Can the combination of THAAD and Patriot counter the J-20?

Source: Looking at the Sky

Recently, there has been a lot of activity around the THAAD anti missile base located in Seongju gun, Gyeongsangbuk do, South Korea. On the one hand, large trucks transporting construction materials frequently enter and exit. On the other hand, more than 100 South Korean citizen groups and local residents who oppose "THAAD's entry into South Korea" have been sitting in protest on nearby roads since 6am on June 22, and the police have forcibly driven them away. So, what shady things are being done inside the 'THAAD' base? In fact, the US military stationed in South Korea is implementing a project that not only builds basic living facilities and positions within the THAAD base, but also attempts to effectively integrate THAAD and Patriots in combat. After the successful merger of THAAD and Patriot, not only will the anti missile capabilities of both, especially the Patriot anti missile system, be significantly enhanced, but the anti stealth combat capabilities of the US military stationed in South Korea will also be strengthened. This poses a significant challenge for us.

Commander Daniel Kabler of the US Army Missile Defense Command stated in a written report submitted to the US Senate Armed Services Committee on June 9th that the integration of the THAAD missile defense system and Patriot system by the US military stationed in South Korea will end this summer. The main move for the combination of THAAD and Patriot is to have THAAD's AN/TPY-2 radar guide Patriot's interceptors. In theory, there is no problem with using THAAD's AN/TPY-2 radar to control the launch of Patriot missiles through technological improvements. The TPY-2 radar operates in the X-band and has a larger array, so its detection range and accuracy are much higher than the MPQ-53 and MPQ-63 radars of the Patriot. This backward compatibility is not a problem. Moreover, these radars were developed by the American company "Thor", and there are not many technical barriers between them.

However, to enable the radar of the THAAD system to control the interception missile of the Patriot system, it is necessary to integrate both hardware and software components. Because the Patriot radar uses the C-band, while the THAAD radar uses the X-band, it is necessary to install a data link or command receiving device compatible with the THAAD system for the Patriot interceptor missile. At the same time, it is necessary to establish a connection between the Patriot launch system and the THAAD command and control system. The second one is that the software needs to be upgraded. Because although the guidance process of the THAAD and Patriot-3 is roughly the same, for the radar, it needs to complete the initial and intermediate guidance. However, the specific working sequence of the two systems is quite different, and adjustments need to be made to the software system.

According to foreign media reports, a report from the US government shows that the Missile Defense Agency conducted two anti missile tests in 2020, using the AN/TPY-2 radar of the THAAD anti missile system to launch and guide the Patriot anti missile system interceptor missile. However, due to software issues, both tests were unsuccessful. However, these two failed test launches are not a major issue in terms of engineering development, it's just that there are still some software design problems. From the working systems of these two systems and the technical reserves of "Thor", it can be seen that the integration of "THAAD" and "Patriot" has not encountered any technical obstacles.

So, what advantages does achieving this' integration 'have for the US military? Firstly, it is certain that the anti missile capability has improved. The radar detection range and accuracy of the THAAD system are higher than those of the Patriot system, and can provide information support to the Patriot system's radar. Moreover, the THAAD system can use remote launch mode to launch missiles of the Patriot system, which can evenly distribute the Patriot's launch devices and cover more airspace. After the complete integration of the THAAD and Patriot systems in the future, it will be possible to achieve all-round multi-layer interception at altitudes ranging from 20 kilometers to 150 kilometers.

In fact, what many people overlook is that the combination of THAAD and Patriot will greatly enhance the US military's anti stealth capabilities. The current Patriot series air defense systems are difficult to effectively counter stealth operations due to their close radar detection range. It is possible that stealth aircraft may have launched missiles to attack them before being detected by the Patriot air defense system. Why can't the THAAD system intercept stealth aircraft? Because its interceptor missile is designed to intercept high-altitude ballistic missiles and uses an infrared imaging seeker. At altitudes below 40 kilometers, it is difficult to work effectively due to thermal background noise. That is to say, missiles cannot intercept targets below an altitude of 40 kilometers. But after the combination of the two, the "THAAD" system and the "Patriot" system are seamlessly connected. Due to the high power of the X-band radar in the THAAD system and its ability to detect targets with low radar reflection areas for thousands of kilometers, using this radar to guide Patriot air defense missiles can pose a significant threat to stealth aircraft.

Someone may have said that this is clearly aimed at China. Actually, there's no need to worry too much. On the one hand, although there have been setbacks in China South Korea relations, they are relatively stable. Some time ago, although South Korea also participated in the G7 Summit and followed the Americans, it was still able to recognize the consequences of side elections. When Moon Jae-in visited China in October 2017, the South Korean government made a "three no commitment" to China, that is, it would not allow the "Thad" system to be deployed, the South Korea would not join the US led anti missile system, and would not develop the South Korea US Japan military alliance.

On the other hand, although the combination of the THAAD system and the Patriot system has greatly improved their performance, the key to this improvement is still the AN/TPY-2 radar of the THAAD system. This radar has poor maneuverability and targets are very large, making it difficult to achieve effective detection of low altitude targets. Overall, high-end competitors can still eliminate it through the comprehensive use of various means. At present, South Korea only has one "THAAD" system. Once this radar system is paralyzed, not only will the "THAAD" system fail to work, but the "Patriot" system will also be unable to be empowered and immediately revert back to its original form.