BALTIC STATE TECHNICAL UNIVERSITY

_____________________________________________________________

Department of Radioelectronic Devices

RADAR HOMING HEAD

Saint Petersburg

2. GENERAL INFORMATION ABOUT RLGS.

2.1 Purpose

The radar homing head is installed on the surface-to-air missile to ensure automatic target acquisition, its auto-tracking and the issuance of control signals to the autopilot (AP) and radio fuse (RB) at the final stage of the missile's flight.

2.2 Specifications

RLGS is characterized by the following basic performance data:

1. search area by direction:

Elevation ± 9°

2. search area review time 1.8 - 2.0 sec.

3. target acquisition time by angle 1.5 sec (no more)

4. Maximum angles of deviation of the search area:

In azimuth ± 50° (not less than)

Elevation ± 25° (not less than)

5. Maximum deviation angles of the equisignal zone:

In azimuth ± 60° (not less than)

Elevation ± 35° (not less than)

6. target capture range of the IL-28 aircraft type with the issuance of control signals to (AP) with a probability of not less than 0.5 -19 km, and with a probability of not less than 0.95 -16 km.

7 search zone in range 10 - 25 km

8. operating frequency range f ± 2.5%

9. average transmitter power 68W

10. RF pulse duration 0.9 ± 0.1 µs

11. RF pulse repetition period T ± 5%

12. sensitivity of receiving channels - 98 dB (not less)

13.power consumption from power sources:

From the mains 115 V 400 Hz 3200 W

Mains 36V 400Hz 500W

From the network 27 600 W

14. station weight - 245 kg.

3. PRINCIPLES OF OPERATION AND CONSTRUCTION OF RLGS

3.1 The principle of operation of the radar

RLGS is a radar station of the 3-centimeter range, operating in the mode of pulsed radiation. At the most general consideration, the radar station can be divided into two parts: - the actual radar part and the automatic part, which provides target acquisition, its automatic tracking in angle and range, and the issuance of control signals to the autopilot and radio fuse.

The radar part of the station works in the usual way. High-frequency electromagnetic oscillations generated by the magnetron in the form of very short pulses are emitted using a highly directional antenna, received by the same antenna, converted and amplified in the receiving device, pass further to the automatic part of the station - the target angle tracking system and the rangefinder.

The automatic part of the station consists of the following three functional systems:

1. antenna control systems that provide antenna control in all modes of operation of the radar station (in the "pointing" mode, in the "search" mode and in the "homing" mode, which in turn is divided into "capture" and "autotracking" modes)

2. distance measuring device

3. a calculator for control signals supplied to the autopilot and radio fuse of the rocket.

The antenna control system in the "autotracking" mode works according to the so-called differential method, in connection with which a special antenna is used in the station, consisting of a spheroidal mirror and 4 emitters placed at some distance in front of the mirror.

When the radar station operates on radiation, a single-lobe radiation pattern is formed with a maμmum coinciding with the axis of the antenna system. This is achieved through different lengths emitter waveguides - there is a hard phase shift between the oscillations of different emitters.

When working at reception, the radiation patterns of the emitters are shifted relative to the optical axis of the mirror and intersect at a level of 0.4.

The connection of the emitters with the transceiver is carried out through a waveguide path, in which there are two ferrite switches connected in series:

· Axes commutator (FKO), operating at a frequency of 125 Hz.

· Receiver switch (FKP), operating at a frequency of 62.5 Hz.

Ferrite switches of the axes switch the waveguide path in such a way that first all 4 emitters are connected to the transmitter, forming a single-lobe directivity pattern, and then to a two-channel receiver, then emitters that create two directivity patterns located in a vertical plane, then emitters that create two patterns orientation in the horizontal plane. From the outputs of the receivers, the signals enter the subtraction circuit, where, depending on the position of the target relative to the equisignal direction formed by the intersection of the radiation patterns of a given pair of emitters, a difference signal is generated, the amplitude and polarity of which is determined by the position of the target in space (Fig. 1.3).

Synchronously with the ferrite axis switch in the radar station, the antenna control signal extraction circuit operates, with the help of which the antenna control signal is generated in azimuth and elevation.

The receiver commutator switches the inputs of the receiving channels at a frequency of 62.5 Hz. The switching of receiving channels is associated with the need to average their characteristics, since the differential method of target direction finding requires the complete identity of the parameters of both receiving channels. The RLGS rangefinder is a system with two electronic integrators. From the output of the first integrator, a voltage proportional to the speed of approach to the target is removed, from the output of the second integrator - a voltage proportional to the distance to the target. The range finder captures the nearest target in the range of 10-25 km with its subsequent auto-tracking up to a range of 300 meters. At a distance of 500 meters, a signal is emitted from the rangefinder, which serves to cock the radio fuse (RV).

The RLGS calculator is a computing device and serves to generate control signals issued by the RLGS to the autopilot (AP) and RV. A signal is sent to the AP, representing the projection of the vector of the absolute angular velocity of the target sighting beam on the transverse axes of the missile. These signals are used to control the missile's heading and pitch. A signal representing the projection of the velocity vector of the target's approach to the missile onto the polar direction of the target's sighting beam arrives at the RV from the calculator.

The distinctive features of the radar station in comparison with other stations similar to it in terms of their tactical and technical data are:

1. the use of a long-focus antenna in a radar station, characterized by the fact that the beam is formed and deflected in it using the deflection of one rather light mirror, the deflection angle of which is half that of the beam deflection angle. In addition, there are no rotating high-frequency transitions in such an antenna, which simplifies its design.

2. use of a receiver with a linear-logarithmic amplitude characteristic, which provides an expansion of the dynamic range of the channel up to 80 dB and, thereby, makes it possible to find the source of active interference.

3. building a system of angular tracking by the differential method, which provides high noise immunity.

4. application in the station of the original two-circuit closed yaw compensation circuit, which provides a high degree of compensation for the rocket oscillations relative to the antenna beam.

5. constructive implementation of the station according to the so-called container principle, which is characterized by a number of advantages in terms of reducing the total weight, using the allotted volume, reducing interconnections, the possibility of using a centralized cooling system, etc.

3.2 Separate functional radar systems

RLGS can be divided into a number of separate functional systems, each of which solves a well-defined particular problem (or several more or less closely related particular problems) and each of which is to some extent designed as a separate technological and structural unit. There are four such functional systems in the RLGS:

3.2.1 Radar part of the RLGS

The radar part of the RLGS consists of:

the transmitter.

receiver.

high voltage rectifier.

the high frequency part of the antenna.

The radar part of the RLGS is intended:

· to generate high-frequency electromagnetic energy of a given frequency (f ± 2.5%) and a power of 60 W, which is radiated into space in the form of short pulses (0.9 ± 0.1 μs).

for subsequent reception of signals reflected from the target, their conversion into intermediate frequency signals (Ffc = 30 MHz), amplification (via 2 identical channels), detection and output to other radar systems.

3.2.2. Synchronizer

Synchronizer consists of:

Receiving and Synchronization Manipulation Unit (MPS-2).

· receiver switching unit (KP-2).

· Control unit for ferrite switches (UF-2).

selection and integration node (SI).

Error signal selection unit (CO)

· ultrasonic delay line (ULZ).

generation of synchronization pulses for launching individual circuits in the radar station and control pulses for the receiver, SI unit and rangefinder (MPS-2 unit)

Formation of impulses for controlling the ferrite switch of axes, the ferrite switch of the receiving channels and the reference voltage (UV-2 node)

Integration and summation of received signals, voltage regulation for AGC control, conversion of target video pulses and AGC into radio frequency signals (10 MHz) to delay them in the ULZ (SI node)

· isolation of the error signal necessary for the operation of the angular tracking system (CO node).

3.2.3. Rangefinder

The rangefinder consists of:

Time modulator node (EM).

time discriminator node (VD)

two integrators.

The purpose of this part of the RLGS is:

search, capture and tracking of the target in range with the issuance of signals of the range to the target and the speed of approach to the target

issuance of signal D-500 m

Automatic devices installed on combat charge carriers (NBZ) - missiles, torpedoes, bombs, etc. to ensure a direct hit on the object of attack or approach at a distance less than the radius of destruction of charges. homing heads perceive the energy emitted or reflected by the target, determine the position and nature of the movement of the target and generate the appropriate signals to control the movement of the NBZ. According to the principle of operation, the homing heads are divided into passive (perceive the energy emitted by the target), semi-active (perceive the energy reflected from the target, the source of which is outside the homing head) and active (perceive the energy reflected from the target, the source of which is in the head itself). homing); by type of perceived energy - into radar, optical (infrared or thermal, laser, television), acoustic, etc .; by the nature of the perceived energy signal - into pulsed, continuous, quasi-continuous, etc.
The main nodes of the homing heads are coordinator and electronic computing device. The coordinator provides for the search, capture and tracking of the target in terms of angular coordinates, range, speed and spectral characteristics of the perceived energy. The electronic computing device processes the information received from the coordinator and generates control signals for the coordinator and the movement of the NBZ, depending on the adopted method of guidance. This ensures automatic tracking of the target and guidance of the NBZ on it. In the coordinators of passive homing heads, receivers of energy emitted by the target (photoresistors, television tubes, horn antennas, etc.) are installed; target selection, as a rule, is carried out according to the angular coordinates and the spectrum of the energy emitted by it. In the coordinators of semi-active homing heads, a receiver of energy reflected from the target is installed; target selection can be carried out according to angular coordinates, range, speed and characteristics of the received signal, which increases the information content and noise immunity of the homing heads. In the coordinators of active homing heads, an energy transmitter and its receiver are installed, target selection can be carried out similarly to the previous case; active homing heads are fully autonomous automatic devices. Passive homing heads are considered the simplest in design, active homing heads are considered the most complex. To increase the information content and noise immunity can be combined homing heads, in which various combinations of operating principles, types of perceived energy, methods of modulation and signal processing are used. An indicator of the noise immunity of homing heads is the probability of capturing and tracking a target in conditions of interference.
Lit .: Lazarev L.P. Infrared and light devices for homing and guidance of aircraft. Ed. 2nd. M., 1970; Design of rocket and receiver systems. M., 1974.
VC. Baklitsky.

The creation of systems for high-precision targeting of long-range ground-to-ground missiles is one of the most important and complex problems in the development of high-precision weapons (HW). This is primarily due to the fact that, other things being equal, land targets have a significantly lower “useful signal/interference” ratio compared to sea and air targets, and the launch and guidance of the missile are carried out without direct contact between the operator and the target.

In high-precision ground-to-ground long-range missile systems that implement the concept of effective engagement of ground targets with combat units of conventional equipment, regardless of the firing range, inertial navigation systems are integrated with missile homing systems that use the principle of navigation along geophysical fields of the Earth. The inertial navigation system as the basic one provides high noise immunity and autonomy of integrated systems. This provides a number of undeniable advantages, including in the context of continuous improvement of missile defense systems.

For complexing inertial systems control systems with homing in the geophysical fields of the Earth, first of all, a special information support system is needed.

The ideology and principles of the information support system are determined by the main characteristics of the objects of destruction and the weapons systems themselves. Functionally information support of high-precision missile systems includes such main components as receiving and decrypting intelligence information, developing target designation, bringing target designation information to complexes missile weapons.

The most important element of high-precision missile guidance systems are homing heads (GOS). One of the domestic organizations involved in developments in this area is the Central Research Institute of Automation and Hydraulics (TsNIIAG), located in Moscow. A lot of experience was accumulated there in the development of guidance systems for surface-to-surface missiles with homing heads of optical and radar types with correlation-extreme signal processing.

The use of correlation-extreme homing systems on maps of geophysical fields by comparing the values ​​of the geophysical field measured in flight with its reference map stored in the memory of the onboard computer makes it possible to eliminate a number of accumulated control errors. For homing systems based on an optical image of the terrain, an optical reconnaissance image can serve as a reference map, in which the target is determined with virtually no errors in relation to the elements of the surrounding landscape. Because of this, the GOS, guided by the elements of the landscape, is directed precisely at the specified point, regardless of the accuracy with which its geographical coordinates are known.

The emergence of prototypes of optical and radar correlation-extreme systems and their GOS was preceded by a huge amount of theoretical and experimental research in the field of computer science, theories of pattern recognition and image processing, the basics of developing hardware and software for current and reference images, organizing banks of background-target environments of various plots earth's surface in various ranges of the electromagnetic spectrum, mathematical modeling GOS, helicopter, aircraft and missile tests.

The design of one of the variants of the optical seeker is shown in rice. 1 .

The optical seeker provides in-flight recognition of a landscape area in the target area by its optical image formed by the coordinator lens on the surface of a matrix multi-element photodetector. Each element of the receiver converts the brightness of the corresponding area of ​​the terrain into an electrical signal that is fed to the input of the encoder. The binary code generated by this device is stored in the computer memory. It also stores the reference image of the desired area, obtained from a photograph and encoded using the same algorithm. When approaching the target, stepwise scaling is carried out by recalling reference images of the appropriate scale from the computer memory.

Recognition of a piece of terrain is carried out in the modes of capturing and tracking the target. In the target tracking mode, a non-search method is used, based on the algorithms of pattern recognition theory.

The operation algorithm of the optical seeker makes it possible to generate control signals both in the direct guidance mode and in the guidance angle extrapolation mode. This allows not only to increase the accuracy of pointing the missile at the target, but also to provide extrapolation of control signals in the event of a failure in target tracking. The advantage of optical seeker is a passive mode of operation, high resolution, small weight and dimensions.

Radar seekers provide high weather, seasonal and landscape reliability with a significant reduction in instrumental errors in the control and target designation systems. General form one of the variants of the radar seeker is shown on rice. 2 .

The principle of operation of the radar seeker is based on a correlation comparison of the current radar brightness image of the terrain in the target area, obtained on board the missile using a radar, with reference images previously synthesized from primary information materials. As primary information materials topographic maps, digital terrain maps, aerial photographs, space images and a catalog of specific effective scattering surfaces are used, which characterize the reflective radar properties of various surfaces and ensure the conversion of optical images into radar images of the terrain that are adequate to current images. The current and reference images are presented in the form of digital matrices, and their correlation processing is carried out in the on-board computer in accordance with the developed comparison algorithm. The main purpose of the operation of the radar seeker is to determine the coordinates of the projection of the center of mass of the rocket relative to the target point in conditions of work on terrain of various information content, given meteorological conditions, taking into account seasonal changes, the presence of electronic countermeasures and the influence of rocket flight dynamics on the accuracy of removing the current image.

The development and further improvement of optical and radar seekers are based on scientific and technical achievements in the field of informatics, computer technology, image processing systems, on new technologies for creating seekers and their elements. High-precision homing systems currently being developed have absorbed the accumulated experience and modern principles for creating such systems. They use high-performance on-board processors that allow real-time implementation of complex algorithms for the functioning of systems.

The next step in creating accurate and reliable homing systems for high-precision ground-to-ground missiles was the development of multispectral correction systems for the visible, radio, infrared and ultraviolet ranges, integrated with channels for direct guidance of missiles to a target. The development of channels for direct guidance to a target is associated with significant difficulties associated with the characteristics of targets, missile trajectories, the conditions for their use, as well as the type of warheads and their combat characteristics.

The complexity of target recognition in the direct guidance mode, which determines the complexity of the software and algorithmic support for high-precision guidance, has led to the need for intellectualization of guidance systems. One of its directions should be considered the implementation of artificial intelligence principles in systems based on neural networks.

Significant progress in fundamental and applied sciences in our country, including in the field of information theory and systems theory with artificial intelligence, make it possible to implement the concept of creating super-precise, precision missile systems for hitting ground targets that ensure efficiency in a wide range of combat conditions. One of the latest developments in this area is the Iskander operational-tactical missile system.

homing head

The homing head is an automatic device that is installed on a guided weapon in order to ensure high targeting accuracy.

The main parts of the homing head are: a coordinator with a receiver (and sometimes with an energy emitter) and an electronic computing device. The coordinator searches, captures and tracks the target. The electronic computing device processes the information received from the coordinator and transmits signals that control the coordinator and the movement of the controlled weapon.

According to the principle of operation, the following homing heads are distinguished:

1) passive - receiving the energy radiated by the target;

2) semi-active - reacting to the energy reflected by the target, which is emitted by some external source;

3) active - receiving energy reflected from the target, which is emitted by the homing head itself.

According to the type of energy received, the homing heads are divided into radar, optical, acoustic.

The acoustic homing head functions using audible sound and ultrasound. Its most effective use is in water, where sound waves decay more slowly than electromagnetic waves. Heads of this type are installed on controlled means of destroying sea targets (for example, acoustic torpedoes).

The optical homing head works using electromagnetic waves in the optical range. They are mounted on controlled means of destruction of ground, air and sea targets. Guidance is carried out by a source of infrared radiation or by the reflected energy of a laser beam. On guided means of destruction of ground targets, related to non-contrast, passive optical homing heads are used, which operate on the basis of an optical image of the terrain.

Radar homing heads work using electromagnetic waves in the radio range. Active, semi-active and passive radar heads are used on controlled means of destruction of ground, air and sea targets-objects. On controlled means of destruction of non-contrasting ground targets, active homing heads are used, which operate on radio signals reflected from the terrain, or passive ones that operate on the radiothermal radiation of the terrain.

This text is an introductory piece. From the book Locksmith's Guide by Phillips Bill

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