RU2828475C1 - Surveillance radar station recognition device - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: invention relates to radio engineering and can be used in radio monitoring means. In the recognition device, the fact of rotation of the antenna-feeder system of the radar station is additionally established and complexed with the result of determining the type of modulation, corresponding to the radar station signals, at the output of the N channel maximum selection circuit.

EFFECT: high probability of recognizing a radar station operating in survey mode.

1 cl, 2 dwg

Description

The invention relates to radio engineering and can be used in radio monitoring means, as well as other similar means and systems in which the type of modulation of radio signals of radio emission sources (RES) is determined in the interests of their subsequent recognition.

A device for determining the type of modulation of radio signals is known [1], which includes a series-connected input bandpass filter, parallel-connected frequency, phase and amplitude detectors, the outputs of which are combined with a series-connected output bandpass filter and a device for displaying and listening to the detected signal of this device, a sequential selection of the demodulators available in the receiving equipment is carried out and a decision on the type of modulation is made on the basis of, for example, the reproduction of speech from the output of the corresponding demodulator without distortion, the presence of a television signal, and for digital signals the presence of semantic information when selecting the appropriate demodulator/decoder combination.

The disadvantage of the device is the low probability of recognizing a radar station (RLS) operating in the survey mode, and also the fact that the decision is usually made by the operator using the visual-auditory control method.

The closest in technical essence and achievable technical result is a device for determining the type of modulation [2] (prototype), containing a series-connected bandpass filter (BF) with a passband matched to the signal spectrum, N processing channels, each of which includes a series-connected first multiplier, integrator, first subtractor (S), a series-connected first unit for calculating the root mean square (RMS), a second multiplier, a divider, wherein the second input of the divider is connected to the output of the first S, and a reference signal of a given type is fed to each of the second inputs of the first multipliers, combined with the inputs of the first units for calculating the RMS in each of the N processing channels, a second unit for calculating the RMS, wherein the output of the second unit for calculating the RMS is connected to the second input of the second multiplier, and its input is combined with the first inputs of the first multipliers and the output of the BF, parallel-connected series-connected third multipliers and integrators, the outputs of which are connected to the first and second inputs, respectively, of the second S, the output of which is connected to the combined second inputs of the first VU and the comparison device (CD), the output of which is connected to the combined second inputs of the switches, the first inputs of which are connected to the outputs of the dividers in each of the N processing channels, wherein the second input of the comparison device is combined with the first input of the second VU, and the first inputs of the third multipliers are combined with the output of the PF, wherein the second input of one of the third multipliers is combined with the inputs of the second RMS calculation units and the output of the PF, and the second input of the other third multiplier is connected to the input of the PF and the input of the device, the outputs of the switches are connected to the corresponding inputs of the N-channel maximum selection circuit (MSC).

The disadvantage of the device is the low probability of recognizing a radar operating in the survey mode.

The technical result of the invention is an increase in the probability of recognizing a radar operating in a survey mode by automatically establishing the fact of rotation of the directivity pattern (DP) of the antenna-feeder system (AFS) of the radar by identifying the periodicity of the change in the spectrum envelope of the radar signal and combining it with the result of determining the type of modulation corresponding to the radar signals at the output of the N-channel SVM.

The technical result is achieved in that a known device comprising series-connected PFs with a bandwidth matched to the signal spectrum, N processing channels, each of which includes a series-connected first multiplier, integrator, first VU, a series-connected first RMS calculation unit, a second multiplier, a divider, wherein the second input of the divider is connected to the output of the first VU, and a reference signal of a given type is supplied to each of the second inputs of the first multipliers combined with the inputs of the first RMS calculation units in each of the N processing channels, a second RMS calculation unit, wherein the output of the second RMS calculation unit is connected to the second input of the second multiplier, and its input is combined with the first inputs of the first multipliers and the output of the PF, parallel-connected series-connected third multipliers and integrators, the outputs of which are connected to the first and second inputs, respectively, of the second VU, the output of which is connected to the combined second inputs of the first VU and the first US, the output of which is connected to the combined second inputs of switches, the first inputs of which are connected with the outputs of the dividers in each of the N processing channels, wherein the second input of the first control unit is combined with the first input of the second control unit, and the first inputs of the third multipliers are combined with the output of the PF, wherein the second input of one of the third multipliers is combined with the inputs of the second RMS calculation units and the output of the PF, and the second input of the other third multiplier is connected to the input of the PF and the input of the device, the outputs of the switches are connected to the corresponding inputs of the N-channel SVM, wherein Additionally, a series-connected register for storing the numbers of modulation types corresponding to the radar signals and used, among others, as reference signals for determining the type of modulation, a second control unit, a fourth multiplier are introduced, wherein the first input of the second control unit is connected to the output of the N-channel SVM, a device for establishing the fact of rotation of the DN, the input of which is connected to the output of the PF, and the output to the second input of the fourth multiplier, the output of which is the output of the device.

The additionally introduced device for establishing the fact of rotation of the DN includes a series-connected analog-to-digital converter (ADC), a multiplier, a digital low-pass filter (DLPF), a first fast Fourier transform (FFT) processor, a spectrum maximum extraction unit (SMU), an accumulator, a second FFT processor, a first threshold device (DD), a pulse counter, a second DD, wherein the ADC input is connected to the FD output, and the output of the second DD is connected to the second input of the fourth multiplier, in addition, the second input of the second DD is connected to the output of the unit storage register, the second input of the first DD is connected to the output of the threshold level storage register, and the second input of the multiplier is connected to the output of the reference generator (RG).

The essence of the invention lies in the fact that an additionally introduced device for establishing the fact of rotation of the DN includes series-connected ADC, a multiplier, a low-pass filter, a first FFT processor, a pulse counter, a storage device, a second FFT processor, a first PU, a pulse counter, a second PU, wherein the ADC input is connected to the PF output, and the output of the second PU to the second input of the fourth multiplier, in addition, the second input of the second PU is connected to the output of the unit storage register, the second input of the first PU is connected to the output of the threshold level storage register, and the second input of the multiplier is connected to the output of the OG, ensures the conversion of the input process in the form of an additive mixture of the useful signal and Gaussian noise from the PF output into a time sequence of samples, and the multiplier in combination with the OG ensures their transfer to the region of the zero intermediate frequency (IF) with subsequent low-pass (LP) filtering and conversion of the time sequence of samples of the input process into the spectral region. After that, the newly introduced BVMS ensures the selection of the maximum value of the spectrum, and the accumulator performs a sequential recording of all spectrum maxima coming from the BVMS. As a result, in the case of radar operation in the survey mode, the signal at the accumulator output will be a quasi-harmonic oscillation caused by a change in the spatial position (rotation) of the radar AFS RP and, accordingly, a periodic change in the level of the signal spectrum envelope. Consequently, the spectrum of such a quasi-harmonic oscillation will be formed by one spectral component, which is a sign of the radar AFS RP rotation. Automatic establishment of the fact of the radar AFS RP rotation is based on a comparison of the amplitude of the spectral component of the obtained quasi-harmonic oscillation with a given threshold level and counting the number of excess pulses. If the pulse is single, a decision is made to establish the fact of the RP rotation, otherwise - about the absence of rotation. The obtained result in the form of a logical unit (if the fact of rotation is established) is combined with the result of comparison in the second control unit of the modulation type number at the output of the SVM with the numbers of modulation types recorded in the storage register, corresponding to the radar signals. If the decisions are positive in both cases, a decision is made to recognize the surveillance radar, which is how the technical result is achieved.

Therefore, the introduced blocks provide automatic establishment of the fact of rotation of the DN of the AFS of the surveillance radar by identifying the periodicity of the change in the envelope of the spectrum of its signal and combining it with the result of determining the type of modulation corresponding to the radar signals at the output of the N-channel SVM, thereby increasing the probability of recognition of a radar operating in the surveillance mode.

Fig. 1 shows a functional diagram of the device for recognizing a surveillance radar, and Fig. 2 shows a functional diagram of the device for establishing the fact of rotation of the DN.

The surveillance radar recognition device consists of a PF 1, N processing channels 12.n, where n=1, 2, …, N, two third multipliers 2.3, a fourth multiplier 2.4, two integrators 3, a second VU 5.2, a first comparison device 7.1, a second comparison device 7.2, N switches 8, an N-channel SVM 9, a device for establishing the fact of rotation of the DN 10, a recorder for storing the numbers of modulation types 11.

Each N-th processing channel 12.n consists of the first multiplier 2.1, the second multiplier 2.2, the integrator 3, the first block for calculating the SLS 4.1, the second block for calculating the SLS 4.2, the first VU 5.1, and the divider 6.

The device for establishing the fact of rotation of the DN 10 consists of
ADC 10.1, multiplier 10.2, OG 10.3, DLPF 10.4, first FFT processor 10.5, BVMS 10.6, accumulator 10.7, second FFT processor 10.8, first PU 10.9, threshold level storage register 10.10, pulse counter 10.11, second PU 10.12, unit storage register 10.13.

The purpose of the device elements is clear from their names and all elements can be made on the basis of known industrially produced radio engineering elements.

The reference generator can be made according to the diagram given in (see, for example, in the book Radio receiving devices: Textbook for universities / Edited by N.N. Fomin. - 3rd edition, stereotype. - M.: Goryachaya Liniya - Telecom, 2007, Fig. 7.20, p. 329).

Integrators, multipliers, VU, PU, RMS calculation units, comparison devices, modulation type number storage register, unit storage register, N-channel SVM, LFPU, BVMS, FFT processors, accumulator and pulse counter can be implemented on programmable logic integrated circuits (FPGA), digital signal processors (DSP) (for example, FPGA Cyclone III series FPGA from ALTERA, DSP TS101S from Analog Devices and DDC GC4016).

The surveillance radar recognition device comprises series-connected PF 1 with a passband matched to the signal spectrum, N processing channels 12.n, each of which includes a series-connected first multiplier 2.1, integrator 3, first VU 5.1, series-connected first RMS calculation unit 4.1, second multiplier 2.2, divider 6, wherein the second input of divider 6 is connected to the output of the first VU 5.1, and a reference signal of a given type is fed to each of the second inputs of the first multipliers 2.1, combined with the inputs of the first RMS calculation units 4.1 in each of the N processing channels 12.n, a second RMS calculation unit 4.2, wherein the output of the second RMS calculation unit 4.2 is connected to the second input of the second multiplier 2.2, and its input is combined with the first inputs of the first multipliers 2.1 and the output of the PF 1, parallel-connected series-connected third multipliers 2.3 and integrators 3, the outputs of which are connected to the first and second inputs, respectively, of the second VU 5.2, the output of which is connected to the combined second inputs of the first VU 5.1 and the first US 7.1, the output of which is connected to the combined second inputs of the switches 8, the first inputs of which are connected to the outputs of the dividers 6 in each of the N processing channels, wherein the second input of the first US 7.1 is combined with the first input of the second VU 5.2, and the first inputs of the third multipliers 2.3 are combined with the output of the PF 1, wherein the second input of one of the third multipliers 2.3 is combined with the inputs of the second RMS calculation units 4.2 and the output of the PF 1, and the second input of the other third multiplier 2.3 is connected to the input of the PF 1 and the input of the device, the outputs of the switches 8 are connected to the corresponding inputs of the N-channel SVM 9, according to the invention, a series-connected register for storing the numbers of modulation types 11 corresponding to the signals is additionally introduced RLS and used, among others, as reference signals for determining the type of modulation, the second US 7.2, the fourth multiplier 2.4, wherein the first input of the second US 7.2 is connected to the output of the N-channel SVM 9, the device for establishing the fact of rotation of the DN 10, the input of which is connected to the output of the PF 1, and the output to the second input of the fourth multiplier 2.4, the output of which is the output of the device.

The additionally introduced device for establishing the fact of rotation of the DN 10 includes series-connected ADC 10.1, multiplier 10.2, low-frequency filter 10.4, first FFT processor 10.5, BVMS 10.6, accumulator 10.7, second FFT processor 10.8, first PU 10.9, pulse counter 10.11, second PU 10.12, wherein the input of ADC 10.1 is connected to the output of PF 1, and the output of the second PU 10.12 to the second input of the fourth multiplier 2.4, in addition, the second input of the second PU 10.12 is connected to the output of the unit storage register 10.13, the second input of the first PU 10.9 is connected to the output of the threshold level storage register 10.10, and the second input of the multiplier 10.2 is connected to the output of the OG 10.3.

The operation of the surveillance radar recognition device differs from the operation of the modulation type determination device [2], taken as a prototype, in that, when the device starts operating, an additive mixture of the useful signal is sent to the first input of the additionally introduced device for establishing the fact of rotation of the DN 10 simultaneously with the inputs of the N processing channels 12.n and noise from the output of PF 1 in the form , where it is immediately fed to the input of ADC 10.1. In ADC 10.1, the input process is converted into an additive mixture of the useful signal and noise into a time sequence of readings, which has the form , Where - sample number. From the ADC output 10.1 the time sequence of samples using the multiplier 10.2 and the OG 10.3 are transferred to the zero IF region with subsequent low-pass filtering using the LFPF 10.4. After this, the time sequence of readings input process to the zero IF is fed to the input of the first FFT processor 10.5, where it is converted from the time domain to the spectral domain. From the output of the first FFT processor 10.5, the set of spectral samples of the input process , which takes the form , where M is the number of spectral samples, is fed to the input of the BVMS 10.6, where the maximum level is determined from all spectral components of the given sample, and then this value is recorded in accumulator 10.7. After that, for the next sample of spectral readings, the procedure is repeated and, thus, in accumulator 10.7, a sequential recording of the maximum spectrum levels from the following samples of spectral readings is carried out . As a result, in the case of radar operation in the survey mode, the signal at the output of accumulator 10.7 will form a voltage representing a quasi-harmonic oscillation caused by a change in the spatial position of the radar AFS pattern and, accordingly, a periodic change in the level of the envelope of the signal spectrum at the output of the first FFT processor 10.5. In this case, the spectrum of such a quasi-harmonic oscillation will be formed by one spectral component, which will be a sign of rotation of the radar AFS pattern. For this purpose, the voltage from the output of accumulator 10.7 is fed to the input of the second FFT processor 10.8, from the output of which the spectrum of the output voltage of accumulator 10.7 is fed to the input of the first PU 10.9, where the spectrum level is compared with the specified threshold level coming from the output of the threshold level storage register 10.10. If the threshold is exceeded in the first PU 10.10, then a pulse with a logical one level is fed from its output to the input of the pulse counter 10.11, which counts their number. If the spectrum of the quasi-harmonic oscillation at the output of the second FFT processor 10.8 is formed by one spectral component, which is a sign of the rotation of the AFS radar pattern, then one pulse will come to the pulse counter 10.11, otherwise a greater number. Therefore, from the output of the pulse counter 10.11, the accumulated number of pulses is fed to the first input of the second PU 10.12, in which it is compared with the unit coming from the output of the unit storage register 10.13. If the number of pulses from the output of the pulse counter 10.11 is equal to one, then a decision is automatically made to establish the fact of rotation of the AFS radar DN and the voltage with the logical one level is fed to the output of the device for establishing the fact of rotation of the DN 10 and, accordingly, to the second input of the fourth multiplier 2.4. In this case, the number of the modulation type, determined in accordance with the algorithm described in the prototype device, is fed from the output of the N-channel SVM to the first input of the second US 7.2. The numbers corresponding to the typical types of modulations of surveillance radars are sequentially fed to the second input of the second control unit 7.2 from the output of the register for storing the numbers of the types of modulation 11 and compared with the number of the type of modulation from the output of the N-channel SVM 9. If they coincide, a logical one signal is fed from the output of the second control unit 7.2 to the first input of the fourth multiplier 2.4 and, accordingly, if there is a similar signal at its second input, a logical one signal is fed to the output of the device, which indicates an automatic decision to recognize the surveillance radar, thereby increasing the probability of recognizing a radar operating in the surveillance mode, which achieves the stated technical result.

Sources of information

1. Rembovsky A.M., Ashikhmin A.V., Kozmin V.A. Radio monitoring: tasks, methods, tools / edited by A.M. Rembovsky. – M.: Goryachaya Liniya-Telecom, 2006. – pp. 202, 208.

2. Patent No. 2796588 Russian Federation, IPC H04B 1/10 (2006.01). Device for determining the type of modulation: No. 2022121362: declared 03.08.2022, published 26.05.2023 / Bubenshchikov A.A., Dudarikov O.B., Arkhipov R.B., Sidorenko I.A., Yatsenko B.M., Neino A.A. – 11 p. : ill. – Text: direct.

3. Radio receivers: Textbook for universities / Edited by N.N. Fomin. – 3rd edition, stereotype. – M.: Goryachaya Liniya – Telecom, 2007, fig. 7.20, p. 329.

Claims (1)

A surveillance radar recognition device comprising a series-connected bandpass filter with a passband matched to the signal spectrum, N processing channels, each of which includes a series-connected first multiplier, an integrator, a first subtractor, a series-connected first RMS value calculation unit, a second multiplier, a divider, wherein the second input of the divider is connected to the output of the first subtractor, and a reference signal of a given type is supplied to each of the second inputs of the first multipliers, combined with the inputs of the first RMS value calculation units in each of the N processing channels, a second RMS value calculation unit, wherein the output of the second RMS value calculation unit is connected to the second input of the second multiplier, and its input is combined with the first inputs of the first multipliers and the output of the bandpass filter, parallel-connected series-connected third multipliers and integrators, the outputs of which are connected to the first and second inputs, respectively, of the second subtractor, the output of which is connected to the combined second inputs of the first subtractors and the first a comparison device, the output of which is connected to the combined second inputs of switches, the first inputs of which are connected to the outputs of the dividers in each of the N processing channels, wherein the second input of the first comparison device is combined with the first input of the second subtractor, and the first inputs of the third multipliers are combined with the output of the bandpass filter, wherein the second input of one of the third multipliers is combined with the inputs of the second units for calculating the root mean square value and the output of the bandpass filter, and the second input of the other third multiplier is connected to the input of the bandpass filter and the input of the device, the outputs of the switches are connected to the corresponding inputs of the N-channel maximum selection circuit, characterized in that a register for storing modulation type numbers, a second comparison device, a fourth multiplier are additionally introduced, connected in series, wherein the first input of the second comparison device is connected to the output of the N-channel maximum selection circuit, a device for establishing the fact of rotation of the directional pattern, the input of which is connected to the output of the bandpass filter, and the output to the second input of the fourth multiplier, the output of which is the output of the device, wherein the device for establishing the fact of rotation of the directional pattern includes series-connected an analog-to-digital converter, a multiplier, a digital low-pass filter, a first fast Fourier transform processor, a spectrum peak extraction unit, an accumulator, a second fast Fourier transform processor, a first threshold device, a pulse counter, a second threshold device, having connections between themselves: the input of the analog-to-digital converter is connected to the output of the bandpass filter, and the output of the second threshold device is connected to the second input of the fourth multiplier, in addition, the second input of the second threshold device is connected to the output of the unit storage register, the second input of the first threshold device is connected to the output of the threshold level storage register, and the second input of the multiplier is connected to the output of the reference generator.