Russia is famous for its air defense systems, but experts are debating how effective they are against stealth aircraft. A specialist in military technology writes about radar, which is not afraid of stealth technology. The author details the technical characteristics of the system and its disadvantages.
The National Interest (USA): Russia has one opportunity to detect and destroy low-profile F-22s and F-35s
It is possible to detect a subtle target, but it is very, very difficult.
After the advent of stealth technology for aircraft, many systems began to be widely advertised as “invisible killers”. One of the most innovative solutions is the Russian bistatic radar station Struna-1 / Barrier-E, developed by the Almaz-Antey group’s unit, NNIIRT. Almaz-Antey is the leading manufacturer of anti-aircraft missiles and radar in Russia. This he makes complexes “Buk,” “Thor” and S-400, as well as search radars for them. The Struna-1 radar was originally developed in 1999. In the future, this project developed, resulting in the Barrier-E station. This development, intended for export supplies, was demonstrated at MAKS-2007. It is not available in the online catalog of Almaz-Antey products, but it was shown along with other radars at the MAKS-2017 showroom. There are rumors that such radars are deployed around Moscow.
Struna-1 differs from most radars in that it is a bistatic radar. This means that the transmitter and receiver are located at different points, while at the usual radar station they are in one place. Conventional radars are limited by the specifics of radio waves. As the radar target is removed from the transmission source, the radar signal strength weakens in accordance with the reverse squares law. However, the radar detection system works by receiving a reflected signal. In conventional radar, this results in the received signal being four times weaker than the received signal. Stealth technologies work because the aircraft weakens the reflected signal at a distance, dissipating and absorbing it with special absorbent materials. The quality of radar tracking is deteriorating, making it much more difficult to obtain accurate information about the target.
In Struts-1, this problem is solved by the distribution of the receiver and transmitter to a certain distance. Because of this, the receiver receives a more powerful reflected signal compared to conventional radar, as it weakens in accordance with the law of reverse squares, rather than the reverse fourth force. Thus, the radar becomes more sensitive because it is now essentially a radar trap. According to Russian sources, this principle of work almost triples the effective target scattering area (EPR) and allows you to ignore anti-radar coatings that dissipate radio waves. This makes it possible to detect not only stealth aircraft, but also other aerial objects with low EPR, such as cruise missiles and hang gliders. One radar complex can include up to ten pairs of transmitter-receivers, which are called receiving posts (PPP) in Russian publications. There are different data on the layout of such posts, but the maximum distance between the two STIs can be as high as 50 kilometers. Thus, one radar theoretically covers a site with a perimeter of up to 500 kilometers.
These separate radar receiving posts consume quite a bit of electricity and have less radiation power than conventional radars. As a result, they are better protected from anti-radar weapons. The AFP are mobile, allowing them to be quickly transferred to the forward area during the conflict. They are connected with each other and with the central tracking station by ultra-high-frequency data channels. The central station can be located at a considerable distance from the complex. This spread architecture allows the complex to remain operational even if a single STIs is destroyed, although detection accuracy may be reduced. The low altitude of receivers and transmitter antenna antennas (only 25 meters above the ground) allows Strune-1 to detect low-flying targets very effectively, which are often difficult to detect conventional radar.