One of the most debated topics in recent years are stealth technology. Despite the fact that the first aircraft with their application appeared more than 30 years ago, so far not subside controversy about their efficacy and practical utility. Each argument is pro and contra own as always happens. With all of this aviation industry advanced countries seem to make their own choices in favor of the introduction of stealth technology. With all of this, unlike the earliest projects, new aircraft are made taking into account the reduction of radar and thermal sight, but less. Now stealth is not an end in itself. As shown not very successful experience of operating the aircraft Lockheed F-117A, the cornerstone necessary to put aerodynamics and flying characteristics, not stealth. Because constructors radar and air defense systems are small «hook» to detect and attack stealth aircraft.
Despite the long history of research and development in the field of invisibility, the number of workable techniques and not so great. Thus, to reduce the probability of detection of aircraft using radar, he must have special hull shape and wing minimizes reflection radio transmitting antenna in the direction of, and, if ability to absorb part of this signal. In addition, thanks to the development of materials was made possible the introduction of radio-construction materials that do not reflect radio waves. As for stealth in the infrared spectrum in this region, all decisions can be counted on the fingers. More popular method is to create a special nozzle for the engine. Thanks to its own form of such unit is able to significantly cool the reactive gases. As a result, the introduction of at least some of the available methods of reducing visibility significantly decreases the detection range of the aircraft. With all of this total invisibility is unattainable in practice, can only be a decrease in the reflected signal or radiated heat.
Specifically residues radio and thermal radiation and are the «hooks» that can afford to find configured using stealth aircraft. In addition, there is a technique allowing to increment visibility stealth aircraft, without resorting to a complex technology solutions. For example, often encouraged to use their stealth aircraft against its main feature — the scattering of the incident radio waves. In theory can be diversity transmitter and receiver radar for quite a long distance. In this case, «distributed» radar will be able without much difficulty to capture the reflected radiation. However, despite its simplicity, such a method has a number of severe shortcomings. First, is the difficulty of ensuring efficiency radar separated by a significant distance transmitter and receiver. Requires a certain communication channel, connecting the various stations and components having sufficient properties of speed and reliability of data transmission. In addition, in this case special difficulties are caused by the great complexity or even the inability to do two spinning antenna, synchronize systems, etc.
All the difficulties of diversity radar equipment did not allow the use of such systems in practice. Yet, a similar principle is used in electronic intelligence systems, which can be used to detect enemy aircraft. Last year, the European concern EADS announced the development of the so-called passive radar, which works only for receiving and processing the signals. Principle acts of such a system is based on the reception of signals from foreign emitters — television and radio towers, substations, cellular, etc. Some of these signals may be reflected by soaring aircraft and enter the antenna passive radar equipment which analyzes the received signals and calculates the seat of the aircraft. The main difficulty in the design of this system is reported to have been to create a method for computing complex. Electronics passive radar is designed to extract the desired signal from all available radio noise and the next processing. There is information about the development of a similar system in our country. Receipt of passive radar troops is not expected before 2015. If all this is not yet fully understood the prospects of these systems, although manufacturers, namely concern EADS, is not currently smuschyayutsya voice sounding statements guaranteed detected at least some unobtrusive flying technique.
Candidate new and bold solutions like antenna diversity or passive radar is the way almost representing a certain return to the past. Physics of propagation and reflection of radio waves such that with increasing wavelength increases the visibility of the main indicator of the object — its effective scattering surface. So Makar, returning to the old long-wavelength emitters, you can improve the ability to detect stealth aircraft. Noteworthy that only now confirmed case of liquidation of stealth aircraft specifically related to that procedure. March 27, 1997 was shot down over Yugoslavia South American strike aircraft F-117A, discovered and attacked anti-aircraft missile system S-125. One of the main reasons that led to the destruction of the South American aircraft appeared working range radar detection, working together with a set of S-125. Implementation of spectrum meter waves prevented stealth aircraft technology to express themselves, which led to the next successful attack gunners.
Invisible F-117A stealth was shot down over Yugoslavia, about 20 km from Belgrade, near the airfield Batajnica, the old S-125 radar-guided missiles
Needless to say, the introduction of VHF — far not a panacea. In most modern radars used with the smallest wave length. The fact that an increase in the wavelength range of actions grows, but decreases the accuracy of target coordinates. With decreasing wavelength accuracy grows, but falls detection range. As a result, more comfortable for use in radar was recognized centimeter range, giving a reasonable combination of the detection range and accuracy of determining the location of the target. So Makar, a return to more old radar with a longer wavelength will certainly affect the accuracy of determining the coordinates of the target. In some cases this feature all sorts of long waves may be useless or even harmful to one or another radar or SAM. If you change your radar range also worth considering the fact that promising stealth aircraft, appear to continue to be tailored to suit the likely counter vserasprostranennym more radar stations. Because maybe this development when radar designers will change the emission spectrum, trying to strike a balance between range, accuracy and requirements to counter stealth aircraft designers decisions, and those, in turn, will alter the design and type of aircraft in accordance with current trends in the development of means of detection.
Past experience clearly indicates that at least some protection for the object takes several anti-aircraft complexes and several same means of detection. There is a concept called built-in radar system, which was conceived of its creators, is able to provide reliable protection covers facilities from air attacks. Built-in involves «overlapping» of the 1st and the same neighborhood several radar stations operating at different distances and frequencies. So makarom attempt proparhat inconspicuously for radar built-in turn fail. Part of the reflected signal from one of these stations can get on the other, or a plane would give him a side view, for obvious reasons, poorly adapted to dissipate radio. A similar technique allows to create quite an ordinary methods detect stealth aircraft, but all this has disadvantages. For example, difficult maintenance and attack targets. For effective missile guidance will need to make efficient data transmission system with a «side» on the radar control system SAM. This need is stored in the application of radio-command guided missiles. Introduction of missiles with radar homing — active or passive — also has its corresponding features, partly hinders attack. For example, an effective takeover target seeker is likely only a number of perspectives that does not increase the combat effectiveness of missiles.
Finally, build an air defense system, as well as other systems that use radio waves, vulnerable to attack anti-radar missiles. To prevent the destruction of the station is typically used short-term activation of the transmitter to catch a goal and do not give yourself a missile lock on. But it is likely another way to counter the anti-radar missiles, associated with the absence of any radiation. At the theoretical level detection and tracking of stealth aircraft may be using systems infrared fixing motor. But such a system in 1-x have limited detection range, which also depends on the direction of the target, and in-2 significantly lose their effectiveness at low radiation level, for example, by using special nozzles engines . So Makar, optical location station can hardly be used as the primary means of detection with the required efficiency of existing and promising aircraft performed using stealth technology.
So Makar, at the present time as a countermeasure to stealth technology can be seen at once a few technical or tactical decisions. For all this they all have pluses and minuses. Due to the lack of any means capable guaranteed to look for stealth aircraft, more promising options for future development of detection technologies looks combining different techniques. For example, will have a great ability to structure integral system, in what will be busy as centimetric radar and VHF spectrum. In addition, it looks pretty exciting future development of optical location systems or combined complexes. The latter can combine several principles in detecting, for example, radar and thermal. Finally, recent work in the field of passive location allow to impose a speedy appearance actually applicable complexes working on this principle.
In general, the development of systems to detect air targets is not standing still and is constantly moving forward. Can be fully that in the last time a country will be the new technical solution designed to counter stealth technology. But not worth waiting for revolutionary new ideas, and the development of existing ones. As we see, the existing systems have to evolve. Well, the development of air defense certainly entail improving technologies conceal aircraft.