The long-known radar now appears before us in a completely new light, even if we get acquainted with its latest achievements in general terms. The published review article is devoted to its current state and prospects.

In our time, radar has received the widest application. Its methods and means are used to detect objects and control the situation in the air, space, ground and surface spaces. Modern technology makes it possible to measure with great accuracy the coordinates of the position of an aircraft or rocket, to monitor their movement, to determine not only the shape of objects, but also the structure of their surface. Radar methods open up the possibility of studying the interior of the Earth and even the internal inhomogeneities of the surface layers on other planets. But if we talk about purely "terrestrial affairs" - the civil and military use of radar, then its methods are indispensable, for example, in organizing air traffic control, guidance, recognition of objects, determining their belonging.

Depending on the specific purpose, modern radar stations(radar) have characteristic features. Of all their diversity, a significant proportion are radar detection. This is due to the fact that the radar detection method is the main one both on Earth, in the air, at sea, and in space.

With the help of radar, the so-called spatial selection is performed - the detection of an object by the reflected signal, temporal selection, when the range to the target is set by the delay in the return of the reflected signal. There is also the concept of frequency selection, which makes it possible to track the radial velocity of an observed object by changing the frequency spectrum of a signal.

Modern radars, as a rule, are three-coordinate. They determine the range, elevation and azimuth. In this case, antennas with narrow radiation patterns in the vertical and horizontal planes are used. To ensure the specified accuracy in determining the angular coordinates and not increase the survey time, the method of parallel-sequential survey of space is used, when several beams are used simultaneously, and the zone is covered by the sequential movement of these beams, which makes it possible to reduce the number of receiving channels.

How can interfering reflections from local objects and inhomogeneities in the atmosphere be avoided? Here, in the arsenal of radar, there is a frequency selection mode. Its essence is that an object moving relative to the radar reflects a signal with a frequency shift (Doppler effect). If this shift is even only 10E-7 from the carrier frequency values, then modern methods processing will highlight the difference and the radar will "see" the target. This is ensured by maintaining the necessary stability of the signals, or, as radar specialists say, by maintaining their coherence.

This is important, for example, because objects that cause clutter are often not stationary (trees sway, waves are observed on the water surface, clouds move, etc.). Such reflected signals also have a frequency shift. To expand the capabilities of the radar, various modes of operation of the stations and their combinations are used. With the amplitude mode, it is possible to achieve a greater range of the radar and determine targets moving at zero radial velocity. This method is usually used for viewing in the far field, where there are no interfering reflections. The coherent mode is used in the near field of view, where there are many interfering reflections.

To reduce the peak power of radar transmitters, complex signals are used that provide sufficient accuracy and resolution. At the same time, the equipment has to be complicated. However, in this case, the compromise is quite justified, since it allows to provide the required detection range and not to have a high peak power value.

Many modern radars use phased array antennas (PAR), including those of the active type, each cell of which has its own transmitter and receiver input circuits. This, of course, complicates the design of the station and its maintenance, however, it makes it possible to reduce losses during transmission and reception, and increase the ability of the station to operate in a difficult environment, including artificial interference. At the same time, the inclusion of transceivers in the phased array is one of the important ways to improve the reliability of the radar. Even if several modules of transmitters and receivers fail, the radar continues to operate.
An indispensable quality of modern radars is the preservation for a sufficiently long time and in different weather conditions of the stability of the functioning of the receiving equipment. This problem was solved by the introduction of digital signal processing devices into radar.

An important requirement for modern detection radars is their mobility. They are designed to move on their own on various roads. It takes 5 to 15 minutes to roll up and deploy them. Here, the designers had to drastically limit the mass and dimensions of the radar. In many respects, this problem was solved without worsening the main parameters in terms of range, accuracy, field of view, rate of view, etc.

What does a modern detection radar look like? One of its main elements was a phased antenna array (Fig. 1). It rotates and usually forms several beams for reception and one beam for transmission. The received signals are amplified and then digitized. Further processing of information takes place in digital form with the help of elements of computer technology. The radar actually automatically detects targets, measures coordinates, and determines the parameters of the route.

The operator is almost completely freed from routine work. Its functions are to select the desired mode of operation of the radar, if necessary, i.e. help in its adaptation to the situation and maintain the performance of the radar.

Despite the general patterns of building radar stations for their intended purpose, they are very diverse. For example, modern detection radars are of long, medium, short range; two- and three-coordinate; mobile, mobile, stationary and, finally, for detection at low and high altitudes.

What do the creators of radar systems invest in the concept of "modern radar"? In many respects, it is evaluated by the criterion "efficiency-cost" and can be expressed by a ratio, in the numerator of which is the generalized performance characteristics of the station, and in the denominator - its cost. With such an assessment, simplified radars will have a low indicator due to a small numerator, and overcomplicated radars will have a low indicator due to a large denominator. The optimal ratio for modern radars corresponds to a certain set of scientific and technological achievements used in its creation, which make it possible to increase its capabilities, moreover, achievements that are technologically mastered in production and therefore acceptable in economic terms. And finally, the concept of "modern radar" does not necessarily mean that it has, in all respects, the best performance achieved by world radar technology. Each station design should include such a set of technical innovations that would best allow it to provide the required set of characteristics.

At the same time, it must be emphasized that, despite the functional similarity and diversified nature of modern radar stations, they, as a rule, differ significantly from each other. In radar detection, depending on their purpose, antennas from units to hundreds are used square meters, the average radiated power ranges from hundreds of watts to units of megawatts.

Naturally, the problems of improving radar systems today are being solved on the basis of the latest achievements in mechanics, electromechanics, energy, radio electronics, computer technology, etc. All this suggests that the creation of modern radars is a complex scientific, technical and engineering task.

Among the radar technology that appeared in Lately, are particularly distinguished by their reliability and high functional characteristics military radars. These include radars for detecting means of attack, many of which are characterized by a small reflective surface, made using the so-called "Stealth" ("Invisible") technology. The attack is carried out against the background of artificial active and passive interference to radar detection. At the same time, the radar itself is also subjected to attack: according to the signals that it emits, anti-radar missiles (PRR) are directed at it. It is natural, therefore, that the radar complex, while solving its main combat missions, must also have means of protection against PRR.

Domestic radar has achieved notable success. A number of radar systems created in Russia are our national treasure and are at the world level. Among them, it is quite possible to include radar stations of the meter wave range, including three-coordinate stations.

Obviously, it is worth getting acquainted in more detail with the capabilities of one of our new three-coordinate all-round viewing stations operating in the meter range (Fig. 2). It gives information about the location of the object in the form of three coordinates: in azimuth - 360 °, in range at a distance of up to 1200 km and in height - up to 75 km.

The advantages of such stations, on the one hand, are invulnerability to homing projectiles and anti-radar missiles, which usually use shorter wavelengths, and, on the other hand, the ability to detect Stealth aircraft. After all, one of the reasons for the "invisibility" of these objects is their special shape, which has a small back reflection. In the meter range, this reason disappears, since the dimensions of the aircraft are comparable to the wavelength and its shape no longer plays a decisive role. It is also impossible, without impairing aerodynamics, to cover the aircraft with a sufficient layer of radio-absorbing material. Despite the fact that large antennas are required to operate in this range, and that the stations have some other disadvantages, these advantages of meter-range radars predetermined their development and growing interest in them around the world.

An undoubted achievement of domestic radar can be called radars operating in the decimeter wavelength range for detecting targets flying at low altitudes (Fig. 3). Such a station, against the background of intense reflections from local objects and meteorological formations, is capable of detecting targets at low and extremely low altitudes and escorting helicopters, airplanes, remotely piloted vehicles, and cruise missiles. In automatic mode, it determines the range, azimuth, altitude level and track. All information can be transmitted over a radio channel at a distance of up to 50 km. A characteristic feature of the stations in question is their high mobility (short deployment and collapse time) and the ability to in a simple way lifting antennas to a height of 50 m, i.e. over any vegetation.

These and similar radars have no analogues in the world in many of their characteristics.

Readers of the magazine "Radio" are probably interested in what direction the development of the radar is going in, what will they be like in the near future? It is predicted that, as before, stations of various purposes and levels of complexity will be created. The most complex will be three-coordinate radars. Their common features will remain the principles laid down in modern three-coordinate systems of a circular (or sector) view. Their main functional parts will be active solid-state (semiconductor) phased antenna arrays. Already in the phased array, the signal will be converted into digital form.

A special place in the radar will be occupied by a computer complex. It will take over all the main functions of the station: target detection, determination of their coordinates, as well as station control, including its adaptation to interference conditions, control over the station parameters, and its diagnostics.

And that's not it. The computer complex will generalize the received data, establish a connection with the consumer and give him complete information in finished form.

Today's achievements in science and technology make it possible to predict exactly this kind of radar station in the near future. However, the possibility of creating a universal locator capable of solving all detection tasks is considered doubtful. The emphasis is on complexes of different radars combined into a detection system.

At the same time, an unconventional design of systems will be developed - multi-position radar systems, including passive and active-passive ones, hidden from reconnaissance.

MILITARY UNIVERSITY MILITARY ANTI-AIR

DEFENSE OF THE ARMED FORCES OF THE RUSSIAN FEDERATION

(branch, Orenburg)

Department of Radar Weapons (Reconnaissance Radar and ACS)

Ex. No. _____

The device and operation of the reconnaissance radar Part one The device of the 9s18m1 radar

Approved as a textbook

for cadets and university students,

training centers, formations and units

military air defense

Armed Forces of the Russian Federation

the textbook is intended for cadets and students of universities, training centers, formations and units of the military air defense of the Armed Forces of the Russian Federation, who study the device and operation of reconnaissance radar stations.

The first part of the textbook contains information about the 9S18M1 radar station.

In the second part about the radar station 1L13.

In the third, about the 9S15M, 9S19M2, 35N6 radar stations and the 9S467-1M radar information processing post.

A feature of the textbook is a systematic presentation of educational material from general to particular in accordance with the sequence of passing the discipline "Design and operation of reconnaissance radar" at the Military University of the Air Defense Forces of the RF Armed Forces (branch, Orenburg), as well as using the experience gained at the Department of Radar Weapons and in the troops.

Part 1 of the textbook was developed by the team of authors of the Military University of the Military Air Defense Forces of the Russian Federation (branch, Orenburg), under the guidance of Candidate of Military Sciences, Associate Professor, Major General L. Chukin. M.

The work was attended by: Candidate of Military Sciences, Associate Professor, Colonel Shevchun FN; Candidate of Military Sciences, Associate Professor, Lieutenant Colonel Shchipakin A.Yu.; lieutenant colonel Golchenko I.P.; lieutenant colonel Kalinin D.V.; Associate Professor, Lieutenant Colonel Yu.I. Lyapunov; Candidate of Pedagogical Sciences, Captain Sukhanov P.V.; Candidate of Technical Sciences, Captain Rychkov A.V.; lieutenant colonel Grigoriev G.A.; candidate of pedagogical sciences, lieutenant colonel Dudko A.V.

Approved as a textbook on the discipline "Design and operation of reconnaissance radar" by the head of the military air defense of the RF Armed Forces.

This textbook is the first edition, and the team of authors hopes that possible shortcomings in it will not be a serious hindrance for readers and thanks for the feedback and suggestions aimed at improving the textbook. All feedback and suggestions will be taken into account in the preparation of its next edition.

Our address and phone number: 460010, Orenburg, st. Pushkinskaya 63, FVU RF Armed Forces, Department of Radar Weapons; tel. 8-353-2-77-55-29 (switchboard), 1-23 (department).

Introduction 5

List of abbreviations and symbols 7

I. General information about the 9S18M1 radar. Structural design and placement of the main components 9

1.1 Purpose, composition and design features of the 9S18M1 radar 10

1.2 Tactical and technical characteristics of the radar 12

1.3 Radar operating modes 14

1.4 Structural design and placement of the main components of the radar 17

II. Radar equipment 9S18M1

2.1 a brief description of devices and systems of radar equipment 24

2.2 Operation of the 9S18M1 radar according to block diagram 26

2.3 The operation of the 9S18M1 radar according to the structural and functional scheme 31

2.4 Organization of the overview of space 44

2.5 Power supply system 53

2.6 9S18M1 radar transmitter. Liquid cooling system 79

2.7 Antenna device radar 9S18M1. Waveguide-feeder device 91

2.8 Radar receiver 9S18M1 102

2.9 Radar jamming device 9S18M1 114

2.10 Radar processing and control device 9S18M1 126

2.10.1 Synchronization and interface equipment 139

2.10.2 Equipment for processing radar information radar 9S18M1 150

2.10.3 Radar operator console 9S18M1 153

2.10.4 Specialized digital computing device 160

2.11 General information about the ground radar interrogator 167

2.12 Display device 171

2.13 Communication equipment 187

2.14 External and internal communication equipment 195

2.15 Antenna-rotating device radar 9S18M1 201

2.16 Radar antenna deployment and folding device

2.17 Radar air cooling system 9S18M1 216

2.18 Equipment for navigation, orientation and topographical positioning radar 9S18M1 223

III. General information about the base machine radar 9S18M1 243

IV. General information about the means of maintenance and repair of the radar 9S18M1 261

4.1 Built-in system for monitoring and troubleshooting radar 9S18M1 261

4.2 Purpose, composition and placement of spare parts and accessories. The procedure for finding the necessary element in the ZIP 272

4.3 Purpose, composition and capabilities for maintenance and repair of MRTO 9V894 275

Captain M. Vinogradov,
candidate of technical sciences

Modern radar facilities installed on aircraft and spacecraft currently represent one of the most intensively developing segments of electronic technology. The identity of the physical principles underlying the construction of these tools makes it possible to consider them within the framework of one article. The main differences between space and aviation radars lie in the principles of processing the radar signal associated with different aperture sizes, the characteristics of the propagation of radar signals in different layers of the atmosphere, the need to take into account the curvature of the earth's surface, etc. Despite such differences, the developers of radars with synthesizing aperture (RSA) make every effort to achieve the maximum similarity of the capabilities of these reconnaissance assets.

At present, airborne radars with aperture synthesis allow solving the tasks of specific reconnaissance (shooting the earth's surface in various modes), selection of mobile and stationary targets, analysis of changes in the ground situation, shooting objects hidden in forests, detecting buried and small marine objects.

The main purpose of SAR is a detailed survey of the earth's surface.

Rice. Fig. 1. Shooting modes of modern SAR (a - detailed, b - overview, c - scanning)	Rice. 2. Examples of real radar images with resolutions of 0.3 m (top) and 0.1 m (bottom)
Rice. 3. View of images at different levels of detail
Rice. Fig. 4. Examples of fragments of real areas of the earth's surface obtained at the levels of detail DTED2 (left) and DTED4 (right)

Due to the artificial increase in the aperture of the onboard antenna, the basic principle of which is the coherent accumulation of the reflected radar signals over the synthesis interval, it is possible to obtain a high resolution in angle. In modern systems, resolution can reach tens of centimeters when operating in the centimeter wavelength range. Similar values ​​of range resolution are achieved through the use of intra-pulse modulation, for example, linear frequency modulation (chirp). The interval for synthesizing the antenna aperture is directly proportional to the flight altitude of the SAR carrier, which ensures that the survey resolution is independent of altitude.

At present, there are three main modes of surveying the earth's surface: overview, scanning, and detailed (Fig. 1). In the survey mode, the survey of the earth's surface is carried out continuously in the capture band, while separating the lateral and anterolateral modes (depending on the orientation of the main lobe of the antenna pattern). The accumulation of the signal is carried out for a time equal to the calculated interval for synthesizing the antenna aperture for the given flight conditions of the radar carrier. The scanning shooting mode differs from the survey one in that the shooting is carried out over the entire width of the swath, in strips equal to the width of the capture swath. This mode is used exclusively in space-based radars. When shooting in the detailed mode, the signal accumulation is carried out at an interval increased compared to the overview mode. The increase in the interval is carried out due to the movement of the main lobe of the antenna pattern, synchronous with the movement of the radar carrier, so that the irradiated area is constantly in the shooting area. Modern systems make it possible to obtain images of the earth's surface and objects located on it with resolutions of the order of 1 m for overview and 0.3 m for detailed modes. The Sandia company announced the creation of a SAR for tactical UAVs, which has the ability to shoot with a resolution of 0.1 m in detailed mode. The resulting characteristics of SAR (in terms of surveying the earth's surface) are significantly affected by the methods used for digital processing of the received signal, an important component of which are adaptive algorithms for correcting trajectory distortions. It is the impossibility of maintaining a rectilinear trajectory of the carrier for a long time that makes it impossible to obtain resolutions comparable to the detailed mode in continuous survey mode, although there are no physical restrictions on the resolution in survey mode.

The mode of inverse aperture synthesis (IRSA) allows synthesizing the antenna aperture not due to the movement of the carrier, but due to the movement of the irradiated target. In this case, we can talk not about the translational movement characteristic of terrestrial objects, but about the pendulum movement (in different planes), characteristic of floating craft swinging on the waves. This feature determines the main purpose of IRSA - the detection and identification of marine objects. The characteristics of modern IRSAs make it possible to confidently detect even small objects, such as submarine periscopes. All aircraft in service with the US Armed Forces and other states, whose tasks include patrolling the coastal zone and water areas, are able to shoot in this mode. The images obtained as a result of shooting are similar in their characteristics to the images obtained as a result of shooting with direct (non-inverse) aperture synthesis.

Interferometric survey mode (Interferometric SAR - IFSAR) allows you to get three-dimensional images of the earth's surface. Wherein modern systems have the ability to conduct single-point shooting (that is, use one antenna) to obtain three-dimensional images. To characterize image data, in addition to the usual resolution, an additional parameter is introduced, called height accuracy, or height resolution. Depending on the value of this parameter, several standard gradations of three-dimensional images (DTED - Digital Terrain Elevation Data) are defined:
DTEDO.............................. 900 m
DTED1.............................. 90m
DTED2.............................. 30m
DTED3..............................10m
DTED4...............Sm
DTED5..............................1m

The type of images of an urbanized area (model) corresponding to different levels of detail is shown in fig. 3.

Levels 3-5 are officially known as HRTe-High Resolution Terrain Elevation data. The determination of the location of ground objects on images of level 0-2 is carried out in the WGS 84 coordinate system, the height is measured relative to the zero mark. The coordinate system of high-resolution images is not currently standardized and is under discussion. On fig. Figure 4 shows fragments of real areas of the earth's surface obtained as a result of stereo imaging with different resolutions.

In 2000, the American Shuttle, within the framework of the SRTM (Shuttle Radar Topography Mission) project, the purpose of which was to obtain cartographic information on a large scale, performed an interferometric survey of the equatorial part of the Earth in the band from 60 ° N. sh. to 56°S sh., having received at the output a three-dimensional model of the earth's surface in the DTED2 format. To obtain detailed 3D data in the US, the NGA HRTe? within which images of levels 3-5 will be available.
In addition to radar imaging of open areas of the earth's surface, the airborne radar has the ability to obtain images of scenes hidden from the observer's eyes. In particular, it allows you to detect objects hidden in forests, as well as those located underground.

Penetrating radar (GPR, Ground Penetrating Radar) is a remote sensing system, the principle of which is based on the processing of signals reflected from deformed or differing in composition areas located in a homogeneous (or relatively homogeneous) volume. The earth surface sounding system makes it possible to detect voids, cracks, buried objects located at different depths, to identify areas of different density. In this case, the energy of the reflected signal strongly depends on the absorbing properties of the soil, the size and shape of the target, and the degree of heterogeneity of the boundary regions. At present, GPR, in addition to its military-applied orientation, has developed into a commercially viable technology.

Sounding of the earth's surface occurs by irradiation with pulses with a frequency of 10 MHz - 1.5 GHz. The irradiating antenna may be located on the earth's surface or located on board aircraft. Part of the irradiation energy is reflected from changes in the subsurface structure of the earth, while a large part penetrates further into the depths. The reflected signal is received, processed, and the processing results are shown on the display. When the antenna moves, a continuous image is generated that reflects the state of the subsurface soil layers. Since, in fact, reflection occurs due to the difference in dielectric constants of various substances (or different states of one substance), probing can reveal a large number of natural and artificial defects in a homogeneous mass of subsurface layers. The depth of penetration depends on the condition of the soil at the site of irradiation. The decrease in signal amplitude (absorption or scattering) largely depends on a number of soil properties, the main of which is its electrical conductivity. Thus, sandy soils are optimal for sounding. Clay and very moist soils are much less suitable for this. Good results are shown by probing dry materials such as granite, limestone, concrete.

The sounding resolution can be improved by increasing the frequency of the emitted waves. However, an increase in frequency adversely affects the penetration depth of the radiation. So, signals with a frequency of 500-900 MHz can penetrate to a depth of 1-3 m and provide a resolution of up to 10 cm, and with a frequency of 80-300 MHz they penetrate to a depth of 9-25 m, but the resolution is about 1.5 m.

The main military purpose of subsurface sounding radar is the detection of planted mines. At the same time, the radar installed on board an aircraft, such as a helicopter, allows you to directly open maps of minefields. On fig. Figure 5 shows images from a helicopter-mounted radar showing the location of anti-personnel mines.

Airborne radar, designed to detect and track objects hidden in forests (FO-PEN - FOliage PENetrating), allows you to detect small objects (moving and stationary), hidden by tree crowns. Shooting objects hidden in forests is carried out similarly to conventional shooting in two modes: overview and detail. On average, in the overview mode, the capture bandwidth is 2 km, which makes it possible to obtain images of 2x7 km of the earth's surface at the output; in the detailed mode, the survey is carried out in sections of 3x3 km. The shooting resolution depends on the frequency and varies from 10 m at a frequency of 20-50 MHz to 1 m at a frequency of 200-500 MHz.

Modern image analysis methods make it possible to detect and subsequently identify objects in the received radar image with a sufficiently high probability. In this case, detection is possible on images with both high (less than 1 m) and low (up to 10 m) resolution, while recognition requires images with a sufficiently high (about 0.5 m) resolution. And even in this case, we can talk for the most part only about recognition by indirect signs, since the geometric shape of the object is very strongly distorted due to the presence of a signal reflected from the leaf cover, as well as due to the appearance of signals with a frequency shift due to the Doppler effect that occurs in the result of leaves swaying in the wind.

On fig. 6 shows images (optical and radar) of the same area. Objects (a column of cars) invisible on the optical image are clearly visible on the radar image, however, it is impossible to identify these objects, abstracting from external signs (traffic along the road, the distance between cars, etc.), because with this resolution, information about the geometric structure of the object is completely absent.

The detail of the obtained radar images made it possible to implement in practice a number of features, which, in turn, made it possible to solve a number of important practical problems. One of these tasks is tracking changes that have occurred on a certain area of ​​the earth's surface over a certain period of time - coherent detection. The duration of the period is usually determined by the frequency of patrolling a given area. Tracking of changes is carried out on the basis of the analysis of coordinate-wise combined images of a given area, obtained sequentially one after another. In this case, two levels of analysis detail are possible.

Fig. 5. Maps of minefields in three dimensions when shooting in different polarizations: a model (on the right), an example of an image of a real area of ​​the earth's surface with a complex subsurface situation (on the left), obtained using a radar installed on board a helicopter
Rice. Fig. 6. Optical (above) and radar (below) images of a section of terrain with a convoy of cars moving along a forest road

The first level involves the detection of significant changes and is based on the analysis of the amplitude readings of the image, which carry the main visual information. Most often, this group includes changes that a person can see when simultaneously viewing two generated radar images. The second level is based on the analysis of phase readings and makes it possible to detect changes invisible to the human eye. These include the appearance of traces (of a car or a person) on the road, a change in the state of windows, doors (“open - closed”), etc.

Another interesting SAR capability, also announced by Sandia, is radar video recording. In this mode, the discrete formation of the antenna aperture from section to section, which is characteristic of the continuous survey mode, is replaced by parallel multichannel formation. That is, at each moment of time, not one, but several (the number depends on the tasks being solved) apertures are synthesized. A kind of analogue of the number of formed apertures is the frame rate in conventional video recording. This feature allows you to implement the selection of moving targets based on the analysis of the received radar images, using the principles of coherent detection, which is essentially an alternative to standard radars that select moving targets based on the analysis of Doppler frequencies in the received signal. The effectiveness of the implementation of such selectors of moving targets is very doubtful due to significant hardware and software costs, therefore, such modes will most likely remain nothing more than an elegant way to solve the selection problem, despite the opportunities that open up to select targets moving at very low speeds (less than 3 km/h). h, which is inaccessible to Doppler SDCs). Direct video recording in the radar range has also not found application at the present time, again due to the high requirements for speed, therefore, existing samples military equipment that implement this mode in practice, no.

A logical continuation of improving the technique of surveying the earth's surface in the radar range is the development of subsystems for analyzing the received information. In particular, the development of systems for automatic analysis of radar images, which make it possible to detect, distinguish and recognize ground objects that have fallen into the survey area, is of great importance. The complexity of creating such systems is associated with the coherent nature of radar images, the phenomena of interference and diffraction in which lead to the appearance of artifacts - artificial glare, similar to those that appear when a target with a large effective scattering surface is irradiated. In addition, the quality of the radar image is somewhat lower than the quality of a similar (by resolution) optical image. All this leads to the fact that there are currently no effective implementations of algorithms for recognizing objects in radar images, but the number of works carried out in this area, certain successes achieved recently, suggest that in the near future it will be possible to talk about intelligent unmanned reconnaissance vehicles that have the ability to assess the ground situation based on the results of the analysis of information received by their own airborne radar reconnaissance equipment.

Another direction of development is integration, that is, a coordinated combination with subsequent joint processing of information from several sources. These can be radars shooting in various modes, or radars and other reconnaissance equipment (optical, infrared, multispectral, etc.).

Thus, modern radars with antenna aperture synthesis allow solving a wide range of tasks related to conducting radar surveys of the earth's surface, regardless of the time of day and weather conditions, which makes them an important means of obtaining information about the state of the earth's surface and objects located on it.

Foreign military review No. 2 2009 P. 52-56

The work is headed by the head of the working group of the Scientific and Technical Council of the Military-Industrial Commission for Radio Photonics Alexei Nikolaevich Shulunov. The first steps that can be considered successful have been taken. It seems that a new era is opening in classical radar, which now seems like science fiction.

What is radar know, probably, everyone who graduated at least high school. And what constitutes a radio-photon location is known not to a very large circle of specialists. To put it simply, the new technology allows you to combine the incompatible - the radio wave and light. In this case, the flow of electrons must be converted into a flow of photons and vice versa. The task, which yesterday was beyond reality, can be solved in the near future. What will it give?

For example, the basis of radar systems for missile defense and tracking of space objects are huge radar complexes. The premises in which the equipment is located are multi-storey buildings. The use of photonic technologies will make it possible to fit all control and data processing systems in a much smaller size - literally in a few rooms. At the same time, the technical capabilities of radars to detect even small objects at a distance of thousands of kilometers will only increase. Moreover, due to the use of photonic technologies, not a target mark will appear on the radar screen, but its image, which is unattainable with classical radar. That is, instead of the usual luminous dot, the operator will see what is really flying - an airplane, a rocket, a flock of birds or a meteorite, it is worth repeating, even thousands of kilometers from the radar.

On the screen of the photon radar, not the mark of the target will appear, but its image, which is unattainable with classical radar

Now all radar systems - military and civilian - operate in a strictly defined frequency range, which complicates the technical design and leads to a variety of radar nomenclature. Photon radars will achieve the highest degree of unification. They are able to instantly tune in a very wide range of operating frequencies - from meters to millimeters.

It has long been no secret that the so-called stealth aircraft are also clearly visible in the meter range, but the stations of the centimeter and millimeter ranges give out their coordinates most accurately. Therefore, in air defense systems, both meter stations with very large antennas and more compact centimeter ones work at the same time. But a photon radar, scanning space in a long frequency range, will detect the same "invisibility" without any problems and, instantly retuning to a broadband signal and a high frequency, will determine its exact coordinates in height and range.

It's just about the location. Revolutionary changes will also take place in electronic warfare, in the transmission of information and its protection, in computing technologies and much more. It is easier to say that radio photonics will not affect.

In fact, a fundamentally new branch of high-tech industry will be created. The task is the most difficult, therefore, many leading research centers of the country, university science, a number of industrial enterprises. According to Shulunov, the work is carried out in close connection with the Ministry of Defense, the Ministry of Economic Development, the Ministry of Science and Education. Recently, the President of Russia took control of them.

Modern warfare is swift and fleeting. Often the winner in a combat encounter is the one who is the first to be able to detect a potential threat and respond adequately to it. For more than seventy years, to search for the enemy on land, sea and in the air, a radar method has been used, based on the emission of radio waves and the registration of their reflections from various objects. Devices that send and receive such signals are called radar stations or radars.

The term "radar" is an English abbreviation (radio detection and ranging), which was put into circulation in 1941, but has long since become an independent word and entered most of the world's languages.

The invention of radar is, of course, a landmark event. The modern world is hard to imagine without radar stations. They are used in aviation, in maritime transportation, with the help of radar the weather is predicted, violators of traffic rules are identified, and the earth's surface is scanned. Radar systems (RLK) have found their application in the space industry and in navigation systems.

However, radars are most widely used in military affairs. It should be said that this technology was originally created for military needs and reached the stage of practical implementation just before the start of World War II. All the major countries participating in this conflict actively (and not without result) used radar stations for reconnaissance and detection of enemy ships and aircraft. It can be confidently asserted that the use of radars decided the outcome of several significant battles both in Europe and in the Pacific theater of operations.

Today, radars are used to solve an extremely wide range of military tasks, from tracking the launch of intercontinental ballistic missiles to artillery reconnaissance. Each aircraft, helicopter, warship has its own radar system. Radars are the backbone of the air defense system. The newest radar system with a phased array antenna will be installed on a promising Russian tank "Armata". In general, the variety of modern radars is amazing. These are completely different devices that differ in size, characteristics and purpose.

It can be said with confidence that today Russia is one of the recognized world leaders in the development and production of radars. However, before talking about the trends in the development of radar systems, a few words should be said about the principles of operation of radars, as well as the history of radar systems.

How Radar Works

Location is a method (or process) of determining the location of something. Accordingly, radar is a method of detecting an object or object in space using radio waves that are emitted and received by a device called a radar or radar.

The physical principle of operation of the primary or passive radar is quite simple: it transmits radio waves into space, which are reflected from surrounding objects and return to it in the form of reflected signals. Analyzing them, the radar is able to detect an object at a certain point in space, as well as show its main characteristics: speed, height, size. Any radar is a complex radio engineering device consisting of many components.

The structure of any radar includes three main elements: a signal transmitter, an antenna and a receiver. All radar stations can be divided into two large groups:

• impulse;
• continuous action.

The pulse radar transmitter emits electromagnetic waves for a short period of time (fractions of a second), the next signal is sent only after the first pulse returns back and hits the receiver. The pulse repetition frequency is one of the most important characteristics of a radar. Low frequency radars send out several hundred pulses per minute.

The pulse radar antenna works for both reception and transmission. After the signal is emitted, the transmitter turns off for a while and the receiver turns on. After receiving it, the reverse process occurs.

Pulse radars have both disadvantages and advantages. They can determine the range of several targets at once, such a radar can easily do with one antenna, the indicators of such devices are simple. However, in this case, the signal emitted by such a radar should have a fairly high power. It can also be added that all modern tracking radars are made according to a pulsed scheme.

Pulse radar stations usually use magnetrons, or traveling wave tubes, as the signal source.

The radar antenna focuses the electromagnetic signal and directs it, picks up the reflected pulse and transmits it to the receiver. There are radars in which the reception and transmission of a signal are carried out by different antennas, and they can be located at a considerable distance from each other. The radar antenna is capable of emitting electromagnetic waves in a circle or working in a certain sector. The radar beam can be directed in a spiral or be shaped like a cone. If necessary, the radar can follow a moving target by constantly pointing the antenna at it with the help of special systems.

The functions of the receiver include processing the received information and transferring it to the screen, from which it is read by the operator.

In addition to pulse radars, there are also continuous-wave radars that constantly emit electromagnetic waves. Such radar stations use the Doppler effect in their work. It lies in the fact that the frequency of an electromagnetic wave reflected from an object that approaches the signal source will be higher than from a receding object. The frequency of the emitted pulse remains unchanged. Radars of this type do not fix stationary objects, their receiver picks up only waves with a frequency above or below the emitted one.

A typical Doppler radar is the radar used by traffic police to determine the speed of vehicles.

The main problem of continuous radars is the inability to use them to determine the distance to the object, but during their operation there is no interference from stationary objects between the radar and the target or behind it. In addition, Doppler radars are fairly simple devices that require low-power signals to operate. It should also be noted that modern radar stations with continuous radiation have the ability to determine the distance to the object. To do this, use the change in the frequency of the radar during operation.

One of the main problems in the operation of pulse radars is the interference that comes from stationary objects - as a rule, this is the earth's surface, mountains, hills. During the operation of airborne pulsed aircraft radars, all objects located below are “obscured” by the signal reflected from the earth's surface. If we talk about ground-based or shipborne radar systems, then for them this problem manifests itself in the detection of targets flying at low altitudes. To eliminate such interference, the same Doppler effect is used.

In addition to primary radars, there are so-called secondary radars that are used in aviation to identify aircraft. The composition of such radar systems, in addition to the transmitter, antenna and receiver, also includes an aircraft transponder. When irradiated with an electromagnetic signal, the transponder issues Additional information about altitude, route, board number, its nationality.

Also, radar stations can be divided by the length and frequency of the wave on which they operate. For example, to study the surface of the Earth, as well as to work at considerable distances, waves of 0.9-6 m (frequency 50-330 MHz) and 0.3-1 m (frequency 300-1000 MHz) are used. For air traffic control, a radar with a wavelength of 7.5-15 cm is used, and over-the-horizon radars of missile launch detection stations operate at waves with a wavelength of 10 to 100 meters.

History of radar

The idea of ​​radar arose almost immediately after the discovery of radio waves. In 1905, Christian Hülsmeyer, an employee of the German company Siemens, created a device that could detect large metal objects using radio waves. The inventor suggested installing it on ships so that they could avoid collisions in conditions of poor visibility. However, ship companies were not interested in the new device.

Experiments with radar were also carried out in Russia. As early as the end of the 19th century, the Russian scientist Popov discovered that metal objects prevent the propagation of radio waves.

In the early 1920s, American engineers Albert Taylor and Leo Young managed to detect a passing ship using radio waves. However, the state of the radio engineering industry of that time was such that it was difficult to create industrial models of radar stations.

The first radar stations that could be used to solve practical problems appeared in England around the mid-1930s. These devices were very large and could only be installed on land or on the deck of large ships. It was not until 1937 that a miniature radar prototype was created that could be installed on an aircraft. By the start of World War II, the British had an deployed chain of radar stations called Chain Home.

Engaged in a new promising direction in Germany. And, I must say, not without success. Already in 1935, the Commander-in-Chief of the German Navy, Raeder, was shown a working radar with a cathode-beam display. Later, production models of the radar were created on its basis: Seetakt for the naval forces and Freya for air defense. In 1940, the Würzburg radar fire control system began to enter the German army.

However, despite the obvious achievements of German scientists and engineers in the field of radar, the German army began to use radar later than the British. Hitler and the top of the Reich considered radars to be exclusively defensive weapons, which the victorious German army did not really need. It is for this reason that by the beginning of the Battle of Britain, the Germans had deployed only eight Freya radar stations, although in terms of their characteristics they were at least as good as their British counterparts. In general, it can be said that it was the successful use of radar that largely determined the outcome of the Battle of Britain and the subsequent confrontation between the Luftwaffe and the Allied Air Force in the skies of Europe.

Later, the Germans, based on the Würzburg system, created an air defense line, which was called the Kammhuber Line. Using special forces units, the Allies were able to unravel the secrets of the German radar, which made it possible to effectively jam them.

Despite the fact that the British entered the “radar” race later than the Americans and Germans, at the finish line they managed to overtake them and approach the beginning of World War II with the most advanced radar detection system for aircraft.

Already in September 1935, the British began to build a network of radar stations, which already included twenty radar stations before the war. It completely blocked the approach to the British Isles from the European coast. In the summer of 1940, British engineers created a resonant magnetron, which later became the basis of airborne radar stations installed on American and British aircraft.

Work in the field of military radar was also carried out in the Soviet Union. The first successful experiments on detecting aircraft using radar stations in the USSR were carried out as early as the mid-1930s. In 1939, the first RUS-1 radar was adopted by the Red Army, and in 1940 - RUS-2. Both of these stations were launched into mass production.

Second World War clearly demonstrated the high efficiency of the use of radar stations. Therefore, after its completion, the development of new radars became one of the priority areas for the development of military equipment. Over time, airborne radars were received by all military aircraft and ships without exception, radars became the basis for air defense systems.

During the Cold War, the United States and the USSR acquired a new destructive weapon - intercontinental ballistic missiles. Detecting the launch of these missiles became a matter of life and death. Soviet scientist Nikolai Kabanov proposed the idea of ​​using short radio waves to detect enemy aircraft at long distances (up to 3,000 km). It was quite simple: Kabanov found out that radio waves 10-100 meters long can be reflected from the ionosphere, and irradiating targets on the earth's surface, return the same way to the radar.

Later, based on this idea, radars for over-the-horizon detection of ballistic missile launches were developed. An example of such radars is Daryal, a radar station that for several decades was the basis of the Soviet missile launch warning system.

Currently, one of the most promising areas for the development of radar technology is the creation of a radar with a phased antenna array (PAR). Such radars have not one, but hundreds of radio wave emitters, which are controlled by a powerful computer. Radio waves emitted by different sources in the phased array can amplify each other if they are in phase, or, conversely, weaken.

The phased array radar signal can be given any desired shape, it can be moved in space without changing the position of the antenna itself, and work with different radiation frequencies. A phased array radar is much more reliable and sensitive than a conventional antenna radar. However, such radars also have disadvantages: the cooling of the radar with phased array is a big problem, in addition, they are difficult to manufacture and expensive.

New phased array radars are being installed on fifth-generation fighters. This technology is used in the US missile attack early warning system. Radar complex with PAR will be installed on the newest Russian tank "Armata". It should be noted that Russia is one of the world leaders in the development of PAR radars.

If you have any questions - leave them in the comments below the article. We or our visitors will be happy to answer them.