RU2538195C1 - Method of recognising pulse interference source signals (versions) and system therefor (versions) - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: in a method based on receiving direct radiation of a source and reflection thereof from an object, measuring the time shift of said radio-frequency radiations based on the position of the maximum of a cross-correlation function, the reflecting object used is an active or passive relay; the method comprises receiving pulse sequences - the sequence reradiated by the relay and received in viewed direction; eliminating the time shift of the sequences; optionally determining the correlation value of pulses of the sequences; pulses received from the viewed direction, which correspond to a defined criterion of determining interference are considered pulses of a pulse jammer. Said result according to the second version is achieved due to that, in a method based on receiving radiation of a source with known coordinates and reflection thereof from an object with known coordinates, measuring the time shift between said radiations, the reflecting object used is an active or passive relay; the method comprises receiving pulse sequences - radiated by a repeater jammer from the viewed direction and reradiated by the relay; the latter is used to calculate the time of radiating pulses of the repeater jammer and said pulses are recognised in the first sequence.

EFFECT: recognising interference pulses, including repeater jamming pulses in a stream of received signals from radio-frequency radiation sources.

8 cl, 5 dwg

Description

The claimed technical solutions relate to the field of radar and can be used in radar stations (radar) to protect against pulsed, including response, interference.

Big problems for the operation of the radar create impulse noise and, above all, response noise (Protection from radio interference. Edited by MV Maksimov. - M .: Sov. Radio, 1976, p. 60). As a result of their actions, false detection of targets occurs, since the received response interference signals do not differ in structure from signals reflected from real targets. The interference is especially effective when the jammer re-emits an amplified copy of the sounding signal and the level of interference does not depend on the level of the sounding signal. With a sufficiently large response interference power, it is detected not only in the main beam, but also along the side lobes of the antenna radiation pattern (BOTTOM), as a result of which a large number of false signals (marks) are chaotic or stationary, in the simplest case, or moving with the installed the director of the interference speed in the case of synchronous response interference. In all cases, the interference pulses are perceived as reflected from the targets, therefore, they capture and tie the track (SZ Kuzmin. Fundamentals of designing digital radar information processing systems. Page 109) with their subsequent reset in the event of non-synchronous interference or false tracking in case of synchronous interference with varying delay. As a result, the response interference leads to an overload of the signal processing devices and tracking of the target traces.

Particularly difficult is the task of distinguishing targets masked by false signals under the action of response interference in the main beam of the DND.

Known methods for suppressing interference in the main beam of the BOTTOM of a single-position radar, which include the use of AGC, restrictions or compensation (Theoretical Foundations of Radar. Edited by Y.D. Shirman. - M .: Sov. Radio, 1978, pp. 298-302, 346- 347).

A disadvantage of the known interference suppression methods is that in the case of response interference with a high power level, they do not provide interference suppression, since it does not differ in structure from the signals of real targets and can significantly exceed the level of these signals in level.

Thus, the known methods do not allow suppressing the response interference. But it is possible to exclude the overload of the processing and tracking devices of target paths without suppressing the interference if its impulses are recognized.

Known for the closest to the features used in the proposed method, the method of radar determination of the coordinates of the source of radio emission and the radar station for its implementation (patent RU 2217773 C2), based on the reception of direct radiation of the source and its radio emission reflected from the object, measured by the position of the maximum mutual correlation function of radio emissions the magnitude of the time shift Δt of these radio emissions, measuring the elevation angle and azimuth of the radiation source, as well as the distance to the object reflecting the radio radiation and calculate the range to the radiation source.

Known closest to the proposed complex - radar station (radar) (patent RU 2217773 C2) (figure 1). Radar 1 contains active 3 and passive 4 detection channels, passive channel 4 includes a series-connected antenna 6 and a receiver 12, as well as a coordinate calculation unit 16, comprising a series-connected device for measuring the shift of the received signals in time 13 and a coordinate calculation device 14, the antenna coordinate output 6 is connected to the second input of the coordinate computing device 14, and the output of the receiver 12 is connected to the first input of the time shift signal measuring device 13, the active detection channel 3 contains the last The antenna 5, antenna switch 7, receiver 9 and range calculator 11 are connected together, the second input of antenna switch 7 is connected to the output of transmitter 8, the output of range calculator 11 is connected to the fifth input of coordinate calculator 14, and the coordinate output of antenna 5 is connected to fourth the input of the coordinate calculating device 14, the outputs of the synchronizer 10 are connected to the corresponding synchro inputs of the transmitter 8, the range calculating device 11 and the coordinate calculating device 14.

The complex works as follows.

At the first stage, using the passive channel 4 of the radar 1, the angular coordinates of the source of radio emissions are detected and determined 15. At the second stage, the channel 3 of the radar 1 in the passive mode detects and receives reflections from object 2, determines its angular coordinates and calculates the relative delay of the signals in the channels to the maximum correlation function. At the third stage, the channel 3 of the radar 1 in the active mode determines the range to the object 2 and in the coordinate calculation device 14 determines the range and angular coordinates of the source of radio emissions 15.

A disadvantage of the known method and device is that they do not allow to recognize interference pulses, including response pulse pulses in the stream of received signals.

Thus, the task (technical result) is the recognition of interference pulses, including response interference pulses in the stream of received signals from radio sources.

The task (technical result) according to the first embodiment is solved by the fact that in a method based on the reception of direct radiation of a source and its reflection from an object that is correlated with direct radiation, measuring, according to the position of the maximum of the mutual correlation function, the time shift of these radio emissions, according to the invention in an active or passive repeater is used as a reflecting object, pulse sequences are received - the sequence re-radiated by the repeater and received from osmosis of the direction being monitored, the time shift of the sequences is eliminated, if necessary, the correlation value of the sequence pulses is determined, the pulses received from the direction being examined, corresponding to the established criterion for determining interference, are considered to be pulses of the pulse interference director.

The task (technical result) in the first embodiment is also solved by the fact that as a criterion for the impulses of the impulse noise producer, the coincidence in time of the impulses of the sequences is used.

The task (technical result) in the first embodiment is also solved by the fact that, as a criterion for the impulses of the impulse noise producer, the level of correlation of the impulses of sequences exceeding the average level is used.

The task (technical result) in the first embodiment is also solved by the fact that, as a criterion for the impulses of the impulse noise producer, the correlation function exceeds the threshold level, which is determined by the admissible probability of recording false interference as real.

The task (technical result) in the first embodiment is also solved by the fact that the threshold level is used as a criterion for the impulses of the impulse noise producer, which is automatically changed from the maximum value to the value at which the loading of processing and tracking devices does not exceed the permissible one.

The problem (technical result) in the second embodiment is solved by the fact that in the method based on the direct radiation of a source with known coordinates and its reflection from an object with known coordinates, measuring the time shift between these radiations, according to the invention, an active object is used as a reflecting object or passive repeater, receive pulse sequences - radiated by the response interference director (POP) and reemitted by the repeater, the moments are calculated from the last radiation of POP pulses and recognize them in the first sequence.

The task (technical result) is achieved in that the complex for implementing the method according to the first embodiment includes a radar containing active and passive detection channels, the passive channel includes a series-connected antenna and receiver, as well as a coordinate calculation unit, the active channel includes a series-connected antenna, antenna switch, receiver, transmitter and synchronizer, the output of the transmitter is connected to the second input of the antenna switch, the output of the synchronizer is connected to the sync inputs of the transmitter transmitter and receiver, according to the invention, a response interference and target recognition unit (RPIC) and a passive or active repeater are introduced, and a correlation coefficient calculation unit (VCC), a threshold device (PU) and a controlled correlator delay line (LZK) are introduced into the coordinate calculation unit, the output of the receiver of the passive channel is connected to the first input of the IAC, the second output of the IAC is connected to the input of the PU, the output of the receiver of the active channel is connected to the first input of the IAC, the first output of the IAC is connected to the second input of the IAC, the second output of the IAC is connected to the first input RPiTs house unit PU and the output is connected to the second input RPiTs, WCC first output connected to the second input LZK, the repeater located in the line of radar sight.

The task (technical result) is achieved by the fact that the complex for implementing the method according to the second embodiment, which is a radar that contains active and passive detection channels, the passive channel includes a series-connected antenna and receiver, as well as a coordinate calculation unit containing a series-connected calculation device the received signal shift in time (BCB) and the coordinate calculation device (VK) of the response interference director (POP), the output of the receiver is connected to the input of the unit Coordinates, the active detection channel includes a series-connected antenna, antenna switch and receiver, as well as a transmitter, the output of which is connected to the second input of the antenna switch, according to the invention, an impulse emission moment calculation unit (IMWM), an RPiC unit and a unit are introduced into the active radar channel a single time sensor (DEV), as well as a passive or active repeater, the first VMIZ input is connected to the output of the active channel receiver, the second VMIZ input is connected to the second BCB output, the VMIZ output is connected to the input ohm RPiTs, DEV outputs respectively connected to the clock terminal of the transmitter, receiver, VMIZ blocks RPiTs, devices and VC ENE, the repeater located in the line of radar sight.

The essence of the method according to the first embodiment is that a single-position radar containing active and passive channels emits a pulse, POP in response to a received radar pulse emits a response noise in the form of a sequence of pulses identical in structure to the radar pulse. In this case, the active radar channel, which is in the receiving mode, receives pulses reflected from the target and a direct sequence of response interference. The repeater re-radiates the interference received by the passive channel.

If the correlation functions for each pulse of the sequences are calculated after eliminating the time shift of the direct sequence by the path difference Δt of the pulses from the POP and through the repeater, only interference pulses remain correlated, since the time of the path difference for the interference and target pulses will be different (Fig. 5). The magnitude of the shift in time, as in the prototype, is determined by the maximum of the total correlation function.

имеет максимальное значение, так как эти импульсы совпадают во времени, $${\displaystyle \underset{0}{\overset{\tau }{\int }}{П}_i\times {Ц}_j}$$

и $${\displaystyle \underset{0}{\overset{\tau }{\int }}{П}_j\times {Ц}_i}$$

равны нулю, так как импульсы от цели и помехи приходят в разное время. При этом Φ_кΔt имеет максимальное значение.At Δt, the integral $${\displaystyle \underset{0}{\overset{\tau }{\int }}{P}_i\times P_j}$$

has a maximum value, since these pulses coincide in time, $${\displaystyle \underset{0}{\overset{\tau }{\int }}{P}_i\times {\mathrm{Ts}}_j}$$

and $${\displaystyle \underset{0}{\overset{\tau }{\int }}{P}_j\times {\mathrm{Ts}}_i}$$

are equal to zero, since the impulses from the target and interference come at different times. Moreover, Φ to _Δt has a maximum value.

P _i and C _i are the impulses of the response interference and the target in the sequence from the direction being examined, where i = 1 ... n, n is the number of impulses of the interference and targets.

P _j and C _j are the interference pulses and targets, in the sequence reflected by the repeater, where j = 1 ... k is the number of pulses reflected by the repeater. Pulses received from the inspected direction, corresponding to the established criteria for determining interference, are considered interference. The following criteria are considered to be the interference criteria of the response interference emitted by the director:

1) coincidence in time of pulse sequences;

2) excess of the average level of correlation of pulse sequences;

3) exceeding the threshold level, which is determined by the admissible probability of recording false interference as real.

In this case, the threshold level is set as follows.

In the absence of response interference, the mutual correlation between the noise of the active and passive channels is calculated with a constant integration equal to the radar pulse duration. Since the integration time is limited, the calculated correlation function will not be zero, but will fluctuate with the dispersion σ. The threshold level is chosen so that its excess by the noise correlation function occurs no more than m times in the selected time T (see Fig. 5). In this case, the probability of skipping (unrecognizing) the interference is determined by the ratio of the variance and the maximum level of the interference correlation function. Gaps in the correlation of interference pulses mean tying up false paths;

4) exceeding the threshold level, which is automatically changed from the maximum value to a value at which the loading of processing and tracking devices does not exceed the permissible one.

Thus, they are able to recognize the signals emitted by the director of impulse and, including response, interference, which achieves the solution of the problem and the technical result.

The essence of the method according to the second embodiment is that direct radiation of a source with known coordinates and re-emitted by an active or passive repeater, the coordinates of which are known, is measured, measuring the time shift between these radiations, the moment of emission of the source pulses is determined from the latter and recognized in direct radiation . The problem is solved as follows:

1) the range from the radar to the emitter (POP) is known and equal to d;

2) determine the distance r _C from POP to the repeater from the triangle of the ACV (figure 3) by the formula

; α_Р - угол между направлениями на ретранслятор и на ПОП, определяется по формулеwhere C is the speed of light; $$\Delta T_A=\frac{d}{c}$$

; α _P - the angle between the directions to the repeater and to POP, is determined by the formula

α _P = arcosCosβ _P × Cosε _P ,

where β _P and ε _P are the azimuth and elevator angle of the repeater relative to the direction to POP;

r _A is the known distance from the radar to the repeater;

3) from the known at a single time the moment of reception t _{pr of the} reflected pulse from the repeater, the known distance from the radar to the repeater r _A and the calculated value of r _C determine the moment of emission of interference pulses t _And by the formula

where (τ _A + τ _C ) is the total propagation time of the pulse from the POP to the repeater and from it to the radar;

;

;

By the known distance d and the moment of radiation of the pulse POP t _And recognize the impulse, including the response, interference.

Thus, the task is solved and a technical result is achieved in the method according to the second embodiment.

The invention is illustrated by drawings:

figure 1 - complex that implements the prototype method;

figure 2 - the claimed complex that implements the claimed method according to the first embodiment;

figure 3 is a diagram illustrating the operation of the inventions;

figure 4 - the claimed complex that implements the proposed method according to the second embodiment;

5 is a diagram explaining the operation of the method according to the first embodiment.

The claimed complex that implements the claimed method for recognizing signals of a pulsed radio source according to the first embodiment (Fig. 2) contains a radar 1, which includes active 3 and passive 4 detection channels, passive channel 4 includes a series-connected antenna 6 and receiver 10, as well as a calculation unit coordinate 16, comprising a correlation coefficient calculation unit 13, a controlled correlator 12 delay line, a response interference and target recognition unit 18, and a threshold device 17, an active or passive repeater, output the passive channel receiver 10 is connected to the input of the HCC 13, the active channel 3 includes a series connected antenna 5, antenna switch 7, receiver 9, transmitter 8 and synchronizer 11, the output of transmitter 8 is connected to the second input of antenna switch 7, the output of synchronizer 11 is connected to the transmitter sync inputs 8 and receiver 9, the output of the receiver 9 of the active channel is connected to the first input of the LZK 12, the first output of the LZK 12 is connected to the second input of the VKK 13 block, the second output of which is connected to the input of the PU 17, the second output of the LZK 13 is connected to the first input unit RPiC 18, and the output of the control unit 17 is connected to the second input of the RPiC 18, the first output of the VKK 13 is connected to the second input of the LZK, the repeater is located in the line of sight of the radar.

Consider in more detail the feasibility of the method according to the first embodiment (figure 2) on a specific example. The radar 1 emits pulses in the direction of POP 15, and it emits a response interference, which is reflected from the repeater 2 and is received by the antenna 6 of the passive channel 4, and the antenna 5 of the active channel 3 receives the direct radiation of the POP 15. Pulses received by the active channel 3 and the passive channel 4, received at the input of the coordinate calculation unit 16. In which the pulses received by the active channel 3 are fed to the input of the controlled LZK 12, the pulses received by the passive channel 4 are fed to the first input of the VCC unit 13, and the signal from the first you controlled LZK 12 and with a certain value of the delay Δt is the maximum correlation function of each pulse. The pulses from the output of the active channel 3, representing direct radiation of POP 15, pass through the same controlled LZK 12, and if they are correlated with the pulses in the passive channel 4, then they are considered interference. This allows you to recognize pulsed, including response, interference from pulses reflected from the target.

Thus, the claimed technical result is achieved (the task is solved).

The claimed complex according to the second embodiment, which implements the claimed method for recognizing pulsed, including response, interference (Fig. 4), contains radar 1 and relay 2, radar 1 includes active 3 and passive 4 detection channels, passive channel 4 includes a series-connected antenna 6 and a receiver 12, as well as a coordinate calculation unit 16, including a device for measuring the shift of received signals in time 13 and a coordinate calculation device 14, an active channel 3, comprising an antenna 5 connected in series , antenna switch 7, receiver 9 and transmitter 8, a single time sensor unit 19, a radiation moment calculation unit 17 and an interference and target recognition unit 18 are introduced, the output of the receiver 9 is connected to the first input of the VMIZ 17, to the second input of the BCB 13 and the second input of the RPiC block 18, the output of the VMIZ block 17 is connected to the first input of the RPiC 18 block, the output of the transmitter 8 is connected to the second input of the antenna switch 7, the coordinate outputs of the antennas 5 and 6 of the active and passive channels are connected to the second and third inputs of the VK 14 device but, the first output of the BCB 13 device is connected to the second input of the VMIZ 17, and its second output is connected to the first input of the VK 14 device, the output of the VK 14 device is connected to the third input of the VMIZ 17, the output of the DEV 19 unit is connected to the clock inputs of the transmitter 8, receiver 9, VMIZ blocks 17 and RPiC 18, VK 14 and BCB 13 devices, the repeater is located in the line of sight of radar 1.

Consider in more detail the feasibility of the method and complex according to the second embodiment (figure 4) for a specific example. Using radar 1, pulses are emitted in the direction of POP 15, and it emits a response interference, which is re-emitted by repeater 2 and received by antenna 6 of passive channel 4. Using antenna 5 of active channel 3, direct radiation of POP 15 is received. Signals received by active channel 3, arrive at the first input of the VMIZ 17, at the second input of the BCB 13 device and to the second input of the RPiC block, the signals received from the relay 2 by the passive channel 4 are fed to the first input of the BCB 13 and then to the input of the VK 14 device using the VMIZ 17 determine the moment radiated I POP 15, and in block 18 RPiTs produce reciprocal recognition of interference.

Thus, the task is solved and the claimed technical result is achieved in the method and device according to the second embodiment.

Claims (8)

1. A method of recognizing signals of a pulsed noise source, based on the reception of direct radiation of the source and its reflection from the object, which is correlated with direct radiation, measuring the magnitude of the time shift of these radio emissions from the maximum position of the mutual correlation function, characterized in that an active object is used as a reflecting object or passive repeater, receive pulse sequences - the sequence re-radiated by the repeater and received from the inspected direction, eliminate dissolved time shift sequences determined correlation value sequences of pulses, if necessary, the pulses received from the examined directions corresponding to the specified criteria is considered pulses director impulse interference. 2. The method according to claim 1, characterized in that as the criterion for the pulses of the director of the pulsed noise using the coincidence in time of the pulses of the sequences. 3. The method according to claim 1, characterized in that as a criterion for the pulses of the director of impulse noise using the level of correlation of pulses of sequences exceeding the average level. 4. The method according to claim 1, characterized in that, as a criterion for the impulses of the impulse noise producer, the correlation function exceeds the threshold level, which is determined by the admissible probability of detecting false interference as real. 5. The method according to claim 1, characterized in that the threshold level is used as a criterion for the impulses of the impulse noise producer, which is automatically changed from the maximum value to the value at which the loading of processing and tracking devices does not exceed the permissible level. 6. The complex for implementing the method according to claim 1, comprising a radar station, which includes an active and passive detection channels, a passive channel includes a serially connected antenna and a receiver, as well as a coordinate calculation unit, an active channel includes a serially connected antenna, an antenna switch , the receiver, the transmitter and the synchronizer, the output of the transmitter is connected to the second input of the antenna switch, the output of the synchronizer is connected to the synchro inputs of the transmitter and receiver, characterized in that a reciprocal interference and target recognition unit (RPiC) and a passive or active repeater are given, and a correlation coefficient calculation unit (VCC), a threshold device (PU) and a controlled correlator delay line (LPC) are entered into the coordinate calculation unit, the output of the passive channel receiver is connected to the first input of the IAC, the second output of the IAC is connected to the input of the control unit, the output of the receiver of the active channel is connected to the first input of the IAC, the first output of the IAC is connected to the second input of the IAC, the second output of the IAC is connected to the first input of the RPiC unit, and the output of the PU is connected to the sec the first input of the RPiC, the first output of the HCC is connected to the second input of the LZK, the repeater is located in the line of sight of the radar. 7. A method for recognizing signals of a pulsed noise source based on the reception of direct radiation from a source with known coordinates and its reflection from an object with known coordinates, measuring the time shift between these radiations, characterized in that an active or passive repeater is used as a reflecting object, pulsed sequences - radiated by the response interference director (POP) and re-emitted by the repeater, the moments of the radiation of POP pulses and know them in the first sequence. 8. The complex for implementing the method according to claim 7, containing a radar station (RLS), which includes active and passive detection channels, the passive channel includes a series-connected antenna and receiver, as well as a coordinate calculation unit containing a series-connected device for calculating the shift of the received signals in time (BCB) and coordinate calculation device (VC), the output of the receiver is connected to the input of the coordinate calculation unit, the active detection channel includes a series-connected antenna, antennas the first switch and receiver, as well as the transmitter, the output of which is connected to the second input of the antenna switch, characterized in that the pulse emitting moment calculation unit (IMIZ), the interference and target recognition unit (RPiZ), the unit of the single-time sensor ( DEV) and a passive or active repeater, the first VMIZ input is connected to the output of the active channel receiver, the second VMIZ input is connected to the second BCB output, the VMIZ output is connected to the RC&C input, the DEV outputs are connected to the sync inputs of the transmitter, receiver, unit in VMIZ, RPiTs, device VC and ENE, a repeater in the line of radar visibility.

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