RU2606634C2 - Method of ultra broadband signal detecting - Google Patents

Method of ultra broadband signal detecting Download PDF

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RU2606634C2
RU2606634C2 RU2015105312A RU2015105312A RU2606634C2 RU 2606634 C2 RU2606634 C2 RU 2606634C2 RU 2015105312 A RU2015105312 A RU 2015105312A RU 2015105312 A RU2015105312 A RU 2015105312A RU 2606634 C2 RU2606634 C2 RU 2606634C2
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signal
band
correlation coefficient
signals
pass filters
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RU2015105312A (en
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Евгения Александровна Алисевич
Павел Владимирович Закалкин
Игорь Юрьевич Санин
Юрий Иванович Стародубцев
Петр Юрьевич Стародубцев
Елена Валерьевна Сухорукова
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Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Санкт-Петербургский государственный торгово-экономический университет"
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/28Details of pulse systems
    • G01S7/285Receivers

Abstract

FIELD: electricity; radio engineering.
SUBSTANCE: invention relates to means for electronic equipment radio monitoring and can be used for detecting illegally installed radio-electronic devices using pulsed ultra-broadband signals. In the method of broadband signal detecting ultra-wideband signal is supplied into plurality of m parallel connected band-pass filters with mutually adjoining band passes of the same value, wherein of band pass width of band-pass filters is much less than signal spectrum width. i pairs of band-pass filters are randomly selected, signals from the outputs of each of which are transferred to intermediate frequency, amplitude detected and digitized and quantized by level, converting them to digital form, after which correlation coefficient between received digital signals for each pair of band-pass filters is calculated. Correlation coefficient calculated value is compared with threshold value with correlation coefficient exceeding threshold value, decision is made on signal presence, correlation coefficient calculated values are recorded into cells, each of which corresponds to numbers of band-pass filters, symmetrical matrix, in which number of columns and rows is equal to number of m band-pass filters, derived values are compared, cell with maximum value of correlation coefficient is determined and main signal frequency is determined.
EFFECT: technical result consists in detection of radio electronic devices using ultra-broadband signals in predetermined frequency band, under conditions of signals parameters uncertainty, as well as determination of main frequency of detected radio electronic frequencies.
1 cl, 4 dwg

Description

The invention relates to radio monitoring of electronic equipment and can be used to detect unauthorized installation of electronic devices using pulsed ultra-wideband (UWB) signals.

Currently, the following definitions of UWB signal exist:

1. Under UWB signal understand a signal whose broadband index satisfies the condition (O. Lazorenko, L. Chernogor. Ultra-wideband signals and physical processes. Basic concepts, models and description methods [Electronic resource]. URL: http://www.twirpx.com / file / 472895 /? rand = 7383906 (accessed February 19, 2013)):

Figure 00000001

where the broadband indicator is given by the ratio:

Figure 00000002

where f 0 , f min , f max - the average, minimum and maximum frequencies of the spectral density function (FSP) of the one-dimensional Fourier transform (OPF) S (f) of this signal s (t); Δf = f max -f min is the signal bandwidth.

2. According to the definition introduced by the US Department of Defense Department of Advanced Military Research and Development, the μ min = 0.25, af min and f max should be found from the level of -20 dB of FSP reduction relative to the main maximum.

3. According to the definition of the US Federal Commission, which appeared in 2002, it is proposed to consider μ min = 0.20, af min and f max to be determined by the level of -10 dB, and the frequency band occupied by the UWB signal should satisfy the condition Δf≥500 MHz (Sudakov A. Signals used in UWB radio systems [Electronic resource]. URL: http://www.sanechka.nightmail.ru/my_articles/2005_ 1 .pdf (accessed February 19, 2013))

Signals that can be used in UWB radio systems include:

- Gaussian impulses;

- radio pulses;

- Hermite impulses;

- chaotic signals;

- linear frequency-modulated signals;

- multi-frequency signals (Lazorenko O., Chernogor L. Ultra-wideband signals and physical processes. Methods of analysis and application. [Electronic resource] .URL: http://www.ri.kharkov.ua/journal/Papers/Paper568.pdf (date appeals on February 19, 2013))

The use of UWB signals with a very short duration (of the order of 1 nsec or less) and a large duty cycle for transmitting information over a radio channel gives the following advantages over signals with a narrow frequency band:

- low average radiated power, which usually does not exceed several tens of milliwatts and is determined by the range and speed of information transfer;

- covert operation of the communication line due to the low spectral power density per unit frequency band; electromagnetic compatibility with narrowband systems operating in the same frequency band;

- high speed information transfer;

- effective fight against multipath propagation due to the temporary selection of direct and re-reflected signals or correlation reception;

- minimum radio frequency circuits in the receiver / transmitter (lack of high-frequency generators, mixers, multipliers, etc.);

- simplicity of design (I.J. Immoreev, A.A. Sudakov, "Ultra-Wideband Interference Resistant System for Secure Radio Communication with High Data Rate", ICCSC02, St. Petersburg, Russian Federation, June 2002).

This leads to the possibility of using these methods to hide the radiation of means of covert information retrieval and, accordingly, to complicate the search for radio channels of means of covert information retrieval.

Communication systems using ultra-wideband signals are described in a number of articles and patents.

Examples are UWB devices for a pulsed communication system protected by US patents: (US 4,641,317 Spread Spectrum Radio Transmission System. Larry W. Fullerton. 12/03/84; US 5677927 Ultra wide - Band Communication System and Method. Larry W. Fullerton; Ivan A. Cowie. 10/14/1997; US 5687169 Full Duplex Ultra wide - Band Communication System and Method. Larry W. Fullerton 11/24/1997). These pulsed radio systems use one or more pulse subcarriers to transmit information. A pulsed radio receiver uses a cross-correlator that convolves a similar input signal with a reference signal, consisting of one hundred fifty to two hundred pulses synchronized in time with a known transmitter code.

However, this imposes restrictions on the level of distortion of the shape of the received signal, since when the UWB signal propagates, its shape changes depending on the distance of the transceiver. Due to the wide frequency band and ultra-short pulse duration, the requirements for synchronization accuracy in these systems are unusually high. In these well-known UWB systems, synchronization and auto-tuning signals are interconnected with the main information signals at the same energy level, and since the spectral density of all signals is at the noise level, the system is significantly susceptible to malfunctions.

The disadvantage can also be attributed to the need for comparison with the reference signal, a priori knowledge of the signal parameters, which is impossible in the case of the search for means of tacit information retrieval.

A more modern system is known (US 6925108. Ultrawide bandwidth system and method for fast synchronizaton. Timothy R. Miller. 08/02/2005). The method for identifying the phase of the input UWB signal is as follows: the received pulses and pulses with different time intervals between them, which correspond to individual time intervals of the reference code sequence, are fed to the multichannel correlator. If any specified interval coincides (phase interval), one of the correlators forms the first maximum. At the next coincidence in the second phase interval, the second correlator forms a second maximum. If the second maximum is higher than the first maximum, then the decision to start the reference pulse sequence is applied and the system enters into synchronism. The disadvantages include the operability of synchronization of this communication system only with a large signal / noise ratio at the input of the receiving device.

The disadvantage can also be attributed to the need to know the reference code sequence, a priori knowledge of the signal parameters, which is impossible in the case of searching for means of secret reading of information.

A patent is known (US 6925109. Method and system for fast acquisition of ultra-wideband signals. James L. Richards, Mark D. Roberts. 08/02/2005), the essence of the method in which is to use any part of the multipath propagation of a code sequence of a pulsed radio signal. Due to the increased pulsed flux of the multipath radio signal, it becomes possible to correlate with the standard pulsed flux, and when they coincide, the system enters into synchronism.

The disadvantage of this system is the inoperability in the mobile version, since the multipath condition unexpectedly changes depending on the range and relative position of the receiver and transmitter, as well as the need for processing with an exemplary pulse stream, a priori knowledge of the signal parameters, which is excluded in the case of searching for means of secret reading of information.

A patent is known (RU 2315424. A communication system with a high speed information transmission by ultra-wideband signals. Bondarenko VV, Kyshtymov GA, Bondarenko VV, Kyshtymov SG 20.01.2008), the essence of the search and detection of a signal in which consists in a twofold transmission of a clock signal, consisting of a pulsed broadband signal and a harmonic signal.

The disadvantage of this system is the need to know the main frequency of the system, the need to know the synchronization sequence, a priori knowledge of the signal parameters, which is impossible in the case of finding means for secret reading of information.

Closest to the claimed technical solution is a communication system (device): (P.A. Storozhev, A.S. Grigoriev WIRELESS COMMUNICATION SYSTEM WITH A SMALL SIGNAL / NOISE RELATIONSHIP, Proceedings of TSTU: collection of scientific articles by young scientists and students / Tamb. technical university - Tambov, 2007. - Issue 20., p. 141), taken as a prototype.

This system implements the method of autocorrelation reception of wideband noise-like signals, which consists in the fact that the received signal is multiplied with its copy delayed by time T, the time T coincides with the repetition period of the transmitted broadband noise-like signal. The result is averaged over a time equal to the duration (n-1) of the signal elements, where n is the number of transmitted repeating elements during the duration of the bit. Based on the result of averaging, a decision is made on the presence or absence of a signal.

The peculiarity of this method is that if only random noise is present at the input of the receiver, then the output will be a result proportional to the value of the noise autocorrelation function with a shift time equal to T, the mathematical expectation of this result is zero. If, in addition to noise, a useful signal is present at the input of the receiver, the voltage at the output of the receiver will be proportional to the energy of this signal during the averaging time. The accumulation of signal energy allows its detection, even if the level does not exceed noise.

When constructing a communication system, two branches were used to detect (detect) and distinguish logical signals 0 and 1, tuned to noise-like signals with different repetition periods T1 and T2, respectively.

The disadvantage of the prototype is the need for a priori knowledge about the duration of the transmitted signal, its repetition periods.

The claimed technical solution is free from this drawback.

The technical result of the claimed invention is the detection of unauthorized installation of electronic devices using ultra-wideband signals in a predetermined frequency range under conditions of uncertainty of the signal parameters, as well as determining the main frequency of operation of the NUEU.

The technical result is achieved due to the fact that in the known method for detecting an ultra-wideband signal, which consists in receiving electromagnetic signals in a predetermined frequency range, transferring them to an intermediate frequency, isolating the spectral envelope, converting them to digital form, for which the signals are sampled by time and quantized by levels, in addition, the entire predetermined frequency range is further divided into m mutually adjacent subbands (filter channels) of the same magnitude, and the other of the sub-range (filter channel) is much smaller than the signal spectrum width Δw pf << Δw c , according to a random law from m filter channels i pairs of channels are selected, the correlation coefficient R s between the channels in each selected pair is calculated, the calculated value of the correlation coefficient R s with then the threshold value R, with a coefficient of correlation exceeding a threshold value (R s> R pore) decide whether a signal is recorded value R s calculated correlation coefficient in the matrix and compare them, define channel number max The maximum value of the correlation coefficient R s max, determined by the basic frequency signal f est.

The analysis made it possible to establish that analogues that characterize the totality of features that are identical to all the features of the claimed method are absent, which indicates the compliance of the claimed method with the condition of patentability “novelty”.

Search results for known solutions in this and related fields of technology in order to identify features that match the distinctive features of the claimed object from the prototype showed that they do not follow explicitly from the prior art. The prior art also did not reveal the popularity of the impact provided by the essential features of the claimed invention, the transformations on the achievement of the specified technical result. Therefore, the claimed invention meets the condition of patentability "inventive step".

"Industrial applicability" of the method is due to the presence of the element base, on the basis of which devices that implement this method can be made.

The claimed system is illustrated by drawings:

FIG. 1 is a generalized algorithm of the proposed method for detecting signals;

FIG. 2 is a generalized structural diagram of a method for detecting UWB signal;

FIG. 3 - spectrum of a short radio pulse;

FIG. 4 - matrix of correlation coefficient values

The claimed method is as follows:

Signals from unauthorized installed electronic devices of the systems of secret reading of information should be considered as random processes in the conditions of unknown parameters.

To detect such signals, autocorrelation reception methods are usually used when the reference voltage is generated from the received signal by various transformations, determined by the type of the received signal, in particular from the signal itself, delayed in the delay line (P.A. Storozhev, A.S. Grigoriev WIRELESS COMMUNICATION SYSTEM WITH A SMALL SIGNAL / NOISE RELATIONSHIP, Proceedings of TSTU: collection of scientific articles by young scientists and students / Tambov State Technical University - Tambov, 2007. - Issue 20., p. 141; L.F. Montenegro "Remote sensing of the atmosphere s and space:.. Textbook - H .: Kharkiv VN Karazin, 2009, p 181-182)..

To detect UWB signal with a priori unknown parameters, it is proposed to apply a similar idea, only use one of the filtering channels in the selected pair as the reference channel. This is due to the properties of ultra-wideband signals (Radzievsky VG, Trifonov PA “Processing of ultra-wideband signals and interference.” - M .: Radio Engineering, 2009, p. 28-40) and the laws governing the conversion of ultra-wideband signals by band-pass filters (Sosulin Yu.G. “Theoretical Foundations of Radar and Radio Navigation.” - M.: Radio and Communications, 1992, p. 43-48).

The algorithm of the proposed method is as follows (Fig. 1, Fig. 2):

An ultrawideband signal is supplied to all m parallel-coupled bandpass filters PF (blocks 1, 2 of FIG. 1, blocks PF 1 to PF m of FIG. 2), with mutually adjacent passbands of the same magnitude, and the bandwidth of the band-pass filters is much smaller than the spectrum width signal Δw pf << Δw c . In order to reduce the detection time, switching between the outputs of the bandpass filters PF and the inputs of the frequency converters IF (bl PF 1 - PF m and IF 1 - IF m Fig. 2) is proposed to carry out the switch (Uryadnikov Yu.F., Adzhemov SS " Ultrawideband communication. Theory and application. ”- M .: SOLON-Press, 2009, pp. 176-177), that is, it is proposed to process signals selected not by all m bandpass filters of the PF, but by randomly selected i pairs of them.

For these purposes, i pairs of filtering channels (block 3 of FIG. 1) are selected at random, for further processing.

The number of selectable channel pairs in each case can be different and is determined by the specified time and probability of detection.

To reduce the performance requirements of analog-to-digital converters of the ADC (block ADC 1 - ADC m Fig. 2) and other digital elements, the signals from the output of the filters are transferred to the intermediate frequency (block IF 1 - IF m, Fig. 2). Next, using amplitude detectors HELL (bl. HELL 1 - HELL m, Fig. 2) select the envelope of the spectrum. Using an analog-to-digital converter, the ADC signals are sampled in time and quantized by levels (block 6, Fig. 1, block ADC 1 - ADC m, Fig. 2).

Then, the degree of interconnection of the selected filtration channels is analyzed by pairwise calculation of the correlation coefficient R s according to the formula 1 (bl. 7, Fig. 1, bl. R s -R sj, Fig. 2) [Ayficher Emmanuel S, Jervis Barry U. Digital processing signals: a practical approach, 2nd edition .: Per. from English - M.: Williams Publishing House, 2004 - 992 p., P. 282, 287]:

Figure 00000003

Where

Figure 00000004

x i (n) is a sequence of signal samples in the ith filtering channel,

x j (n) is the sequence of signal samples in the jth filtering channel,

N is the number of pairs of values.

The calculated value of the correlation coefficient is compared with the decision threshold (bloc 8, Fig. 1, bloc PU 1 - PU j, Fig. 2), determined by the Neumann-Pearson criterion, because with this choice of threshold, a priori probabilities of the absence or presence of a signal are not required (Sosulin Yu.G. “Theoretical Foundations of Radar and Radio Navigation.” - M .: Radio and Communications, 1992, p. 32-33).

When the correlation coefficient exceeds the threshold value (R s > R then ), a decision is made to detect the signal (bloc 9, Fig. 1, bloc "Solver", Fig. 2), the calculated values of the correlation coefficient R s are recorded in the corresponding channel numbers a cell of a preformed matrix (bl. 10, Fig. 1). Determination of the maximum value of a given correlation coefficient R smax determines the fundamental frequency f of the main signal.

Suppose a signal is applied to m filtering channels, the spectrum of which is shown in FIG. 3. A fragment of the matrix with the calculated values of the correlation coefficient by the formula (1) is shown in FIG. four.

To simplify the calculations, we took the normalized value of the spectrum envelope of the signal S (f) from 0 to 1.

From FIG. 4 it can be seen that in column (row) 11 the largest value of the correlation coefficient R s is observed, which corresponds to the maximum value of the spectrum envelope of the signal S (f) (Fig. 3). By performing this sequence of actions, it becomes possible to determine the filtering channel in which the main energy power of the signal will be concentrated.

By varying the width of the filtering channel, it is possible to increase the accuracy of determining the main frequency of operation of unauthorized installed electronic devices.

Thus, even with unknown signal parameters, when implementing this method, NUEUs using ultra-wideband signals will be detected, and the main frequency of operation of NUEUs will be determined.

Claims (1)

  1. A method for detecting an ultrawideband signal, namely, that an ultrawideband signal is supplied to a plurality of m parallel-switched bandpass filters with interconnecting passbands of the same magnitude, the bandwidth of the bandpass filters being much smaller than the signal spectrum width, i pairs of bandpass filters are randomly selected, signals with the outputs of each of which are transferred to an intermediate frequency, amplitude-detected and sampled in time and quantized in level, converting them into digital view, after which the correlation coefficient between the received digital signals is calculated for each pair of bandpass filters, the calculated value of the correlation coefficient is compared with a threshold value, with a correlation coefficient exceeding the threshold value, a decision is made on the presence of a signal, and the calculated values of the correlation coefficient are written into cells, each of which corresponds to the numbers of band-pass filters, a symmetric matrix in which the number of columns and rows is equal to the number m of band-pass filters, compare obtained are values determined cell with the maximum value of the correlation coefficient and determine the basic signal frequency.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2691745C1 (en) * 2018-11-02 2019-06-18 Акционерное общество "Научно-исследовательский институт Приборостроения имени В.В. Тихомирова" Data transmission method

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SU658493A1 (en) * 1975-12-29 1979-04-25 Куйбышевский политехнический институт им.В.В.Куйбышева Arrangement for measuring components of reciprocal spectral density
SU800925A1 (en) * 1978-09-11 1981-01-30 Предприятие П/Я А-7956 Multichannel signal detector
SU894594A1 (en) * 1980-05-08 1981-12-30 Пензенский Политехнический Институт Method and device for spectral analysis of random signals
RU2157050C1 (en) * 1999-07-29 2000-09-27 Гармонов Александр Васильевич Method for measuring frequency and device which implements said method
US20050271120A1 (en) * 2004-06-02 2005-12-08 Lockheed Martin Corporation Detector for time-hopped impulse radio
WO2009075448A1 (en) * 2007-12-10 2009-06-18 Electronics And Telecommunication Research Institute Receiving apparatus and receiving method of impulse-radio uwb wireless system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU658493A1 (en) * 1975-12-29 1979-04-25 Куйбышевский политехнический институт им.В.В.Куйбышева Arrangement for measuring components of reciprocal spectral density
SU800925A1 (en) * 1978-09-11 1981-01-30 Предприятие П/Я А-7956 Multichannel signal detector
SU894594A1 (en) * 1980-05-08 1981-12-30 Пензенский Политехнический Институт Method and device for spectral analysis of random signals
RU2157050C1 (en) * 1999-07-29 2000-09-27 Гармонов Александр Васильевич Method for measuring frequency and device which implements said method
US20050271120A1 (en) * 2004-06-02 2005-12-08 Lockheed Martin Corporation Detector for time-hopped impulse radio
WO2009075448A1 (en) * 2007-12-10 2009-06-18 Electronics And Telecommunication Research Institute Receiving apparatus and receiving method of impulse-radio uwb wireless system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2691745C1 (en) * 2018-11-02 2019-06-18 Акционерное общество "Научно-исследовательский институт Приборостроения имени В.В. Тихомирова" Data transmission method

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