The latest breakthrough in the field of radar took place several decades ago and was provided by active phased antenna arrays. In recent years, the need for a new such breakthrough has matured, and science already has the necessary groundwork. Further development of radar systems is associated with the development and use of the so-called. radio-photon locators. This concept offers a significant restructuring of the radar, due to which a significant increase in all basic characteristics can be obtained.
According to published data, radio photonic radar can show certain advantages over "traditional" ones. By increasing the efficiency, it is possible to increase the viewing range and target tracking accuracy. There is also the possibility of simplified identification of the detected target. Prospective stations should be distinguished by reduced dimensions, which gives new layout opportunities. However, obtaining practically significant results in a new area is still a matter of the distant future.
Promising projects
The concept of a radio-photon locator has been discussed at the level of theory over the past few years, but until a certain time things did not go further. The situation has changed relatively recently: since the end of 2016, Russian scientific organizations began to regularly talk about new research and the development of promising projects. The latest reports of radio photonic radars appeared just a few weeks ago.
At the very end of 2016, the Russian Foundation for Advanced Study for the first time presented a model of a radio-photon receiving-transmitting module and a broadband emitter for a fundamentally new radar. The prototype used VHF waves and was able to show remarkable characteristics. So, the range resolution has reached 1 m - such indicators are unattainable for "traditional" radars of the same range.
Further work was continued. As it became known later, the Concern "Radioelectronic Technologies" (KRET) is taking part in the promising program. In July 2017, Vladimir Mikheev, Advisor to the First Deputy General Director of KRET, spoke about the development of radio photonic radars. He revealed some technical details of the entire concept and the new project, and also spoke about the current work and plans for the near future.
By that time, an experimental prototype of a new radar station was created at KRET, intended for use on future sixth generation fighter aircraft. As part of the research work, the main components of the locator were built. With their help, the necessary research was carried out, with the help of which it was planned to find the optimal design options. The creation of a full-fledged prototype of a radio-optical photonic antenna array was also carried out. This sample was necessary to test the appearance and characteristics of future serial equipment.
In parallel with the study of the general aspects of the new project, the search for optimal designs of individual elements of the radar was carried out. Such work involved the emitter, the so-called. photonic crystal, receiving path and other components of the station. In the future, all these works will have to lead to the appearance of full-fledged workable samples suitable for installation on media.
In July 2018, it became known that the RTI concern is also involved in the subject of radio photon locators. It was reported that by the end of this year, the organization plans to complete research work on the creation of a mock-up of a new X-band radar station. The product under development is intended for use on tactical combat aircraft. At the same time, as in the case of the KRET project, we are talking not only about the design of the radar, but also about the development of the production of its individual components.
According to the July news, the RTI concern managed to launch the country's first technological line for the production of the so-called. vertically emitting lasers. Such devices are one of the main components of a radio photonic radar and directly affect its characteristics and capabilities. Thus, the Russian industry gets an opportunity in the near future to organize the production of promising stations.
The management of the concern also spoke about plans for the foreseeable future. The RTI enterprise will build on the successes achieved and intend to create new versions of radio photonic radars. First of all, it is planned to create new stations operating in the K, Ka and Q bands. In addition, it is necessary to reduce the dimensions of the products, due to which ultra-wideband airborne radars of new types should appear.
At the end of November, the RTI concern again spoke about its work on a promising project. An experimental prototype of the radar was made, with the help of which the specialists carried out the necessary checks. So far, the existing station is not distinguished by high performance, and besides, it has a lot of operating restrictions. Nevertheless, work under the project continues, and in the future, the promising radar will get rid of the identified problems, which will allow it to reach operation.
Laser instead of semiconductor
The proposed concept of a radio-photonic radar or radio-optical photonic antenna array proposes the abandonment of traditional radar components in favor of new ones that allow obtaining improved characteristics. Modern radar stations generate electromagnetic radiation using vacuum or semiconductor devices. The efficiency of such devices does not exceed 30-40 percent. Accordingly, about two-thirds of the electricity is converted to heat and wasted. The radio photonic station must use other means of signal generation, providing a sharp increase in efficiency.
Last year V. Mikheev, speaking about the new development of KRET, pointed out the main features of the promising stations. The main innovation of the proposed projects is the replacement of semiconductor or lamp devices with a transmitter based on a coherent laser and a special photonic crystal. Laser radiation with the required characteristics is directed to a crystal, which converts it into electromagnetic waves. The efficiency of such a transmitter should exceed 60-70 percent. Thus, the new emitter is about twice as efficient as the traditional one.
Other open sources provide a more complete picture. The radar equipment, which is responsible for issuing, receiving and processing signals, must control the laser, determining its power, modulation and other radiation parameters. The use of optical equipment that transmits a signal through an optical fiber makes it possible to obtain a certain gain in the speed of systems in comparison with other equipment and wiring. In addition, as the experiments show, an emitter based on a laser and a photonic crystal converts more energy into electromagnetic waves than other devices.
In theory, the radio-photonic architecture of the locator can dramatically increase the operating ranges and create a station of an ultra-wideband class. Due to this, a promising radar is capable of taking on the tasks of several traditional systems of different ranges at once. In addition, it provides increased noise immunity and stability with active electronic countermeasures from the enemy.
It was mentioned earlier that an ultra-wideband station is not only immune to interference, but can itself create it. An increased power transmitter with the ability to operate in different ranges is able to take on the role of a jammer. The full realization of this potential of the radar makes it possible to reduce the composition of the on-board electronic warfare equipment or even to abandon other equipment of this purpose altogether. This leads to savings in weight and volume inside the media.
Finally, radio-photonic radar is smaller and lighter than existing counterparts. First of all, this makes it easier to solve layout issues when creating the vehicle carrier of the station. In addition, it becomes possible to equip one combat vehicle with several radar stations at once or one such device with a set of antennas distributed over the surface. Such locators are already used in aviation, and new models are unlikely to remain idle.
The increased performance and the ability to operate in different ranges should lead to new characteristic capabilities. So, last year V. Mikheev said that a radar of a new type will be able not only to determine the location of the target, but also to compose an accurate image of it, suitable for identification. For example, the station will be able to determine the coordinates of an air target, calculate the type of aircraft detected and then recognize which missiles are suspended under its wing.
Radar stations and their carriers
Obviously, the new direction is being worked out with a specific purpose, and the development of the radar is directly related to specific classes of military equipment. In theory, radio photonic stations can be used in all areas where conventional radars are already used. According to reports of recent years, Russian experts have already chosen the scope for the first systems of the new class. They are created for combat aviation, and not only for aircraft.
Earlier it was reported that the radio-photonic radar project from the Concern "Radioelectronic Technologies" is being developed in the context of the next sixth generation fighters. KRET rightly believes that such aircraft should have a set of various detection equipment operating in different ranges and using a wide range of location principles. Together with other systems, the fighter of the future should also have a radio-optical photonic antenna array. In this case, it is possible to use several antenna devices distributed over the entire surface of the airframe and providing a circular view of the space.
Similar principles have already been implemented in the current design of the fifth generation Su-57 fighter, and they should be developed in the creation of the next generation. Probably, by the time the main research and development work on promising radars is completed, the aviation industry will be ready to start developing fundamentally new fighters.
Concern "RTI" is also developing its projects with an eye to military aviation, but is showing interest in a different sector. Prospective locators can have reduced dimensions and weight, which may be of interest to designers of unmanned aerial vehicles. The first samples of ultralight and small-sized radio-photon stations for UAVs are planned to be created within the next few years.
The emergence of new means of observation and detection should have a great impact on the further development of unmanned aircraft. The dimensions and weight of modern aviation radars limit the range of their carriers, in fact, excluding existing and promising domestic UAVs from it. With the advent of lightweight and compact radio photonic radars, the situation will have to change.
Thanks to this, the army will be able to obtain medium or heavy aircraft capable of conducting reconnaissance or piloting not only with the help of optical-electronic means. The positive consequences of the appearance of such UAVs are obvious. Drones with highly effective radars can find applications in a wide variety of areas, from reconnaissance to searching and destroying designated targets.
It has not yet been specified whether promising radars will be introduced into ground technology. The new equipment can be used in stationary and mobile radars, in anti-aircraft systems and in other areas. However, while representatives of the domestic industry did not talk about the possibility of using radio photonic radars outside of aviation.
The question of the future
According to the news of recent years, several leading enterprises of the Russian radio-electronic industry are simultaneously conducting research and development work in a new direction. Several prototypes of various components of promising radar stations have already been completed and tested, and taking into account the data obtained, the following products are being developed. The developers of the new equipment, represented by the KRET and RTI concerns, have decided on their plans and continue to develop projects with clear goals in the context of the development of our military equipment.
However, current projects are complex, which affects the timing of their implementation. Thus, the RTI concern plans to complete the development of a practically applicable radar station within the next few years. KRET, in turn, is creating its own project with an eye on the sixth generation of fighters. Thus, the appearance of ready-made new radio-photon locators, suitable for use on equipment, is a matter of medium or long-term prospects.
However, the expected timing of the emergence of promising equipment is not a problem. Our industry and army already have highly efficient modern radar stations capable of solving all assigned tasks. With their help, the army will be able to have all the required capabilities up to the emergence of fundamentally new systems. In addition, the emergence of radio photonic stations can hardly be expected to halt the development of "traditional" systems. Thus, in the future, the troops will be able to timely receive all the necessary detection systems, both already mastered and fundamentally new.
