As Lockheed and the US Air Force push to promote the F-35 in Germany at the Berlin Air Show, Eurofighter marketing director Raffael Klashke responded to journalists who questioned him about the lack of stealth of Typhoon, given favorites in the race to replace the German Tornado. According to him, " Stealth only represents 10% of a device's performance, and the Typhoon is higher in the remaining 90%.
In fact, if stealth is effective against “classic” radars, several technologies are being deployed to counter this advantage. The opportunity to take stock of these different technologies, their strengths and weaknesses, and their probable deployment schedules.
Today, we can identify 4 aircraft detection technologies capable of countering the stealth used on aircraft like the F22, F35, J20, J31 or Su57. It is :
- Low frequency radars:
This is the simplest solution and the quickest to implement. Radars that operate in the VHF and UHF bands, with a wavelength between 10 and 80 cm (i.e. a frequency between 300 MHz and 1 GHz), benefit from a very sensitive resonance phenomenon on certain parts of the stealth devices, like fins and fins. The precision of these radars is significantly lower than high frequency radars, which has long led to them being considered unsuitable for detection and fire control. However, today, with AESA radars, frequency variations in the same radiation, associated with computer processing capabilities, make it possible to overcome this problem. In any case, this is the argument put forward by the new Grumman E2-D Hawkeye, or its Chinese counterpart, the KJ600, both of which have an AESA radar in the UHF band. Thanks to modern data links, these devices can not only detect stealth devices and missiles, but direct surface-to-air or air-to-air missile fire against these vectors. Russia and China have also begun the deployment of low-frequency radar in their terrestrial detection chains, particularly for the Russian S-400.
- Passive detection radars
These radars use electromagnetic radiation linked to human activities, such as the GSM network or TNT, to detect aircraft and missiles, including stealth aircraft, which were not designed for this type of frequency. This solution is very effective, to the extent that the radar does not emit any radiation, and is therefore perfectly invisible to the radar warning detectors of combat aircraft, which are unaware of having been detected. However, it requires the presence of relatively dense human activities, which prohibits its use in sparsely populated areas, or on the oceans.
Many countries have research projects on the subject. China has already put on the market a passive radar based on this technology, and it appears that it has deployed a detection satellite also using radiation of human origin to detect aircraft and missiles.
- Quantum radars
Quantum radars are still experimental, and Canada has announced investing $2,7 billion to develop this technology. This still very experimental technology is based on the observation of a microwave photon linked by quantum entanglement to a second photon propelled towards the detection zone. If this nomadic photon encounters an obstacle, its trajectory and its state will be altered, leading to the same changes on its “witness” photon, making it possible to precisely detect, by bombardment, information on a target. Very promising, this technology will not be operational before the end of the next decade, but it will deal a decisive blow to currently known stealth technologies.
- electro-optical detection
Current radars, whether high or low frequency, all have the same weakness: it is possible to detect its emission at a distance much greater than its detection range. This is why warships and fighter jets very often do not use their radars actively, and simply detect the radiation of a potential adversary to determine its position. In this context, the identification of a target often relies on visual confirmation. This is where devices like OSF (Front Sector Optronics) Rafale brings an important advantage, because they are capable of identifying an aircraft or a ship several tens of kilometers away, with powerful multi-spectrum electro-optical cameras. This technology, however, has its own limitations, for example requiring low cloudiness to be effective. But a combat aircraft that does not have a high-performance electro-optical system, such as the F35, will undoubtedly be at a disadvantage at medium range against an opponent who is equipped with one, such as the Su-35.
We see, stealth is far from being an invisibility cloak making a device invulnerable. On the contrary, this technology is likely to quickly lose its operational interest. It is therefore a very relative argument when it comes to choosing an aircraft expected to operate for several decades in an air force.