This material is a continuation of the article on stealth aircraft "Knights of the Night Sky. From F-117 to F-35."
A lot is known about "black planes". Much less is known about the means of dealing with this scourge. A lot of ridiculous legends associated with the super-abilities of meter-range radars in detecting "invisibles" have become entrenched in the public consciousness. The main thing is that the frequency ranges of domestic radars are fundamentally different from those in which NATO radars operate. The adherents of this hypothesis are ardently convinced that the capabilities of radars and anti-aircraft missile systems of the 50s are sufficient to combat modern, inconspicuous aircraft. And of course, who is interested in tracking issues, methods of guidance and illumination of an air target or algorithms for its capture by the seeker of an anti-aircraft missile?
In the fight against alternative physics
The vast majority of modern radars used in air defense systems operate in the microwave range with wavelengths ranging from a few centimeters (X and C bands) to a couple of decimeters (S and L bands).
The loss of signal power increases with its frequency. Therefore, for long-range radars, it is preferable to work in the decimeter range of radio waves. It is no coincidence that this very range was chosen for the operation of the mighty S-400 (where the maximum detection range is 600 km) and for the Aegis naval air defense system, which is capable of shooting down targets in near-earth orbits.
Centimeter range radars are relatively compact. The small opening angle of the beam (only 1-2 °) allows them to scan a selected area of the sky with high resolution, making such a radar an indispensable tool for detecting high-speed small targets. The disadvantages of centimeter radars are high losses of radiation power, as well as the influence of atmospheric conditions on the operation of the radar (it is no coincidence that centimeter radars are used in meteorology to determine the properties of the atmosphere).
Multifunctional radar with a phased antenna array 91N6E - the main means of detection, tracking and control of anti-aircraft fire S-400 "Triumph". Works in the decimeter range (S).
Multifunctional radar AN / MPQ-53 of the American Patriot air defense system. Operates in the range with wavelengths of 5, 5 - 6, 7 cm (centimeter range C).
Multifunctional Aegis AN / SPY-1 radar installed on 104 cruisers and destroyers of the US Navy and its allies. The station uses the decimeter range (S) during operation.
The air defense facilities of the German frigate Sachsen-klasse provide two detection systems operating at different frequencies - the APAR horizon tracking radar (X centimeter band) and the SMART-L long-range radar (L decimeter band).
Antenna post of the SNR-125 missile detection and guidance station (part of the S-125 complex). The working range is centimeter.
There are no secrets here. The basic equation of radar, which determines the target detection range (the relationship between the generator power, antenna directivity, antenna area, receiver sensitivity and target RCS) is the same for all countries and armies of the world. The properties of radio waves of various bands are well known both to the creators of "stealth" and to those who create means of combating these machines.
The mysticism of meter waves
It is believed that all measures to reduce the visibility of aircraft lose their effectiveness when the aircraft is irradiated with meter waves. That radars operating at these frequencies are perfectly visible to "stealth", like other conventional aircraft. How true is this hypothesis and what is the basis for a bold statement about the "superpowers" of meter-band radars?
The meter range is the cradle of radar: it was in it that most radars worked at the dawn of radar technology. Alas, by now the majority of military radars have "switched" to decimeter and centimeter ranges. The reason is obvious - the antenna posts of the S and X-bands have radically smaller dimensions and, therefore, greater mobility. In addition, they allow you to form a "narrower" beam and give less error in determining the coordinates of an air target.
Due to their relative cheapness, long detection range and ease of operation, such systems are still used as surveillance radars in air traffic control systems in civil aviation, but their application in the military field is very limited.
In addition to the two-coordinate Soviet radar P-12 (1956), which until recently operated in the armies of a number of third world countries, meter-range radars are used as part of the domestic interspecific radar complex "Sky", as well as in the Belarusian radar "Vostok" (debuted at the MILEX-2007 exhibition).
Radar module of the meter range RLM-M of the 55Zh6M "Sky-M" complex
Means of the "Sky" radar - radars of meter, decimeter and centimeter ranges.
How do VHF radars become stealth killers? On this score, the supporters of this hypothesis do not give any logical arguments.
Objects, whose linear dimensions are much larger than the wavelength, reflect radio waves (in this case, the microwave range - meter, decimeter, centimeter) in the same way.
With regard to diffraction (wave bending around an obstacle), it is all the more pronounced if the linear dimensions of the obstacle are commensurate with the wavelength of the wave itself. How can this help to see stealth on VHF radar?
Finally, all of the radars listed are surveillance radars for air traffic control. Even being included in the air defense missile system, they will not be able to perform the functions of guiding anti-aircraft missiles, which inevitably require control on the cruising section and continuous "illumination" of the target at the terminal stage of flight. With the help of an additional ground-based fire control radar or the missile's own active seeker - one way or another, the guidance systems operate in the centimeter frequency range, where the highest target tracking accuracy is ensured.
How was the stealth shot down in Yugoslavia?
The F-117A Nighthawk superplane was knocked to the ground by an ordinary Soviet air defense system. An irrefutable fact!
If outdated complexes so easily shoot down modern "stealth", why weren't the Serbs able to show the remains of other "black aircraft"? A whole squadron of F-117A (12 vehicles) took part in the bombing of their cities, making 850 sorties over the territory of Yugoslavia.
This paradox has a simple logical and technical explanation:
Television optical sighting system "Karat-2" (9SH33). A standard missile guidance system for the S-125 air defense missile system, used in a difficult jamming environment.
The Serbian crew visually detected the stealth and aimed the missile at radio commands using optical fire control devices. Courage, professionalism and rare luck. This conclusion is confirmed by the words of the participants themselves. Zoltan Dani mentioned the French Phillips thermal imager (obviously, a home-made modernization of the air defense system). Pilot Dale Zelko said that his "Nighthawk" was shot down, barely breaking through the lower edge of the clouds.
Epilogue
Returning to the main message of today's article: why do domestic air defense systems of the S-300/400 family, like their American counterparts - the proven Aegis and Patriots still see stealth?
The answer is obvious - the radiation power and sensitivity of the antennas of modern radars are too high. So much so that not a single object larger than one "nanometer" can be unhindered in the zone of action of the new generation anti-aircraft systems.
Lockheed Martin designers are justly proud that the frontal F-35 fighter's RCS does not exceed 0.0015 m², which is the equivalent of a metal golf ball!
To which the engineers of BAE Systems (Great Britain) calmly answer that their latest SAMPSON radar is capable of detecting a flying pigeon from a distance of 100 km!
And it doesn't matter how much the performance characteristics of both systems were inflated in the advertising brochures of the companies. The main thing is that no one in their right mind and good memory will dare to "breastfeed" on modern air defense systems. The radar will still detect any intruder, and it will do so at a considerable distance - several tens of kilometers.
Nevertheless, "stealth technology" has a right to life. Reducing the aircraft's signature can play an important role in aerial combat. Where the capabilities of fighter airborne radars are incomparable with the "vigilance" of the 91N6E super-radar (S-400 "Triumph").
Finally, the shorter detection range of the "stealth", in comparison with a conventional aircraft, expands its "free maneuvering zone". With the development of modern guided and planning ammunition, letting the carrier aircraft even 100 km away means big problems for the defending side.
110-kg planning bombs GBU-39 SDB. Max. launch range 110 km, guidance methods - GPS + IR seeker.
In the background, the carrier - F-22 Raptor
