RU2234714C2 - Pulse type coherent radar - Google Patents

Abstract

FIELD: determination of range and angular coordinates of air targets.

SUBSTANCE: pulse type coherent radar includes phased antenna array, transmitter-receiver, phase switching unit, circulator and indicator. Novelty is that radar also includes electronic control units for controlling beam pattern. Number of said units is equal to that of irradiators; each electronic control unit has irradiator, phase switching circuit, ferrite circulator, first self-excited generator and low-noise amplifier. Radar also includes common device having adder, second self- excited generator, micro controller, receiver and liquid-crystal display. Each irradiator of first inlet-outlet bus is connected with ferrite circulator whose signal inlet is connected with outlet of first self-excited generator. Outlet of ferrite circulator through low-noise amplifier serves as outlet of electronic unit for controlling reception of beam pattern. Outlets of all low-noise amplifiers 1 - N are connected with inlet of adder whose outlet trough receiver is connected with liquid crystal display being outlet of radar. Micro controller is connected through first four-bit control bus with control inlets of phase switches, through third control bus - with control inlets of ferrite circulators and second self-excited generator, through fourth control bus - with control inlets of receiver and liquid-crystal display. Outlet of second self-excited generator through second control bus is connected with first self-excited generators. Irradiators for forming beam pattern in horizontal plane are arranged in two sub-arrays in front edge of wing between ribs in such a way that plane of each irradiator is parallel relative to wing plane. In vertical plane irradiators are arranged in two sub-arrays on nose part of fuselage along two vertical line between stringers in such a way that plane of each irradiator is normal relative to wing plane. Brightness mark from target along X-axis at side from display center shows azimuth angle, along Y-axis - elevation angle, distance to target; approach velocity is displayed by means of digits over brightness mark.

EFFECT: enhanced effectiveness of using radar due to minimization of size-mass its parameters, low level of consumed power, low cost of hardware.

4 cl, 3 dwg

Description

The invention relates to radio engineering, namely to radar, and can be used to determine the range and angular coordinates of air targets. It is preferable to use it in light engine aircraft (LA) as a survey front hemisphere.

All over the world, the vast majority of light-engine aircraft with a capacity of 4-10 people, including the pilot, are not equipped with radars because of the large overall mass characteristics (GMX) of the latter, especially the antenna, also due to the tradition that aircraft pilots do well without them. Currently, Russia is successfully developing in Russia, the CIS, and other countries, therefore, the number of aircraft and air traffic intensity is increasing sharply, and therefore information is required for the pilot about the rapidly changing air situation in order to avoid collisions, especially in conditions of poor visibility.

Given that the flight speeds in LA are small, something within 200-300 km / h, the range of such radars is also small and lies within 15-30 km, which allows you to assess the air situation and have a margin of time to take the necessary actions to build a maneuver of divergence from an oncoming plane or a helicopter, evading high-voltage power lines, towers, etc.

On the other hand, the rapid development of microelectronics drastically reduces GMC, which makes it possible to create on-board radio-electronic equipment, for example, a radar in acceptable weights and dimensions for an aircraft, i.e. to solve the near-radar problem: determining the range, mutual speed and angular coordinates of an air target (with respect to a survey radar).

The TCD 8800 aircraft collision avoidance system is known, which tracks up to 50 targets, simultaneously indicates the three most dangerous ones, and the barometric target height, height difference, distance, etc. are displayed on the indicator. (see the Internet: www.avion.ru.).

The disadvantages of this system are: each aircraft must be equipped with an answering machine, in addition, this system does not reflect the weather, radar terrain.

Known aircraft radar overview of the air environment of the front hemisphere, made according to the classical scheme (according to the state of the art of the late sixties) and having the following technical data in the viewing mode: detection range of up to 10 km, detection zone by maximum range in azimuth ± 60 + 5 °, by elevation (+26) - (14) °, viewing time of the viewing area 1.33 s, range resolution 250 m, azimuth 5 ° (see “Basics of radar and radar equipment of aircraft”, as amended by I .L. Prager, M., Mechanical Engineering, 1 967, p. 232-246).

The disadvantages of this radar are: large GMH, large power consumption, low technical characteristics, but more cannot be required, because that was then the prior art.

Known for a more modern multifunctional radar “Thunderstorm”, installed on almost all types of civil aviation aircraft in Russia and the CIS, which is designed to detect weather patterns, to observe the radar image of the area lying in front of the aircraft, to determine the drift angle and ground speed of the aircraft based on the Doppler effect, and also for viewing the front hemisphere.

Thunderstorm radar station is a pulse radar with an antenna scanning in the azimuthal plane and a sector-based range-azimuth indicator. The radar circuit is based on the structural elements inherent in any pulse station: modulator, transmitter, antenna device with its control unit, antenna switch, reflected signal receiver and indicator.

The modulator generates station start pulses, which are fed to the transmitter. Using a magnetron, powerful microwave pulses are created in the transmitting device, which in shape and duration coincide with the pulses of the modulator. The radio pulses of the transmitter through the waveguide path through the antenna switch enter the antenna, with the help of which both the microwave energy is emitted into space and the electromagnetic waves reflected from the targets are received. The antenna switch at the time of emission of radio pulses automatically connects the antenna to the transmitter, and when receiving reflected signals, respectively, to the receiver.

The radio pulses reflected from the targets and received by the antenna arrive at the receiver, where they are amplified, converted and reproduced in the form of brightness marks on the CRT screen.

The coordination of the work of all elements of the station in time is carried out by synchronization pulses. The beam scan on the screen of the indicator CRT begins simultaneously with the microwave pulses of the transmitter. The sweep line moves across the screen synchronously with the antenna swaying in azimuth. Due to this, a radar image is formed on the screen in the coordinate system “range - azimuth”. In addition, synchronization pulses trigger a device for generating range marks, creating large-scale range arcs on the CRT screen, which determine the slant range to radar targets (see V.V. Glukhov et al. Aviation and Radio-Electronic Equipment of Aircraft. M., Transport, 1983, p. 136-137).

The disadvantages of this radar are large GMHs, and the antenna is made in the form of a rotation paraboloid, which does not fit into the fuselage of aircraft due to its large dimensions, large power consumption, which is critical for aircraft, large dimensions of indicators, etc. this radar does not even fit into the dimensions of the fuselage cockpit.

Known modern aircraft front-view radar "Spear", placed on an external suspension on the attack aircraft SU-25, previously without a radar. This radar has a master oscillator, transmitter, microwave receiver, ADC, signal processor and data processor (see. “Military Parade”, 2000, No. 4, p.30).

The disadvantage of this radar, although made on a modern element base, is the large size, especially the antenna array, which is made in one design, the redundancy in the functions performed, which are used only in military aircraft, i.e. its use in aircraft is practically not profitable and not even possible.

A known radar that uniquely determines the range to targets and the angular coordinates of targets at the industrial frequency of the pulse generator due to the fact that the counter, decoder, four inverters, four coincidence elements, three delay lines and a range converter are introduced, while the synchronizer output is connected to the first the input of the first coincidence element and through the first inverter - with the first input of the second coincidence element, also the output of the synchronizer, through the series-connected counter , the decoder and the second inverter are connected to the second input of the first coincidence element, the output of which is connected to the input of the pulse transmitter, the decoder output is connected through the first delay line to the first input of the range converter, the output of which is connected to the third input of the indicator, the second input of the range converter is connected to the output of the third match element, the first input of which is connected through the second delay line to the output of the second match element, and the second input of the third match element is connected to the output one of the fourth coincidence element, the first input of which is connected to the output of the receiver, which is also connected to the input of the third delay line, the output of which is connected to the second input of the second coincidence element and the input of the third inverter, the output of which is connected to the second input of the fourth coincidence element, in addition the output of the receiver is connected through the fourth inverter to the third input of the second matching element (see RF patent No. 2073883, prototype).

The disadvantages of the prototype are:

- unjustified complexity of the circuit solution, you can solve this problem much easier;

- the antenna system is also not optimal, it has large GMCs, so the placement of this radar on airplanes is not possible.

An object of the invention is to increase the efficiency of application by minimizing the GMC of the radar; low power consumption; low cost of hardware; technological transparency; commercial viability; application of high technology in the microwave path (on microstrip lines (MPL)).

To solve this problem, a pulsed coherent radar is proposed, comprising a phased array, transceiver, phase switch, circulator and indicator, characterized in that it contains electronic radiation pattern control units, the number of which is equal to the number of emitters, and each electronic control unit contains an emitter, phase a switch, a ferrite circulator, a first oscillator and a low-noise amplifier, also the radar contains a common part, which includes the adder, the second oscillator, a microcontroller, a receiver and a liquid crystal indicator, and the radar has the following connections: each emitter of the first input / output bus is connected to a phase switch, which is connected to the ferrite circulator by the second input / output bus, the signal input of which is connected to the output of the first oscillator, and the output ferrite circulator through the low-noise amplifier is the output of the electronic control unit of the radiation pattern for reception, the outputs of all low-noise amplifiers 1-N are connected to the input m of the adder, the output of which through the receiver is connected to the liquid crystal display, which is the output of the radar, the microcontroller of the first four-digit control bus is connected to the control inputs of the phase switches, the third control bus to the control inputs of the ferrite circulators and the second oscillator, the fourth control bus to the control inputs of the receiver and a liquid crystal display, the output of the second oscillator by a second control bus is connected to the first oscillators; HEADLIGHTS radiators forming a directivity pattern (MD) in the horizontal plane are placed in two sublattices in the leading edge of the wing between the ribs, the plane of each radiator being parallel to the wing plane; in the vertical plane, placed in two sublattices of the nose of the fuselage in two vertical lines between the stringers, the plane of each emitter being perpendicular to the wing plane; A liquid crystal display was used as a radar indicator, and the brightness mark from the target along the abscissa axis from the center of the display shows the azimuthal angle, and along the ordinate axis the elevation angle, range to the target, the approach speed is displayed in numbers above the brightness mark.

Figure 1 shows the structural diagram of the radar; figure 2 is an example of the placement of emitters HEADLIGHTS; figure 3 is a view of the LCD with marks of two goals.

Figure 1 shows: 1-N - electronic control units NAM; 2 - emitter; 3 - phase switch (FC); 4 - the first oscillator (AG); 5 - ferrite circulator (FC); 6 - low noise amplifier (LNA); 7 - adder; 8 - second AT; 9 - microcontroller (MK); 10 - receiver; 11 - liquid crystal indicator (LCD); first and second input / output buses; four control and synchronization buses.

The emitter 2 is connected to FC 3 by the first input / output bus, and FC 3 is connected to FC 5 by the second input / output bus, the output of the first oscillator 4 is connected to the signal input of FC 5, the output of which through LNA 6 is connected to the input of adder 7 as are the outputs of all other LNA electronic control units 2-N; the output of the adder 7 is connected to the receiver 10, the output of which is connected to the LCD 11; MK 9 of the first 4-bit control bus is connected to all phase switches of the electronic control units ДН 1-N, the third control bus is connected to FC 5 and the second AG 8, the fourth control bus is connected to receiver 10 of the LCD 11, and the output of the second AG 8 is connected to all autogenerators of electronic control units DN 1-N second control bus.

The indicated nodes and blocks of the radar can be performed on the following electric and radio elements: emitters 2 - on printed emitters, see Antennas and microwave devices, ed. D.I. Voskresensky, M, P and S, 1994, p. 51-52; vibrator on the MPL, ferrite circulars 5 according to the scheme, see Antennas and microwave devices, ed. D. I. Voskresensky, M, P and S, 1994, p. 293-333; phase switch 3 - on p-i-n-diodes using microstrip lines (MPL), see Microelectronic Microwave Devices, ed. G.N. Veselova, M., Higher School, 1988, p. 76-78; LNA 6 - see Microelectronic Microwave Devices, ed. G.N. Veselova, M., Higher School, 1988, p. 173, 201, 225; adder 7 - for example, according to the addition scheme on directional branches, see Microelectronic Microwave Devices, ed. G.N. Veselova. M., Higher School, 1988, p. 73-75; self-oscillators 8 and 4 — on microstrip generators with a Gain diode, see Microwave Microelectronic Devices, ed. G.N. Veselova, M., Higher School, 1988, p. 158-160; receiver 10 is a conventional radar receiver that provides high signal coherence with a synchronous detector, see Theoretical Foundations of Radar, ed. V.E.Dulevich. M., Sov. Radio 1978, p. 79-81; LCD 11 - POWERTYPPG-12864A 128 x 64 dot with backlight, see Aktiv-Matrix-LCD's LDE052T-12 320 × 40 5.1 N 46029, TECHNISCHER KATALOG 96/97, Setron, p. 466 38032, Brauschweig , Germany; MK9 is, for example, a microprocessor manufactured by Jntel 80C 188 EC-16, see the catalog “Sector of electronic components. Russia-99 ”, M., DODEKA, 1999, p. 487.

The radar operates as follows. The microcontroller 9 determines all the time relationships of the radar as a whole and its parts with each other. On the third control bus, a signal is supplied to start the second oscillator 8, which generates a trigger pulse of the common phase. According to this pulse, the first self-oscillator 4 is started, which generates the filling frequency of the starting pulse. At the same time, the ferrite circulator 5 switches to the “transfer” mode and the radio pulse on the second input / output bus goes to the phase switch 3, which assigns the phase of the transmitting signal in accordance with the code received on the first control bus, starting from the zero phase and then through 22.5 ° for all 1-N electronic control units DP first in the horizontal plane, and then in the vertical. After each transmitting pulse, the phase switch and the ferrite circulator switches to “reception” and the reflected pulse from the target (due to the principle of reversibility) is supplied to the LNA 6, then it is summed with reflected pulses from other electronic control units DN 2-N, processed in the receiver 10 and arrives on the LCD 11, where it is displayed in the form of a brightness mark (one or more). It should be noted that in the LCD 11 applied raster scan, i.e. There is no tracking mode for the target (s), but only detection indicating the distance to the target and the mutual speed of approach (removal). These digital data: elevation angle, azimuth angle, range and speed are determined by the microcontroller 9 or the microcontroller, which is located in the LCD 11 (modern LCD for the convenience of displaying information are available with built-in MK).

The antenna system consists of two sublattices: one in the horizontal plane, the other in the vertical, emitters are made in the form of segments of printed conductors, with dimensions at λ = 3 cm.

In this application, the optimal version of the antenna system was found taking into account the existing possibilities for its placement and the operating conditions of the entire system. Optimization consists in approximating the values of the implemented characteristics to the maximum permissible values found for the selected optimality criteria, such as max antenna gain in the scanning sector, etc.

Figure 2 shows the placement of electronic radiation pattern control modules in the wing (horizontal scan) and in the nose of the fuselage (vertical scan); the actual core of the radar (adder, second oscillator, microcontroller, receiver) is made in the form of a separate finished construct and can be located behind the dashboard or nearby, and the LCD directly on the dashboard. A possible arrangement of electronic radiation pattern control modules in the form of two sublattices is only in the nose of the fuselage, because the dimensions of each sublattice have an area of 20 × 40 and a depth of 15 (all dimensions are given in cm) at λ = 3 cm. When using other wavelengths, the sizes can naturally be different.

The approximate data of the proposed radar at a range of 12-15 km are as follows: pulse power less than 100 W, τ imp = 100 μs (time tuning), Rep = 10 kHz, radiation pattern width (LH) of each emitter ≈45 °, total luminance not less than 5 ° vertically and horizontally, the number of emitters in this case in each sublattice is 9, the summation of the power of the emitters is spatial.

The construction of the construct according to the proposed method, i.e. the combination in place of the vibrator and the electronic control unit of the antenna (on the MPL) allows to disperse the headlamp, which leads to a sharp decrease in GMC with more than acceptable technical characteristics.

This construction of the radar can be used on heavier vehicles, such as the Be-103 and even combat, for example on the same Su-25 with an increase in the number of combat functions.

Claims (4)

1. A pulsed coherent radar containing a phased antenna array (PAR), a receiver and an indicator, characterized in that it contains N electronic radiation pattern control units (ND), the number of which is equal to the number of emitters of a phased antenna array, each electronic control unit containing a phase a switch, a ferrite circulator, a first oscillator and a low noise amplifier, in addition, a pulsed coherent radar contains an adder, a second oscillator and a microcontroller, each a phased array antenna emitter is connected by a first input / output bus to a phase switch, which is connected to a ferrite circulator by a second input / output bus, the signal input of which is connected to the output of the first oscillator, and the output of the ferrite circulator through the low-noise amplifier is the output of the DN electronic control unit, the outputs of all low-noise amplifiers are connected to the input of the adder, the output of which through the receiver is connected to the liquid crystal display of the indicator, which is the output of the radar a, the microcontroller with the first four-digit control bus is connected to the control inputs of the phase switches, the third control bus with the control inputs of the ferrite circulators and the second oscillator, the fourth control bus with the control inputs of the receiver and the liquid crystal display of the indicator, the output of the second oscillator with the second control bus is connected to the first oscillators . 2. The pulsed coherent radar according to claim 1, characterized in that the HEADLIGHTER emitters forming a beam in the horizontal plane are placed in two sublattices in the leading edge of the wing between the ribs, the plane of each radiator being parallel to the wing plane. 3. The pulsed coherent radar according to claim 1, characterized in that the PAR emitters in a vertical plane are placed in two sublattices of the nose of the fuselage in two vertical lines between the stringers, the plane of each radiator being perpendicular to the wing plane. 4. The pulsed coherent radar according to claim 1, characterized in that the brightness mark from the target along the abscissa axis from the center of the liquid crystal display of the indicator shows the azimuthal angle, and along the ordinate axis the elevation angle, and the distance to the target, the approach speed is highlighted by numbers above the brightness mark .

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