RU2403584C2 - Adaptive radar set - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: adaptive radar set has a transceiving antenna, a transceiver, a Doppler frequency amplifier, an actuating cascade, first, second and third switches, a detector, a threshold device, a multivibrator, a storage device and a tuning unit, connected in a certain way. The tuning unit is designed for controlling the lower frequency limit of the Doppler frequency amplifier with shift towards higher frequencies.

EFFECT: more reliable detection of head-on low-altitude targets under noise conditions due to radio signals reflected from the surface of the target.

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Description

The proposed adaptive radar relates to the technique of short-range radar and is intended mainly to solve the problem associated with the need to select objects (targets) moving against the background of the surface that creates interference signals.

The requirement for selection of objects arises in many practical cases.

So, for example, target selection against the background of extraneous distributed objects is necessary at the final stages of controlling the movement of short-term interacting objects when meeting aerospace objects with the goal of docking, emergency assistance, controlling the mechanism of the object itself to achieve the ultimate goal - bringing docking devices into operation, etc. .P. (See Kogan I.M. Near Radar (Theoretical Foundations). M., Sov. Radio, 1973. 272 p.).

The selection of an approaching target in the immediate vicinity of the observer is widely used, for example, in systems of radar protection and protection of objects, structures from unauthorized approximations to them.

The problem of unambiguous target selection also arises when protecting marine navigational aids (ships) at the stages of detecting an oncoming anti-ship missile (ASM) with a radio-technical means, for example a radio fuse (which is a short-range radar device) of ammunition designed to destroy a given missile (see B.I. Rodionov NN Novichkov, Cruise missiles in naval combat. M., V. ed. 1987. 215 p.).

Other radars are known for interacting with the target under the influence of various interferences generated by extraneous reflections, in particular, extended sea and terrestrial surfaces (see. Radar Reference. Edited by M. Skolnik. New York, 1970. Transl. From English. Volume 1. The basics of radar. M., Sov. Radio, 1976. 456 p.).

However, none of the existing modern radars can be unambiguously solved the problem of selecting a low-flying target moving over an extended land or sea surface, since when a low-flying target is detected, interference signals generated by reflection from foreign objects, in particular from the underlying surface.

An important requirement for such radars is their noise immunity to all active and passive (intentional or random) interference, often arising from the operation of other both radio engineering and electrical devices located directly on the interacting object.

Thus, the main problem arises of creating a radar for the unambiguous selection of a low-flying target under various interference conditions.

Radars that have an unambiguous target selection and which have a relatively high noise immunity to various external noise include a radar with a continuous complex probing signal [see: 1) Radar devices (theory and construction principles). Ed. V.V. Grigoryan-Ryabov, M., Sov. Radio, 1970.680 s. 2) Varakin L.E. Theory of complex signals. Owls radio, 1970].

Radars are known in which target selection is provided by signal processing in a correlation way, and the distance to the center of the measured range is set by the delay of the signal in the heterodyne path of the correlation receiver [see: 1). Kogan I.M. Near radar. Ed. Owls Radio, M., 1973, S. 29-35. 2) US Patent No. 3614782, MKI GOIS 42C 13/04; NKI 343-7RG, 102-70.2g for 1971].

Of the known closest in technical essence is the radar described in US patent No. 3419861, CL. 343-7, claimed 06/26/56, published. 12/31/68.

This radio device contains a transceiver antenna, a transceiver (which includes: a circulator, a mixer, a delay line), a Doppler frequency amplifier (low-pass filter), an executive circuit.

When the radar meets for the purpose, an echo signal with a Doppler frequency shift is fed to the input of the mixer along with a signal delayed in the delay line weakened in power. A low-pass filter at the mixer output transmits signals in the Doppler frequency range. The output signal of the filter, after reaching a certain level, triggers the actuation circuit.

The main drawback of all such structural diagrams of radars is the low trajectory detection efficiency (probability of correct detection) of a low-flying target over an extended surface, which, for example, can be an anti-ship missile under the influence of interference to the radar, formed by radio signals reflected from different points of ranges located on this surface .

The technical result of the implementation of the proposed adaptive radar is to increase the trajectory reliability of the correct detection of an oncoming low-flying target under conditions of interference with the radar generated by radio signals reflected from this surface.

The technical result is achieved by the fact that to increase the trajectory reliability of a radar detection of a low-flying anti-ship missile by reducing the influence of jamming radio signals generated by reflections of the radio signal from the sea surface into a radar containing a transceiver antenna, a transceiver, a Doppler frequency amplifier, an executive stage, while being reflected from a distributed surface signal through a transceiver antenna, being converted into a Doppler frequency signal in a transceiver ke, enters the input of the Doppler frequency amplifier, the first key, second key, third key, tuning block designed to control the lower cutoff frequency of the Doppler frequency amplifier, with its shift to higher frequencies, detector, threshold device, multivibrator, drive, are introduced, the output of the Doppler frequency amplifier is connected to the first inputs of the first and second keys, the output of the first key is connected to the detector input, the input of the threshold device, the output of which is single with the second input of the second key, with the first input of the third key and the input of the multivibrator, the output of which is connected to the drive and the tuning block in series, the output of which is connected to the second input of the Doppler frequency amplifier, the drive output is connected to the second input of the third key, the output of which is connected to the second input of the first key, and the output of the second key is connected to the executive cascade.

Figure 2 presents the structural diagram of the proposed adaptive radar, which indicates:

transceiver antenna 1,

transceiver 2,

Doppler frequency amplifier 3,

first key 4,

second key 5,

third key 6,

executive stage 7,

tuning block 8,

detector 9,

threshold device 10,

multivibrator 11,

drive 12.

The adaptive radar comprises a transceiver antenna 1, a transceiver 2, a Doppler frequency amplifier 3, a first key 4, a second key 5, a third key 6, an executive stage 7, a tuning unit 8, a detector 9, a threshold device 10, a multivibrator 11, a drive 12, while the output of the Doppler frequency amplifier 3 is connected to the first inputs of the first 4 and second 5 keys, the output of the first key 4 is connected to the input of the detector 9 in series, the input of the threshold device 10, the output of which is connected to the second input of the second key 5, s the first input of the third key 6 and the input of the multivibrator 11, the output of which is connected to the drive 12 and the tuning unit 8, the output of which is connected to the second input of the Doppler frequency amplifier 3, the drive output is connected to the second input of the third key 6, the output of which is connected to the second input the first key 4, and the output of the second key 5 is connected to the executive stage 7.

The proposed adaptive radar (ARL) works as follows.

In the initial position, the first 4, second 5 and third 6 keys are closed (inputs are connected to outputs). When the ARL moves over a distributed surface, the signal reflected from it through the transceiver antenna 4, being converted to the Doppler frequency in the transceiver 5, is fed to the input of the UDF 3. At the output of the UDF 3, a Doppler signal appears due to the movement of the ARV relative to the distributed surface, which is transmitted through the first input of the closed key 5 enters the input of the executive stage 7, and through the first input of the closed first key 4, the detector 9 enters the input, from which the signal enters the input of the threshold device 10, cerned time constant set value less than the time constant of the executive stage 7.

The appearance of the signal at the input of the threshold device 10 causes the appearance of a signal at its output, from where it enters the second input of the second key 5 and the first input of the third key 6, opening the keys 5 and 6 and simultaneously starting the multivibrator 11, from which the pulses are fed to the drive 12, the output of which the voltage grows in proportion to the operating time of the multivibrator 11 and is supplied both to the second input of the third key 6, to the first input of which the output signal of the threshold device 10 is supplied, and to the input of the tuning block 13, which It wishes to set up a lower cutoff frequency UDCH 3 by shifting it toward higher frequencies.

The generating pulses of the multivibrator 11 have a repetition period proportional to the minimum number of pulses for tuning the frequency response of the Doppler frequency amplifier 3 during the time from the beginning of the appearance of the working signal at the output of the UDF 3, caused by the action of reflections from the sea surface and causing the threshold device 10 to operate, until this decreases the signal to a level below the sensitivity of the threshold device 10, after which the signal at the output of the UDM 3 will be only when at its input t signal higher Doppler frequency, for example, reflected from the opposite flying anti-ship missile.

The tuning unit 8 changes the transparency band of the UDM 3, limiting the possibility of amplifying in the UDM 3 signals of those low frequencies that are caused by radio signals reflected from an extended sea surface. After the reconstruction, UDM 3 transmits Doppler signals of higher frequencies, which are formed reflected from an object moving with a higher relative speed of approach, such as, for example, an oncoming anti-ship missile.

Upon reaching the threshold level of the signal at the output of the drive 12, at which the necessary tuning of the frequency response of the UDM 3 is provided, the signal is supplied not only to the input of the tuning block 13, but also to the second input of the third key 6, which, when triggered, supplies the output signal to the second input of the second key 4, which is turned off and its participation in further work is blocked, thereby stopping the possibility of re-tuning the frequency response of UDM 3.

After that, the process of restructuring UDM 3 stops.

After the reconstruction of the UDF 3, the signal that appears again at its output, for example, from an oncoming low-flying observation object through a closed second key 5, enters only the executive stage 7, causing it to operate.

With regard to anti-ship missiles, the use of the proposed adaptive radar can significantly increase the trajectory efficiency of detecting anti-ship missiles that are flying low above the sea surface under the influence of interference generated by radio signals reflected from this surface.

The practical implementation of the proposed adaptive radar is not difficult and can be carried out using well-known analogue elements and integrated circuits (see Integrated circuits. Handbook. Under the general editorship of B.V. Tarabrin. M., Publishing House Sov. Radio, 1984).

The prototype of the proposed adaptive radar made and tested both in laboratory and in-situ conditions showed its full performance under the disturbing interference conditions considered above.

By introducing the proposed new elements and the relationships between them, the problem of creating adaptive short-range radars for the selection of low-flying targets above the earth and sea surface under conditions of interference caused by extraneous reflections is being solved in a fundamentally new way.

Claims (1)

An adaptive radar containing a transceiver antenna, a transceiver, a Doppler frequency amplifier, an executive stage, the signal reflected from a distributed surface through a transceiver antenna, is converted into a Doppler frequency signal in a transceiver, is fed to the input of a Doppler frequency amplifier, characterized in that the first key, second key, third key, tuning block, designed to control the lower cutoff frequency of the Doppler frequency amplifier, with its shift towards higher frequencies, a detector, a threshold device, a multivibrator, a drive, while the output of the Doppler frequency amplifier is connected to the first inputs of the first and second keys, the output of the first key is connected to the detector input, the input of the threshold device, the output of which is connected to the second input the second key, with the first input of the third key and the input of the multivibrator, the output of which is connected to the drive and the tuning block in series, the output of which is connected to the second input by the amplifier of the Doppler frequency, the drive output is connected to the second input of the third key, the output of which is connected to the second input of the first key, and the output of the second key is connected to the executive stage.

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