RU200828U1 - A DEVICE FOR RADAR RECOGNITION OF CLASSES OF AIR-SPACE OBJECTS IN A MULTI-BAND RADAR COMPLEX WITH PHASED ANTENNA ARRAYS - Google Patents

Abstract

The utility model relates to radar and can be used for radar class recognition (RRK) of aerospace objects (VKO) in multi-band radar complexes with phased antenna arrays and two-dimensional electronic scanning and pulse-by-pulse frequency tuning. The technical result of the utility model is an improvement in tactical and technical characteristics. , which consists in expanding the alphabet of recognized classes of aerospace defense and increasing the probability of correct recognition of aerospace defense, as well as the possibility of detecting false targets imitating signals from a probing radar module (RLM), is achieved through the use of an additional recognition feature (correlation feature) obtained by calculating the dependences of the effective surface values scattering (EPR) from pulse-by-pulse tunable sounding frequencies, which can be obtained both in a long-wavelength RLM, which performs a rough estimate of the parameters of the aerospace defense in a circular view and at large distances and in a short-wave radar, capable of keeping the beam in the direction of the target for a long time to accumulate a signal, and performing accurate measurements of the aerospace defense parameters at a quasi-optimal spacing of the probing frequencies, as well as by calculating the dependence of the change in the RCS values of an airborne object on the distance to this object, as a result of which false air objects are detected, imitating aerospace defense of other classes. Moreover, this procedure can be performed by RLM of different wavelength ranges, which makes it possible to perform selection at a higher quality level. 1 dwg, 1 tbl

Description

The utility model relates to radar and can be used for radar class recognition (RRK) of aerospace objects (VKO) in multi-band radar complexes with phased antenna arrays and two-dimensional electronic scanning and pulse-by-pulse frequency tuning.

In this utility model, it is proposed to use the technologies of adaptive interaction of radar modules (RLM) of different wavelength ranges, which allow, with two-stage recognition in dual-band complexes and the use of additional recognition signs, to increase the probability of correct RRK VKO and significantly reduce the time spent on solving this problem, as well as to produce selection of false targets.

The closest in technical essence is a device for recognizing aerospace defense in dual-band radar systems with active phased array (RF patent No. 2665032 C2, IPC G01S 13/52, published on August 27, 2018), using two radar stations for two-stage recognition of aerospace defense at different wavelength ranges and taken as a prototype [1].

This device contains a radar information processing unit, a vertical velocity component, a track speed computer, a first level classifier, a second level classifier, a frequency recognition feature calculator and a frequency feature averaging unit, an effective scattering area calculator and an effective scattering area averaging unit, a device for selecting air objects , a device for selecting operating frequencies, a longitudinal dimension calculator, and a parametric classifier.

The disadvantage of the prototype is the insufficient probability of correct recognition and large time resources allotted for this procedure, as well as the lack of selection of false targets that use synchronous counter-interference to mask real targets.

The technical result of the claimed utility model is to improve the tactical and technical characteristics, which consists in expanding the alphabet of recognized classes of aerospace defense and increasing the probability of correct recognition of aerospace defense, as well as the possibility of detecting false targets imitating signals from the probing radar.

The goal is achieved through the use of an additional recognition feature (correlation feature) obtained by calculating the dependences of the effective scattering surface (ESR) values on pulse-by-pulse tunable probing frequencies σ _c (ƒ), which can be obtained both in the long-wavelength RLM, which provides a rough estimate of the parameters of the VKO with circular survey both at long ranges and in a short-wave radar, capable of keeping the beam in the direction of the target for a long time to accumulate a signal, and performing accurate measurements of the aerospace defense parameters at a quasi-optimal spacing of the probing frequencies, as well as by calculating the dependence of the change in the RCS values of an air object from the distance to this object, as a result of which false air objects are detected, imitating aerospace defense of other classes. Moreover, this procedure can be performed by RLM of different wavelength ranges, which makes it possible to perform selection at a higher quality level.

The claimed result is achieved due to the fact that a device containing a radar information processing unit (BO), a vertical velocity component (VVSS), a track velocity computer (VTS), a frequency recognition feature (VCHPR) computer, an effective scattering area calculator (VEPR) , classifier of the first level (KPU), classifier of the second level (KVU), block of averaging of the frequency attribute (AUCHPR), unit of averaging of the effective area of scattering (AUEPR), device for selecting air objects (UVVO), device for selecting operating frequencies (UHRCH), calculator of longitudinal size (VPR), as well as a parametric classifier (PC), additionally introduced a false target recognition unit (BRLTs) and a unit of the correlation feature of recognition (BKPR).

The figure shows a block diagram of the proposed device with the following designations:

1 - radar data processing unit (BO);

2 - calculator of the vertical component of speed (VVSS);

3 - track speed computer (VTS);

4 - calculator of the frequency recognition feature (VCHPR);

5 - EPR calculator (VEPR);

6 - first level classifier (KPU);

7 - classifier of the second level (KVU);

8 - block of averaging of the frequency recognition feature (BUCHPR);

9 - false target recognition unit (BRLTs);

10 - device for selecting air objects (UVVO);

11 - device for selecting operating frequencies (UHRCH);

12 - EPR averaging unit (BUEPR);

13 - calculator of the longitudinal dimension (VPR);

14 - block of the correlation feature of recognition (BKPR);

15 - parametric classifier (PC).

The proposed device consists of a block for processing radar information BO 1, a calculator of the vertical component of the speed VVSS 2, a calculator of the route velocity VTS 3, a calculator of the frequency indication of the recognition of VCHPR 4 with its averaging unit BUCHPR 8, an EPR calculator VEPR 5, with its averaging block BUEPR 12, a block false target recognition BRLTs 9, classifiers of the first and second levels KPU 6 and KVU 7, respectively, a device for selecting air objects UVVO 10, a device for selecting operating frequencies of the UVRCH 11, a calculator of the longitudinal size VPR 13, a block of the correlation sign of recognition of the BKPR 14 and a parametric classifier PC 15 The first, second and third outputs of BO 1 are connected, respectively, with the first input, through the VVSS 2 with the second input and through the VTS 3 with the third input of the KPU 6, the second output of the VVSS 2 is connected to the first input of the VTS 3, and the output of the KPU 6 - with input KVU 7, the first and second outputs of KVU 7 are connected, respectively, with the first input of PC 15 and with the first input of UVVO 10, the second The th input of the UVVO 10 is connected to the fourth output of the BO 1, and the third input is connected to the output of the UVRCH 11, the first input of which is connected to the second output of the UVVO 10, the first output of which is the first output of the device, and the second input through the VCHPR 4 is connected in series with the fifth output BO 1 and the first output of BUCHPR 8, the second output of which is connected to the first input of BKPR 14, the sixth output of BO 1 through VPR 13 is connected to the second input of PC 15, and the seventh output of BO 1 through series-connected VEPR 5 is connected to BRLTs 9, the first output of which connected through a series-connected BUEPR 12 with the second input of the BKPR 14, and the second output is connected to the fourth input of the PC 15, the BKPR 14 is connected to the third input of the PC 15, the output of which is the second output of the device.

In this case, the BO is made with the additional possibility of generalized (from two modules) secondary processing of radar information and calculation of the route priority based on data on the results of state identification of an airborne object, its range and flight speed.

The input of BO 1 receives information about the EKO echo signals detected by the RLM modules of the meter and decimeter (centimeter) wavelength range, containing the range, azimuth, elevation angle and amplitude of echo signals at each sounding frequency, as well as information about the state ownership of the EKO. BO 1 recalculates coordinates into a rectangular system, ties the track along the EKO, links the detected echo signals to existing tracks, measures the speed of the EKO along the coordinates x and y (V _x , V _y ) generalized from two modules and its height, and also calculates the priority of the route ... The amplitudes of echo signals received from the receivers of the radar modules at each sounding frequency of the BO 1 are relayed to the calculator of the frequency recognition attribute of the VCHPR 4, to the EPR calculator of the airborne object VEPR 5 and to the calculator of the longitudinal size VPR 13.

The data on the altitude of the EKO, calculated using the elevation angle measured by the decimeter (centimeter) module, is sent from the first output of BO 1 to the first input of the classifier of the first level of KPU 6, and from the second output of BO 1 to the input of the VVSS 2 calculator, in which the value of the vertical component is determined speed according to the formula:

The value of the vertical component of the speed is fed to the second input of the KPU 6 and to the first input of the VTS 3, to the input of which the values of the horizontal components of the velocities V _x , V _y are received from the third output of the BO 1.

In MTC 3, the value of the route speed of the aerospace defense is calculated by the formula:

Further, V _Ti is fed to the third input of the KPU 6, in which the information about the height of the VKO, its vertical component of the speed and the route speed is compared with a priori given information about the possible values of these features for each target class. A priori information is put into KPU 6 in the form of coordinates of points of the planes "track speed - height", and "vertical component of speed - height", which limit the range of possible values of these signs for each class of aerospace defense. KPU 6 evaluates the hit of a point of the planes "route speed - height" and "vertical component of speed - height" with the current vertical component of speed, route speed and flight altitude of aerospace defense in the range of possible values of the corresponding planes for each of the recognized classes of aerospace defense. Thus, the classifier of the first level carries out preliminary recognition of the CTP class by trajectory features.

The results obtained in KPU 6 are sent to the second level classifier KVU 7, where a corrector for the majority is applied using the generalized voting algorithm [2, p. 26]. At this stage, a preliminary decision is made about the belonging of the EKR to a certain class, if it can be recognized by trajectory signs, or about the belonging of the EKR to a group of classes, the recognition within which will be carried out according to signal signs: longitudinal size, changes in the RCS and its averaged value, as well as correlation the dependence of the EPR value on the sounding frequency.

To assess the longitudinal dimension, the method developed by Professor Ya.D. Shirman, which consists in irradiating the target with a multifrequency signal with the subsequent analysis of the resulting frequency portrait of the target. The frequency portrait is the dependence of the target EPR on the frequency of the probing signal [2]. To determine the longitudinal size of an air object (AO) during incoherent multifrequency sounding with pulse-by-pulse frequency tuning of the RLM, the method of measuring the interval between frequencies is usually used.

The longitudinal dimension is calculated on the basis of the analysis of the amplitudes of target echo signals at each frequency received from the output of 5 BO 1 and obtained during multifrequency sounding.

As you know, one of the most common and easy-to-implement methods for radar determination of the longitudinal size of the EKO is a method in which the RLM emits a multifrequency signal [2], tuning the signal sounding frequency from pulse to pulse according to a predetermined periodic law. In this case, the distance between the frequencies determines the largest unambiguously measured longitudinal size of the air object and is calculated in accordance with the Kotelnikov theorem using the formula:

,

,

where L _max is the largest, unambiguously measured longitudinal dimension of the air object;

с - the speed of propagation of electromagnetic waves.

The smallest longitudinal size of the air object required for measurement determines the range of the RLM frequency tuning when a multi-frequency sounding signal is emitted, is determined by the formula:

,

,

where L _min is the smallest, unambiguously measured longitudinal dimension of an air object.

The number of radiated frequencies required for measuring the longitudinal dimension is determined by the formula:

Thus, for unambiguous radar measurement of targets in the most widespread range of longitudinal dimensions from 4 m (corresponds to aircraft missiles) to 50 m (corresponds to large-sized aircraft), a signal must be emitted and received at 26 frequencies. Moreover, as shown by modeling, for the required measurement accuracy, on average at each frequency, the signal-to-noise ratio should be at least 18 dB, which, with a regular circular method of viewing space in azimuth, is achieved only at small boundaries.

The construction of multi-band radar systems with two-stage measurement of the longitudinal dimension of the aerospace defense system can reduce the time spent on this and increase the measurement accuracy. Moreover, the greatest boundaries for the issuance of information about the target class and the probabilities of correct recognition can be achieved in dual-band radars of meter-decimeter or meter-centimeter wavelengths. In such radar systems, the detection and tracking of airborne objects is carried out by a VHF radar module. Large RCS values in this range provide long detection ranges for targets, especially subtle ones. When implementing sounding in this module at two frequencies with pulse-by-pulse frequency tuning, a rough estimate of the longitudinal dimension is carried out by calculating and averaging the frequency recognition feature: small air object - longitudinal dimension from 4 to 12 m, medium-sized air object - longitudinal dimension from 12 to 25 m, or large-sized air object - longitudinal size from 26 to 50 m. These operations are implemented in VCHPR 4 and BUCHPR 8, respectively.

A rough estimate of the longitudinal dimension allows you to select the optimal operating frequency range and frequency step for accurate measurement of the longitudinal dimension in a short-wavelength RLM with APAR and two-dimensional electronic scanning, which makes long-term contact with a target in the mode of a beam stopped on an air object. So, for a small-sized target, a large frequency tuning range with a large frequency step is selected, and for a large-sized target, on the contrary, a small frequency tuning range with a small frequency step. In both cases, the number of frequencies used to accurately measure the longitudinal dimension, and, accordingly, the time spent on this will be significantly reduced. The resulting economy of time resources allows the recognition of a larger number of aerospace objects during one survey, or allows using the saved time to implement other special modes that improve the quality of radar information. At the same time, due to the accurate measurement of the longitudinal dimension in one survey, large boundaries for the recognition of the aerospace defense classes are provided.

The values of the distance between frequencies, the range of frequencies and their number for accurate measurement of the longitudinal size of a small, medium-sized and large-sized air object are shown in Table 1.

The choice of a short-wavelength (decimeter or centimeter wavelength range) RLM for accurate measurement of the longitudinal dimension is due to the possibility of forming narrow antenna radiation patterns in it, both in the azimuthal and elevation planes, which minimizes the contact time with an air object at a fixed average signal-to-signal ratio. noise. In addition, RLM of decimeter and centimeter wavelength ranges provide greater accuracy of measurement of trajectory recognition features in comparison with RLM of meter range.

The choice of targets for accurate measurement of the longitudinal size is carried out in the UVVO 10, based on the information about the recognized classes and groups of classes, coming from the CWU 7, as well as on the basis of the value of the EKO priority coming from the fourth output of BO 1. This allows you to measure the longitudinal size of air objects, unrecognizable by trajectory signs, as well as the highest priority targets, in the event of a lack of RLM performance.

The amplitudes of the EKO echo signals obtained during sounding at the optimized RLM frequencies of the decimeter or centimeter wavelength range are fed to the BO 1 and are transmitted from its sixth output to the device for calculating the longitudinal size of the VCR 13.

The RCS of the aerospace defense is estimated on the basis of the data on the range and elevation angle of the target, the amplitude of its echo signal and the a priori dependence of the range of the target with RCS 1 m ² on the elevation angle received from the output of 7 BO 1.

In the case of using synchronous response noise, which are amplified copies of probing signals, false detection of targets occurs, as a result of which false traces are formed in the radial direction relative to the RLM, which leads to masking of real targets.

There is a known method of target recognition (RF patent No. 2549192 C1, IPC G01S 7/36, publ. 04/20/2015) [3], which indicates that based on the dependence of the EPR of the aerospace defense system on the range, it is possible to make a decision about a false target formed as a result of the action of the synchronous return interference.

To do this, in VEPR 5 at different ranges, the RCS is estimated using the well-known formula [4]:

,

,

where σ is the EPR value;

- мощность принятого сигнала;

- received signal power;

- мощность передатчика;

- transmitter power;

G is the gain of the transmitting (receiving) antenna;

λ is the RLM wavelength;

R - target range.

принимается решение об истинности цели. В противном случае принимается решение о ВКО как ложной цели (ракета-ловушка). При этом, если оценка ЭПР увеличивается, то ложная цель удаляется, а если оценка ЭПР уменьшается, то ложная цель приближается. Принятое решение поступает на ПК 15.Then in BRLTs 9 the obtained values are compared, and under the condition

a decision is made about the truth of the goal. Otherwise, a decision is made about aerospace defense as a false target (booby-trap). In this case, if the RCS estimate increases, then the false target is removed, and if the RCS estimate decreases, then the false target approaches. The decision made is sent to PC 15.

However, due to the jagged shape of the secondary radiation pattern, fluctuations of the radar signals appear. To reduce the harmful effect of fluctuations σ _c and increase the probability of correct recognition, it is proposed to apply a method based on the use of differences in the correlation coefficients of signal amplitudes with a multifrequency sounding signal. In this case, at first, the relative difference of signals (ρ is a sign) is processed, then the result obtained is compared with the corresponding threshold.

,

,

where U ₁ , U ₂ - signal amplitudes at frequencies ƒ ₁ , ƒ ₂ .

за счет того, что коэффициент взаимной корреляции сигналов для крупноразмерной цели составляет 0,2, для среднеразмерных целей 0,5<ρ<0,75, а для ракет-ловушек ρ>0,9. Данное соотношение выполняется при условии 5-6 независимых оборотов обзорного РЛМ.For example, with a carrier frequency separation of Δƒ = 6 MHz, it is possible to determine the type of VKO with the probability of correct recognition

due to the fact that the cross-correlation coefficient of signals for a large-sized target is 0.2, for medium-sized targets 0.5 <ρ <0.75, and for booby-trap missiles ρ> 0.9. This ratio is fulfilled under the condition of 5-6 independent revolutions of the survey RLM.

In this case, based on the calculated frequencies in the BKPR 8 and the values of the EPR in the BUEPR 12, the correlation feature of recognition is determined in the BKPR 14 by the formula:

where M is the number of revolutions of the survey RLM.

In this case, information from both previous and subsequent calls to the target is used to calculate ρ.

The first input of the parametric classifier PC 15 receives the results of the generalized voting from the KVU 7 block, the second input receives the calculated longitudinal dimension, the third input from the BKPR 14 receives data on the averaged RCS of the VKO and the correlation dependence of the RCS on the sounding frequency, the fourth input receives information about false targets from BRLTs 9, identified by changing the EPR. Here the final decision on the class of aerospace defense is made, taking into account the signal signs.

The parameters of KPU 6, KVU 7 and PC 15 are selected in accordance with the a priori distributions of signs of recognition of classes of CTP, as well as on the basis of measurement errors of signs and requirements for the probability of correct recognition of classes of CTP.

Signal recognition signs are used in the proposed device to increase the probability of correct recognition of the most important classes of detected targets, such as aircraft of tactical and strategic aviation, as well as decoys.

Thus, to obtain a technical result, namely, to expand the alphabet of VKO classes and increase the probability of correct recognition to an acceptable quality in a short time (no more than 6 calls to VKO), possibly by adding a BRLTs and BKPR with new links to the prototype, while adding the existing recognition algorithm of the procedure for determining the class of air defense by assessing the change in EPR and by the correlation feature is technically feasible.

The proposed technical solution is industrially applicable, since it is based on known technologies of adaptive interaction of radio electronic equipment and is intended for radar recognition of classes of aerospace objects in multi-band radar systems.

List of references.

1. RF patent No. 2665032 C2, IPC G01S 13/52 "A device for recognizing aerospace objects in dual-band radar systems with active phased antenna arrays (AFAR)", publ. 27.08.2018

2. Shirman A.D. and others. "Methods of radar recognition and their modeling." Foreign radio electronics, 1996, No. 11.

3. RF patent No. 2549192 C1, IPC G01S 7/36 "Method of target recognition", publ. 20.04.2015

4. Skolnik M. Handbook of radar, volume 1. M .: "Soviet radio", 1976, pp. 356-395.

Claims (1)

A device for radar recognition of classes of aerospace objects in a multi-band radar complex with phased antenna arrays (PAR), containing a radar information processing unit (BO), which is configured with the possibility of generalized secondary processing of radar information, a vertical velocity component (VVS), a route speed computer (VTS), the calculator of the frequency recognition feature (VCHPR), the averaging unit of the frequency recognition feature (FUCHR), the calculator of the effective scattering area (VEPR), the averaging unit of the effective scattering area (ECEP), the first level classifier (KPU), the second level classifier (KVU) ), a device for selecting air objects (UVVO), a device for selecting operating frequencies (UHRCH), a longitudinal size calculator (VPR), a parametric classifier (PC), as well as an added false target recognition unit (BRLTs) and a recognition correlation attribute unit (BKPR), while the first, the second and third outputs of the BO are connected, respectively, with the first input, through the VVSS with the second input and through the VTS with the third input of the KPU, the second output of the VVSS is connected to the first input of the VTS, and the output of the KPU is connected to the input of the KVU, the first and second outputs of the KVU are connected respectively, with the first input of the PC and with the first input of the UVVO, the second input of the UVVO is connected to the fourth output of the BO, and the third input is connected to the output of the UVRCH, the first input of which is connected to the second output of the UVVO, the first output of which is the first output of the device, and the second input is through the VCPR, connected in series with the fifth output of the BO and the first output of the BUCHPR, the second output of which is connected to the first input of the BKPR, the sixth output of the BO through the VLT is connected to the second input of the PC, and the seventh output of the BO through the series-connected VEPR is connected to the BRLC, the first output of which is through a series-connected BUEPR with the second input of the BKPR, and the second output is connected to the fourth input of the PC, the BKPR is connected to the third input of the PC, the output of which is the second output of the device.

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