The method of determining the structure of communication systems

 

(57) Abstract:

The invention relates to electrical engineering and can be used for passive monitoring for solving the problem of hidden determine the structure of the communication systems, which is achievable technical result. The method is based on the use of multiple detection stations - direction finding (SOP). Registration of signals from all antennas of all SOPS are produced synchronously. Each SOP coherently accept and register multifrequency signals from multiple transmitters for all databases, educated and support all members of the lattice SOP antennas. The Fourier transform in time restore of the complex spectra of the signals from each antenna and the power spectrum signal of the reference antenna, which comparison with a threshold to choose the frequency at which calculates the complex amplitude of the detected signals. Using the complex amplitude, using a two-dimensional spatial Fourier transform to restore the complex two-dimensional angular spectrum of the detected signals, the module of which is determined by the azimuth and elevation bearings. Convert the signals of the reference antenna of each of the SOP threads pulse signals Xf,,(z) c electron the sensor. In the Central computer associated with all SOPS, using a two-dimensional direction coincides in time and frequency, calculate the location of the transmitters in space, a logical multiplication of streams Xf,,(z) different SOPS form the threads match with address (frequency f, the coordinates and determine the radio network and the communication nodes by matching threads and e-mail addresses of all possible pairs of radiating transmitters. 4 C.p. f-crystals, 9 Il.

The invention relates to electrical engineering and can be used for passive monitoring for solving the problem secretive structure determination (radio networks and nodes) communication systems.

With the advent and improvement of communication systems that use signals with a low probability of intercept, i.e. with increased cryptologically and secrecy (for example, the stepwise change of frequency) problems associated with the determination of their structure in the traditional way - on the semantic content of the communications.

In these conditions, it is necessary to find ways of determining radio networks and nodes, using the statistical regularities of the radio (mutual communication message flows) and other features of the communication systems (e-aorom of the output signals of each element of the antenna array are allocated to digital signals, characterizing the spectra of the received signals, and for each selected frequency band of the reception using the phase signals is a direct calculation of the spatial Fourier series, discrete describing the angular power spectrum at the selected frequency. After recovery of the angular spectrum at all frequencies is determined by the azimuthal bearing any source, emitting signals on any frequency within the current band reception. This way when the direction finding of the maximum possible amplitude and phase information uses only the phase of the signal and determines only the frequency and azimuthal "email address" transmitter that is not enough to define the structure of the controlled system connection.

Known a more efficient way [2], using the definition of frequency and azimuthal email addresses transmitters the maximum possible amplitude-phase information and adopted for the prototype.

According to this method:

1. Coherently accept and register multifrequency signals for all databases, educated and support all members of the grid antenna.

2. Measured time spectra of complex signals from each antenna and break them on often the first antenna with a threshold detected signals of the transmitters, that is, the mark frequency range.

4. Get the complex amplitude of the selected signal by a convolution of the complex-conjugate of the reference spectra and the rest of the antenna.

5. The Fourier transform of the complex amplitude selective frequency restore complex angular spectrum signals of the selected transmitters, using the signal auxiliary antenna as the frequency of the marker transmitter.

6. Obtain estimates of azimuth transmitter on the selected frequencies, using the module of the complex angular spectrum.

In this way actually using one station discovery-finding is constitutive definition of the two most common elements in the structure of communication: e-mail addresses of frequency and azimuthal direction. However, the actual structure of the communication system are not defined.

Thus, the prototype method does not provide a definition of the structure of communication systems.

Using e-mail addresses of frequency and azimuthal direction, you can try to group the detected transmitters and with a low probability to determine the communication nodes, including transmitters, ispolzuya this approach provides a low accuracy of determination of the communication nodes, and does not allow you to use it in practice. As for the issue of opening of radio networks, to solve this information is not sufficient.

The problem solved by the invention is the provision of opportunities for structure determination (radio networks and nodes) communication systems.

The problem is solved by the fact that in the method of determining the structure of communication systems, including coherent reception and check-station detection - direction finding (SOP) multi-frequency signals from several transmitters to all databases, educated and support all members of the lattice SOP antennas, restoring using the Fourier transform of the time-integrated spectra of the signals from each antenna and power spectrum signal of the reference antenna, which comparison with a threshold to choose the frequency at which calculates the complex amplitude of the detected signals according to the invention use multiple SOPS, registration signals from all antennas of all SOPS are produced synchronously, each SOP, using the complex amplitude of each detected signal, using a two-dimensional spatial Fourier transform to restore the complex two-dimensional angular range, the module of which is determined by the azimuth and elevation bearings, convert signinum , elevation ), describing the state of the radiation and pause in the radiation from each transmitter in the Central computer associated with all SOPS, using a two-dimensional direction coincides in time and frequency, calculate the location of the transmitters in space, a logical multiplication of streams Xf,,(z) different SOPS form the threads match with address (frequency f, the coordinates and determine the radio network and the communication nodes by matching threads and e-mail addresses of all possible pairs of radiating transmitters.

Possible special cases of the method, in which:

1. To increase the speed detection transmitters to the stepwise change of frequency (HRS) of the threads allocate groups of threads of different frequency but the same coordinates, logical multiplication of threads dedicated group form streams of matches , and a logical sum - total flows addresses the set of frequencies , coordinates ), a comparison of the total duration of the pulse stream with a threshold to decide about the presence of the transmitter with the WBC if no threshold is exceeded or the possible presence of the communication node when exceeded, and the comparison of each pause flow transmitter with WBC threshold form the pulses flux is CLASS="ptx2">

2. To improve the efficiency of determining radio networks and nodes of the logical multiplication of threads all possible pairs of transmitters with the WBC, as well as flows of all possible pairs typical transmitters form the threads matches Ps(z), describing the magnitude of the statistical relationships in the flow of radiation, and decide that a pair of transmitters is included:

single-frequency (simplex) radio network, if the frequency of radiation transmitters are the same, location are different, and the flow rate of the matches Ps(z) is close to zero;

dual (duplex) radio network, if the frequency and location are different, and the flow rate of the matches Ps(z) is close to zero;

multifrequency radio networks with SICH, if location are different, many frequencies are the same and the flow rate of the matches Ps(z), formed from threads of equivalent radiation is close to zero;

the communication node, if location are the same, the frequencies are different, and the flow rate of the matches Ps(z) differs significantly from zero.

3. To increase the search speed single-frequency radio streams of the matches Ps(z) form of the threads , different POS is due to decide on the presence of the transmitter with SICH, on the existence of statistical relationships in the flow of radiation and streams of equivalent radiation if the inequality

< / BR>
wheresn- the duration of the n-th pulse stream matches in a sample of N fixed tests; and - the distribution parameters pulse duration and average duration of pulses of the stream matches for transmitter with SICH and the communication node, respectively, or for a related (combined in the radio network) and unrelated pairs of transmitters, respectively; c = 1 for the criterion of maximum likelihood, k - threshold decision-making.

Through the use of information about the statistical regularities of the radio (statistical communication flows radiation separate transmitters and mutual statistical relationship in the message flows associated with the radio pairs of transmitters) and these features of communication systems, as a multidimensional email addresses transmitters (frequency, time, azimuth, elevation, coordinates), and also through the use of multi-synchronous method of monitoring, which is implemented by a set of stations of the detection - direction finding, United by a time clock and the Central computer can solve postavlennomu device, which implements the proposed method.

Fig. 2. The spatial separation of the two transmitters RPD 1 and RPD 2, operating on the same frequency.

Fig. 3 and 4. The flow of signals at a fixed frequency f:

Af(z) - after amplitude demodulation filtered at the frequency f of the signals;

Xf(z) - after conversion signals Af(z) into a stream of pulse signals of unit amplitude that describes the flows of the radiation at frequency f without reference to a particular transmitter;

Xf,,(z) - after conversion thread Xf(z) in the streams of signals, different email addresses (frequency f, azimuth , elevation ) and describing the status of radiation and pause in the emission from each transmitter.

Fig. 5. The flows of signals Xf,,(z) and the flow conditions transmitter address (frequency f, the spatial coordinates ).

Fig. 6. Two-dimensional binary image of the distribution of radiation in the coordinates of the frequency f - conditional room p point location transmitters in space".

Fig. 7,and. Flows source and equivalent radiation transmitter with WBC:

- a group of streams with different frequencies (f1...fN) and a matching location ;

- the flow of matches in which eradica with SICH.

Fig. 7,b. Streams of radiation transmitters of communication:

- a group of streams with different frequencies (f1...fN) and a matching location ;

thread coincidence in time of the pulse streams

- the total flux pulse streams

Fig. 8,and. Flows associated with the pair of radio transmitters:

thread separate transmitter;

Ps(z) - stream matches.

Fig. 8,b. Threads not associated with the pair of radio transmitters.

Fig. 9. Example display of inspection results on the electronic map.

These advantages, and features of the present invention will become clear by consideration of the operation of the device that implements the proposed method with reference to the accompanying drawing (Fig. 1).

The device contains M stations detection - direction finding (SOP), each of which includes serially connected, the antenna system 1, the multichannel coherent receiver device 2, a multi-channel APP 3, the block discrete Fourier transform 4 and unit 5. Each SOP through the line radio 6 and unit 7 is connected with the Central computer 8.

Recording of signals on all SOPS are synchronized in time from nocatauth field transmitters coherently received from different antennas, when defining e-mail addresses (two-dimensional bearing, coordinates), and the correlation of streams of binary signals (post-detection correlation signals of the reference antenna, describing the state of the radiation and pause in the radiation from each transmitter) to determine the related pairs of transmitters using one or more of the SOP. In addition to the external signal is highly stable hours, emitted, for example, from a satellite, it is possible to synchronize the time from the internal clock with a high-stability reference source installed on the Central computer 8, or on each SOP. In the latter case, you periodic comparison of hours, for example, using a reference source.

The antenna system 1 contains a reference antenna n = 0 and n = 1...N antennas are combined in a lattice. Multi-channel radio receiving device 2 is made with a common local oscillator and with the bandwidth of each channel, is many times greater than the width of the spectrum of the single signal transmitter. A common local oscillator provides multichannel coherent reception signal, which is a basic condition interferometric (holographic) registration of a complex signal wave fields peredach the AI signals many transmitters. In addition, the device 2 connects a reference antenna n = 0 instead of any of the N antennas of the lattice for periodic calibration of channels external signal source to address their amplitude and phase identical.

The minimum number of channels of the device 2 is equal to two. In this case one of the channels of the device 2 is permanently connected to the reference antenna (n = 0, and the second channel sequentially in time is connected to each of the N antennas of the lattice. When this is implemented more economical from the point of view of needed equipment, but less informative method of successive synthesis of the angular spectrum.

Multichannel ADC 3 is synchronized from the total for all SOP external source.

The block Fourier transform 4 is a multiprocessor and provides parallel processing of multifrequency signals received reference antenna 0 and all N antennas of the array.

The units 5 and 7 together with the communication lines 6 enable the exchange of information between the SOP and the Central computer 8.

A device that implements the method of structure determination (radio networks and nodes) communication systems as follows.

Signals from the pin the Oia two transmitters two spaced stations: SOP 1 and SOP 2.

Each SOP, using a receiving device 2, coherently accept multi-frequency time signals xn(t), where n is the number of antenna element for all databases, reference educated n = 0 and all members of the grid antennas n = 1. . . N, in the band of reception, many times longer than the width of the spectrum of the single signal transmitter.

All SOPS adopted by the radio receiver 2, the signals xn(t) by the ADC 3 synchronously converted into digital signals signals xn(z), where z is the number of the time reference signal, and is recorded in the block Fourier transform 4.

At each station using the Fourier transform 4:

restored complex spectra of the signals from each antenna , where Ft{...} - operator Fourier transform in time and f - number of the frequency reference, that is, the input signals are divided into frequency sub-bands;

choose f - e sub-bands, in which the comparison of the signal power spectrum of the reference antenna with a threshold detected signals of the transmitters, that is, the mark frequency range;

transform on the selected frequency by using the inverse Fourier transform spectra of the reference antenna at the selected frequency in the timing signals , the DG is by programming the amplitude detector (Fig. 3,a and Fig. 4,a);

convert the signals Af(z) by comparing with the threshold U0in the pulse signals of unit amplitude Xf(z) (Fig. 3,b and Fig. 4,b). The threshold is chosen based on the minimization of the probability of missing the signal. Threads pulse signals Xf(z) describe the flow of radiation at frequency f without reference to a specific transmitter. The pulse stream signals Xf(z) corresponds to the presence of radiation at the frequency f, and pause flow - the absence of radiation;

for pre-binding of each pulse of the radiation flux Xf(z) to a specific transmitter determines a two-dimensional bearing radiation (azimuth and elevation) at the frequency f in the interval of existence of the pulse. Why:

get the complex amplitude of the selected signal at the nth antenna by a convolution of the complex-conjugate of the reference spectra and the rest of the antenna at the selected frequency

determine the azimuth and elevation bearings, selected signals by the square of the module of the complex angular spectrum selectively frequency recovered by Fourier transform, using complex amplitudes of the selected signals according to the following formula:

< / BR>
where m = 0,..., K-1 to the current node number, and K is the number of mesh nodes; comprehensive DN of the n-th element; R is the radius of the lattice; wavelength;n= n = 2/N;

selecting the frequency f of the group of pulses with a matching two-dimensional bearings, convert the stream of pulses Xf(z) in streams of pulse signals Xf,,(z) with different email addresses (frequency f, azimuth , elevation ), describing the state of the radiation and pause in the emission from each transmitter.

In Fig. 2 SOP 1 both transmitters are on the same bearing , and for SOP 2 one transmitter is at an angle and the other at an angle , the bearing angle is not shown.

In Fig. 3 for SOP 1 and Fig. 4 for SOP 2 shows the demodulated signals Af(z), the flow pulse signals Xf(z), and the flow pulse signal transmittersf,,().

From the comparison of Fig. 3,b and Fig. 3,it is seen that the SOP 1 stream Xf(z) corresponds to the flow Xf,,(z), because the radiation components of the flow, do not differ in azimuth (bearing) (elevation for simplicity, adopted the same).

From the comparison of Fig. 4,b, 4,and 4 g shows that the on SOP 2 stream Xf(z) is transformed into two streams differing azimuthal direction.

Thus, unlike SOP 1 SOP 2 identified two peredatchika radio modems 5 and 7, line 6 from the output of the block Fourier transform 4 each SOP streams of pulse signals from the Xf,,(z) with the address (f,,) is transferred to the Central computer 8.

In the Central computer 8 performs the following actions:

1. For each frequency f, using a two-dimensional direction (,), obtained at different SOPS in matching the moments of time, calculate the triangulation method of location transmitters in space ;

2. Allot of the threads Xf,,(z) different SOPS flow conditions transmitter address (frequency f, the coordinates ). The pulse stream signal corresponds to the fact simultaneous reception of all SOPS radiation at frequency f, from the point of space , at time z, and pause flow - no radiation.

For signals of traditional communication systems each pulse stream corresponds to a single continuous radiation of the message. Comparing the frequency f, the coordinates and analyzing mutual communication (one person talks and the other at this time, listens to) in the streams of all possible pairs of radiating transmitters, determine single-frequency, dual-frequency and multi-frequency networks. The communication node includes transmitters, which are grouped in space, separated by the hour is OP 1 and SOP 2 two streams Xf,r1(z) and Xf,r2(z) with the same frequency, but different coordinates. This corresponds to a frequency f of the two transmitters spaced. From the analysis of flows Xf,r1(z) and Xf,r2(z) shows that the presence of a pulse in the stream Xf,r1(z) corresponds to the pause flow Xf,r2(z) and Vice versa. Therefore, these two transmitter operating on the same frequency from different points of space are single-frequency radio network.

Unlike traditional communication systems in communication systems with SICH one continuous message is transmitted at different frequencies in successive moments of time. To identify statistical relationships in two radio transmitters with WBC must advance by each transmitter to combine the pulses continuously emitted at different frequencies from one point of space. This corresponds to the formation of equivalent study one subscriber radio networks with SICH.

3. With the aim of preparation for equivalent radiation separate transmitter WBC:

extracted from streams with the same coordinates but different frequencies. This operation allows you to pre-screen radiation, possibly belonging to one who opalewski frequencies, but different coordinates. This operation allows you to pre-screen radiation, possibly belonging to "single" radio network.

To select a group of threads with the same frequency or coordinates a variety of ways. In Fig. 6 shows a two-dimensional binary image of the distribution of radiation in the coordinates of the frequency f is the conditional number p of points the location of the transmitters in space". The point on the image corresponds to the presence of at least one radiation at the frequency f of the p-th point in space. By subjecting this image of the mask in the form of a narrow slit and moving it to the desired dimension, you can select the desired group.

The selection of groups of frequencies and bands of spatial points in addition to the formation of the equivalent radiation of a separate transmitter SICH can significantly reduce the number of possible searches when searching for related pairs of transmitters on the following stages of signal processing. That is due to deliberate search to increase the speed of opening patterns of the communication system.

4. For the formation of the equivalent radiation transmitter with WBC:

4.1. Logical multiplication using multi-input circuits And flows vydelennym schemes OR receive their total flows to address multiple frequencies , the coordinates ). Multi-input circuit And operates on the principle of "minimum 2 matches from n".

Examples of threads shown in Fig. 7. The analysis of Fig. 7,and shows that the impulses of the individual threads do not overlap in time and, as a consequence, the flow of their coincidence in time is close to zero, which is a sign of the transmitter with SICH. In contrast, the flow of coincidences in Fig. 7,b is significantly different from zero and from the total flow , which is a sign of communication.

4.2. To improve the reliability of the total pulse duration of the flow of matches is compared with the threshold k and make a decision about the presence of the transmitter with SICH, if the inequality

< / BR>
wheresn- the duration of the n-th pulse stream matches in a sample of N fixed test;

the distribution parameters for the pulse duration, and average pulse duration of flow matches for transmitter with SICH and the communication node, respectively;

c depends on the quality criterion of selection decisions and for the criterion of maximum likelihood c = 1.

Failure to inequality (1) decide on the availability of the communication node.

Formula (1) obtained using the results Teoriya with SICH a comparison of each pausenthe total flux threshold 0form the pulse stream is equivalent to the radiation transmitter with SICH grouping of pulses of the stream , pause between which satisfy the conditionn0(Fig. 7,a).

5. Logical multiplication using two-input circuits And flows of equivalent radiation of all possible pairs of transmitters with the WBC, as well as flows of all possible pairs typical transmitters form the threads matches Ps(z), describing the magnitude of the statistical relationships in the flow of radiation (Fig. 8) and decide that a pair of transmitters is included:

single-frequency (simplex) radio network, if the frequency of radiation transmitters are the same, location are different, and the streams of radiation are statistically associated, that is, the flow rate of the matches Ps(z) is close to zero or, more informative, the total pulse duration of flow Ps(z) satisfies the inequality , wheresn- the duration of the n-th pulse stream matches Ps(z) in a sample of N fixed tests, a threshold decision; - the distribution parameters pulse duration and average pulse duration of flow matched related (combined in radiochastotnoi (duplex) radio network, if the frequency of the radiation and the location of the transmitters differ, and ;

multifrequency radio networks with SICH, if the location of the transmitters SICH different, multiple frequency radiations are the same and flows equivalent of two radiation transmitters are statistically associated, that is ;

communication node, if the location of the transmitters are the same, the frequency of radiation differ, and streams statistically unrelated, i.e .

7. To improve the informative display on the electronic map of the spatial structure of the communication system in the form of points corresponding to the locations of the transmitters, and lines corresponding to the identified mutual relations (Fig. 9).

Thus, performing these actions on signals in spatially separated stations detection - finding and in the Central computer determines the radio network and the communication nodes, that is, reveal the structure of the communication system according to the degree of match threads radiation and e-mail addresses (frequency, location) transmitters.

Improving the accuracy and speed of identifying radio networks and communication is achieved by using:

statistical regularities of the radio (statistical the deposits associated with the radio pairs of transmitters);

characteristics of communication systems, such as multidimensional email addresses transmitters (frequency, time, azimuth, elevation, coordinates);

multi-synchronous method of monitoring, which is implemented by a set of stations of the detection - direction finding, United by a time clock and a Central computer.

Sources of information

1. US patent 4626859, CL G 01 S 5/04, 1986

2. RU, patent, 2096797, CL G 01 S 3/14, 1996

3. Levin, B. R. Theoretical foundations of statistical radio engineering. In three books. The second book. Ed. 2nd, Rev. and expanded. - M.: Owls. Radio, 1975. - 392 S.

1. The method of determining the structure of communication systems, including coherent reception and check-station detection - direction finding (SOP) multi-frequency signals from several transmitters to all databases, educated and support all members of the lattice SOP antennas, restoring using the Fourier transform of the time-integrated spectra of the signals from each antenna and power spectrum signal of the reference antenna, which comparison with a threshold to choose the frequency at which calculates the complex amplitude of the detected signals, characterized in that use multiple SOPS, study each detected signal, using two-dimensional spatial Fourier transform to restore the complex two-dimensional angular spectrum of the detected signals, the module of which is determined by the azimuth and elevation bearings, convert the signals of the reference antenna of each of the SOP threads pulse signals Xf,,(z) with email addresses (frequency f, azimuth, elevation ), after describing the state of the radiation and pause in the radiation from each transmitter in the Central computer associated with all SOPS, using a two-dimensional direction coincides in time and frequency, calculate the location of the transmitters in space triangulation method, a logical multiplication of streams Xf,,(z) different SOPS form the threads match with address (frequency f, coordinates) analyze mutual communication transmitters and determine the radio network and the communication nodes by matching threads and e-mail addresses of all possible pairs of radiating transmitters.

2. The method according to p. 1, characterized in that Molotkov distinguish groups of threads of different frequency but the same coordinates, logical multiplication of threads dedicated group form streams of matches , and a logical sum - total flows from the Adra is tion of the presence of the transmitter to the stepwise change of frequency (HRS) when not exceeding the threshold or on the possible presence of the communication node when exceeded, and the comparison of each pause flow transmitter with WBC threshold form the pulse stream is equivalent to the radiation , describing the state of the transmission message and pause the transmission of the transmitter with SICH.

3. The method according to p. 2, characterized in that the logical multiplication of threads all possible pairs of transmitters with the WBC, as well as flows of all possible pairs of transmitters that are not classified as SICH, forming streams of matches Ps(Z), describing the amount of static links in threads radiation, and decide that a pair of transmitters is included: single-frequency simplex radio network, if the frequency of radiation transmitters are the same, location are different, and the flow rate of the matches Ps(Z) is close to zero; two-frequency duplex radio network, if the frequency and location are different, and the flow rate of the matches Ps(Z) is close to zero; multi-frequency radio networks with SICH, if location are different, many frequencies are the same and the flow rate of the matches Ps(Z), formed from the stream of equivalent radiation is close to zero; the communication node, if location are the same, the frequencies are different, and the flow rate of the matches Ps(Z) essential potokov , different coordinates, but the same frequency.

5. The method according to p. 2 or 3, characterized in that the decision about the presence of the transmitter with SICH, the existence of statistical relationships in the flow of radiation and streams of equivalent radiation if the inequality

< / BR>
wheresn- the duration of the n - th pulse stream matches Ps(Z), in a sample of N fixed test;

the distribution parameters of pulse duration;

the average durations of the pulses of the stream matches for transmitter with SICH and the communication node, respectively, or for related and combined in the radio network and unrelated pairs of transmitters, respectively;

C = 1 for the criterion of maximum likelihood.

 

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