According to the US Air Force Air Combat Command, on February 9th, the AN/ASG-34 Legion infrared search system pod, developed by Lockheed Martin and first equipped on the US Air Force F-15C fighter jet, has officially formed combat capabilities. The US Air Force regards this type of infrared search system as a so-called "game changer" and believes that the system will give the US Air Force's active third-generation fighter jets the ability to detect and strike opponent's fourth generation fighter jets.

The performance of the Legion pod is indeed commendable, but it does not mean that it can strike stealth fighter jets. After all, in terms of design principles, the principle of the "Legion" pod does not exceed the electro-optical radar equipped on the Su-27 fighter jet. It still detects the infrared characteristics of aerial targets, calibrates the opponent's targets, and achieves aerial situational awareness; This type of system is not uncommon in the air forces of major military powers, except for the Russian Air Force. For example, the FSO front sector optical system equipped on the French Air Force's Rafale fighter jet is actually a highly integrated electro-optical detection device with performance similar to the "Legion" pod.

Of course, the Legion pod also has its own unique skills. According to the testing of the Legion pod by the US Air Force in September last year, it seems that the US Air Force used the Legion pod to launch an AIM-120 medium range guided air-to-air missile. Before launch, the US military first used the "Legion" pod to conduct single site multi batch data collection on airborne targets. Combined with intelligent image recognition algorithms and other technologies, the azimuth and distance between the target and the aircraft were estimated, and the motion relationship between the target and the aircraft was simultaneously solved to generate fire control data, successfully guiding the AIM-120 missile to hit the target. This means that compared to the old-fashioned electro-optical radar equipped on the Russian Aerospace Forces' Su-27 fighter jet, which can only measure direction but cannot measure distance, or has a long distance and insufficient measurement accuracy, the US military's "Legion" pod is one generation ahead and has the ability to silently attack at medium range.

Although the test results of the US Air Force show that they are generous in praising the Legion pod, sometimes saying it is a "rule changer" and sometimes saying it can strike stealth fighters, Ivan the Great believes that with the current performance of the Legion pod, it is clearly a bit excessive to strike stealth fighters. Firstly, according to the US Air Force's own calculations, it is believed that under favorable weather conditions and testing conditions on the test field, the Legion pod can detect low detectable targets at a distance of only 20 to 30 nautical miles. This data is slightly better than typical planar slot array fire control radar, but it is equivalent to active phased array fire control radar. The only advantage is that it does not need to escape outward. Electromagnetic waves will not be countered by the opponent's ESM system, allowing for covert attacks.

The second issue is the testing of the "Legion" pod by the US Air Force in September last year. Although the "Legion" pod can generate fire control data, the AIM-120 missile still needs to use fire control radar to illuminate the target after launch, and use continuous wave irradiators or data links to perform mid course correction on the missile. This means that the beyond visual range attack of the "Legion" pod is actually a "pseudo" beyond visual range silent attack, as it also requires radar to "see" the target, which will pose significant obstacles to the use of this type of pod.The existence of the "Legion" pod at best marks that the US Air Force has finally figured out how to equip electro-optical radar after more than a decade of twists and turns. However, for this type of passive infrared detection system to truly pose a threat to stealth fighter jets, it must at least ensure that the situational awareness range is extended to 50 or even 60 nautical miles, which currently no electro-optical or infrared detection system can achieve.