only three radars is required to achieve comprehensive and stable tracking of an F-22 fighter formation. Of course, increasing the number of participating radars can improve resolution, positioning accuracy, and more stable tracking.

Moreover, this technology doesn’t place high demands on the radar and can come from land-based radars or radars on islands, or even from radars on ships and airborne early warning aircraft. This technology integrates radar in a certain area into a larger warning system, including information from airborne early warning aircraft, enabling true god’s-eye view observation of the battlefield. This technology is truly impressive!

Infrared detection: Passive detection technology, being locked onto without detection

On August 23, 2022, the South China Morning Post reported on the development of a new type of infrared detection technology by a team of Chinese scientists. It can detect the infrared signals of high-speed aircraft beyond the detection range of phased array radars! According to the report, engineers from China’s defense industry published a paper in the journal “Infrared and Laser Engineering,” stating that mid-wave infrared systems can now detect and track civilian aircraft within a range of 285 kilometers (177 miles):

“Target outlines, rotors, tails, and the number of engines can be clearly identified from the infrared spectrum image.”

Most infrared perception detection systems find it difficult to exceed a range of 20 kilometers because mid-infrared waves are easily absorbed by the atmosphere. However, the research team found that there are some strong infrared signals in the mid-infrared band that can propagate to far distances through the air. However, achieving this kind of detection is difficult because the number of photons that penetrate the atmosphere and reach the detector is very small, making monitoring very challenging.

However, the report states that the research team has already used an advanced optical sensor that can effectively detect a very small number of photons. Previously, this technology had been applied to the Mozi satellite to detect single photons, but now this technology has transitioned from civilian to military use, becoming the cutting-edge technology in the field of infrared detection.

What’s even more remarkable is that if the image is not clear enough, a laser beam can be fired to enhance the number of target-reflected photons, making the image clearer. From the illustrations in the paper, a commercial aircraft flying at a distance of 285 kilometers can be observed to the extent of several windows. You can imagine how terrifying this is! Because locking onto a fighter jet doesn’t require such high resolution. Coordinates in a three-dimensional space, plus target signal features, are sufficient!

Furthermore, the research team also stated that this system structure is relatively small and can be installed on vehicles, fighter jets, or even satellites, making it very convenient to integrate into fighter jets. According to a report on Flightglobal.com, China’s J-20 was already able to receive infrared signals from American B-2 stealth bombers and F-22 fighters at distances of 150 and 110 kilometers respectively, and this data was released as early as 2015.

You can imagine that if this infrared observation technology is combined with radar array technology, the area in the Western Pacific is almost transparent to China. I wonder how brave the U.S. F-22 and F-35 fighters would be to stroll near China’s doorstep. It seems that the arrival of these fighters will only increase our interest in technological innovation!

Further reading: Is the B-21 still relevant?

On April 16th, during a hearing of the Senate Armed Services Committee, U.S. Air Force Chief of Staff David W. Allvin stated that the U.S. Air Force will not purchase more than 100 B-21 bombers. Previously, the U.S. Air Force Global Strike Command and various think tanks had stated that at least 225 to 250 B-21s were needed, but the U.S. Air Force insisted on purchasing no more than 100. In 2015, the demand for the B-21 was 80 to 100, which later increased to 100.

This is the latest news on the U.S. military’s new stealth bomber. The result of its first flight was announced by the U.S. military as entering mass production within months. This shows the degree of satisfaction the U.S. military has with this stealth fighter. The B-21 is a highly anticipated bomber for the U.S. military. It made its debut on December 2nd last year at Northrop Grumman’s facility in Palmdale, California. It is slightly smaller than the B-2 but has a comparable range. It’s speculated that the B-21 can fly 4,000 kilometers without refueling. Additionally, the B-21 can control “loyal wingmen” and its speed is said to be high subsonic. Although its speed is not faster than the B-2, its stealth capability is expected to be superior.

From the positioning of the B-21, the U.S. military hopes it will perform penetrative combat missions. Simply put, this bomber will arrive at China’s coastal areas or even enter inland areas to execute missions against anti-access systems. This was the pattern used by the B-2 bomber in South America, Iraq, and Afghanistan in the past. Now, the U.S. military actually intends to transfer this pattern to China, which is simply impossible!

Even if China doesn’t have such advanced detection capabilities, it’s practically impossible for the B-21 to penetrate the air defense network in the densely monitored southeastern coastal areas. Now with the technology of observing the battlefield from a god’s-eye view and passively detecting stealth fighters at 300 kilometers away, this battlefield is practically transparent to China. How else can this battle be fought? It’s like sneaking into someone’s house in disguise wanting to play big, but it turns out that the cameras installed in the house are broadcasting live.

Reference: https://www.scmp.com/news/china/science/article/3259428/chinese-scientists-increase-f-22-fighter-jets-radar-signature-60000-times-new-detection-method-study?module=top_story&pgtype=subsection

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