A two-dimensional smart noise jamming method based on centralized MIMO radar

Abstract

The application discloses a two-dimensional smart noise jamming method based on centralized MIMO radar and belongs to the technical field of radar communication. First, an interference machine is used to perform down-conversion processing on radar transmitting signals intercepted by a digital radio frequency memory, and then, through intermittent sampling, each pulse of the signal transmitted by an enemy is periodically sampled to form multiple slices, smart noise jamming modulation is performed in the distance dimension and the speed dimension respectively, and finally, the modulated signal is subjected to up-conversion processing, so as to form a two-dimensional smart noise jamming signal of the retransmission type. After the MIMO radar receives the jamming signal, the result obtained through a conventional signal processing method is seriously affected by the jamming signal generated in the application. The application successfully generates dense false targets by exerting smart noise jamming on the radar signal of the enemy in the distance dimension and the speed dimension, so as to interfere with the detection of a real target by the MIMO radar.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of radar communication, and particularly relates to a two-dimensional smart noise jamming method based on centralized MIMO radar. BACKGROUND

[0002] Multiple Input Multiple Output (MIMO) radar has become an important development direction of modern radar systems due to its high resolution, multi-target detection capability and spatial degree of freedom. However, with the wide application of MIMO radar technology in military and civilian fields, it has become a key target of electronic countermeasures. The design of jamming signals for MIMO radar is an important countermeasure in electronic warfare, aiming to weaken or destroy the detection performance of the radar through specially designed jamming signals, and achieve the effect of misleading or masking targets.

[0003] Deception jamming is a key method of designing jamming signals for radar echo characteristics, common means including time delay deception, frequency shift deception and Doppler deception. For MIMO radar, signals similar to its transmit waveform but containing bias information can be generated to mislead the radar's range and speed estimation. Due to the complex processing capability of MIMO radar, a single type of jamming often fails to work. Joint use of noise jamming, deception jamming and spatial jamming and other strategies can effectively improve the success rate of jamming.

[0004] MIMO radar jamming signal design needs to combine radar system characteristics and countermeasures, and comprehensively consider the strength, directivity, spectral characteristics and flexibility of the jamming signal to take the initiative in electronic countermeasures. This is not only a technical challenge, but also an important research direction of modern electronic warfare development. SUMMARY

[0005] The purpose of the present application is to provide a two-dimensional smart noise jamming method based on centralized MIMO radar, which can obtain greater accumulation gain at the receiving end of the MIMO radar using smart jamming signals, and has higher jamming power utilization rate; through the two-dimensional smart noise jamming of the present application, interference can be generated in the range dimension and the speed dimension at the same time, and the target is better protected.

[0006] The technical solution of the present application is as follows: a two-dimensional smart noise jamming method based on centralized MIMO radar, comprising the following steps:

[0007] Step 1, the jammer performs down-conversion processing on the radar transmit signal intercepted by the digital radio frequency memory, and periodically samples each pulse of the signal transmitted by the enemy through intermittent sampling to form multiple slices;

[0008] Step 2, respectively, in the distance dimension, the velocity dimension is smart noise interference modulation;

[0009] Step 3, the modulated signal is up-converted to form a two-dimensional smart noise jamming signal.

[0010] Further, under the action of the interference signal, the centralized MIMO radar obtains the results according to the signal processing flow, including the distance dimension matching filter, the velocity dimension FFT operation; due to the smart noise design of the interference signal in the distance dimension and the velocity dimension, dense false targets will appear in the detection results of the radar, and the echo signals of the real targets will be covered or interfered.

[0011] A computer device comprises a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the program.

[0012] A computer readable storage medium, which stores a computer program, wherein the program is executed by a processor to implement the steps of the above method.

[0013] A computer program product comprising a computer program, wherein the computer program is executed by a processor to implement the steps of the above method.

[0014] Compared with the prior art, the two-dimensional smart noise interference signal designed in the application can produce dense false targets in the distance dimension and the velocity dimension after MIMO radar signal processing, which cannot be achieved by traditional interference signals; and by adjusting the bandwidth of the two-dimensional noise signal, the distribution of interference energy can be flexibly controlled, the interference range can be controlled, and the purpose of protecting multiple targets can be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0016] Figure 1 It is a flowchart of the two-dimensional smart noise interference method based on centralized MIMO radar.

[0017] Figure 2 It is a composition principle block diagram of two-dimensional smart noise jammer.

[0018] Figure 3 It is a MIMO radar interference scene diagram.

[0019] Figure 4MTD plot with two-dimensional wily noise jamming.

[0020] Figure 5 Range dimension result plot without jamming.

[0021] Figure 6 Range dimension result plot with jamming.

[0022] Figure 7 Velocity dimension result plot without jamming.

[0023] Figure 8 Velocity dimension result plot with jamming.

[0024] Figure 9 MTD plot with two-dimensional wily noise jamming under different noise bandwidths.

[0025] Figure 10 Multi-target MTD plot without two-dimensional wily noise jamming.

[0026] Figure 11 Multi-target MTD plot with two-dimensional wily noise jamming. DETAILED DESCRIPTION

[0027] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings in the embodiments of the present application to describe the technical solutions in the embodiments of the present application in detail and completely. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Generally, the components of the embodiments of the present application described and shown in the accompanying drawings can be arranged and designed using different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not only to limit the scope of the claimed present application, but only to represent selected embodiments of the present application.

[0028] The application discloses a two-dimensional smart noise jamming method based on centralized MIMO radar and belongs to the technical field of radar communication.

[0029] In combination Figure 1 with the above, the embodiment of the application provides a two-dimensional smart noise jamming method based on centralized MIMO radar, and the jammer based on a jammer receiver and a digital radio frequency memory performs the following processing on a radar signal:

[0030] Step J1, the jammer performs down-conversion processing on a radar transmission signal intercepted by a digital radio frequency memory (DRFM), periodically samples each pulse of the signal transmitted by an enemy party through intermittent sampling to form multiple slices;

[0031] Step J2, smart noise jamming modulation is performed in the range dimension and the velocity dimension respectively;

[0032] Step J3, the modulated signal is subjected to up-conversion processing, thereby forming a two-dimensional smart noise jamming signal in a retransmission mode;

[0033] Step J4, under the action of the jamming signal, the result obtained by the centralized MIMO radar according to a conventional signal processing procedure includes range dimension matching filtering, velocity dimension FFT and the like. However, due to the smart noise design of the jamming signal in the range dimension and the velocity dimension, dense false targets appear in the detection result of the radar, and the echo signal of a real target is covered or jammed.

[0034] In step J1, if the MIMO radar has M transmission elements, each channel transmits mutually orthogonal signals, the composition principle of the jammer is as shown in Figure 2 The MIMO radar transmission signal intercepted by the jammer can be expressed as:

[0035]

[0036] where t r represents fast time, f c is carrier frequency, and s i(tr) represents the transmitted signal of the i

[0037] When the jammer intercepts the MIMO transmitted signal, it is first down-converted to obtain the baseband intercepted signal:

[0038]

[0039] where t a represents slow time, represents convolution operation, τ(t a ) = (R0-vt a ) / c represents the one-way time delay of the MIMO radar to the jammer, R0 and v represent the initial slant range and radial velocity of the jammer relative to the MIMO radar respectively, and c is the speed of light.

[0040] In step J2, the noise signal in the range dimension and the velocity dimension is a noise frequency modulation signal:

[0041]

[0042] where the modulated noise signal u(t) is a generalized stationary random signal with zero mean, U j is the amplitude of the interference signal, and the initial phase is uniformly distributed on [0, 2π] and is independent of u(t), ω j is the center frequency of the interference, and K FM is the slope of the frequency modulation, representing the frequency change caused by the unit intensity of the modulation signal.

[0043] The jammer multiplies the intercepted signal with the locally pre-generated noise template n(t r , t a ) to obtain the modulated interference signal:

[0044] m(t r , t a ) = n(t r , t a ) s in (t r , t a )

[0045] where the noise template is non-correlated in the fast time dimension and the slow time dimension. The single side bandwidths of the corresponding dimensions are B nr and B na respectively. By adjusting the noise bandwidths of the corresponding dimensions, the distribution of the dense false targets in the range dimension and the velocity dimension can be flexibly controlled.

[0046] In step J3, the jammer up-converts the modulated signal to form a repeatered two-dimensional smart noise jamming signal:

[0047]

[0048] where τ j is the fixed repeatered time delay of the jammer. jr (t r ) and s ja (t a ) represent the fast-time and slow-time echo components at the jammer, respectively.

[0049] The baseband jamming signal received by the MIMO radar can be expressed as:

[0050]

[0051] where

[0052]

[0053] τ0= R0 / c is the initial one-way time delay, f d = 2v / λ is the Doppler frequency, and λ is the wavelength of the transmitted signal.

[0054] In step J4, the MIMO radar performs matched filtering on each fast-time sampling unit of the jamming signal, and at this time, the range dimension jamming model can be expressed as:

[0055] r(t r ) = n(t r )s jr (t r )

[0056] n(t r ) can be modeled as a form of single-frequency signal synthesis within the noise spectral bandwidth:

[0057]

[0058] where A i,r is the amplitude of each single-frequency signal within the noise spectral bandwidth.

[0059] Substituting n(t r ) into the equation yields:

[0060]

[0061] Due to the orthogonality between the signals transmitted by different channels, at the receiving end of the MIMO radar, the echo signal components corresponding to the signals transmitted by different channels can be screened by a matched filter set, and the unrelated echo components can be suppressed while the intra-pulse energy is accumulated by pulse compression. Assuming that the MIMO radar transmits an LFM signal with a bandwidth B, for the signal transmitted by the i-th array element, the result after pulse compression using the reference signal h i (t r ) can be represented as:

[0062]

[0063] The linear frequency modulation signal is a typical pulse compression signal, and after matched filtering, a narrow-width sinc function can be output, which can be approximated as a delta function:

[0064]

[0065] After slow-time FFT, the velocity dimension interference result can be approximated as:

[0066]

[0067] The two-dimensional interference result in the range and velocity dimensions can be represented as:

[0068]

[0069] The interference imaging result is approximately the synthesis of a large number of impulse functions, the positions of which are determined by the frequency points of the noise template, the interference center is (2τ0+τ j ,f d ), and the interference range depends on the fast-time and slow-time bandwidths of the template. Therefore, the frequency domain design of the noise template can directly affect the final effect of the interference.

[0070] The two-dimensional smart interference result is simulated according to the parameters in Table 1 below to demonstrate the technical advantages of the present application.

[0071] Table 1 Parameter Settings

[0072]

[0073] Figure 4 The results of the two-dimensional smart noise interference after MTD are shown, and it can be clearly seen that the interference energy is distributed in the range dimension and the velocity dimension. In order to more clearly demonstrate the interference effect of the two-dimensional smart noise, Figure 5 is a result graph in the range dimension without interference, Figure 6 is a result graph in the range dimension with interference, Figure 7 is a result graph in the velocity dimension without interference, Figure 8The figure is the velocity dimension result of the velocity dimension result. It can be seen that compared with the traditional distance dimension smart jamming, the energy of the traditional distance dimension smart jamming is only expanded along the distance dimension, when there are multiple targets and the speeds of the targets are different, the targets can still be detected due to the absence of the velocity dimension jamming, the energy of the two-dimensional smart jamming is expanded along the distance and velocity dimensions, and the jamming effect and the covering range are larger.

[0074] Figure 9 The figure is the two-dimensional smart noise jamming MTD of the noise template with a fast time bandwidth of 10 MHz and a slow time bandwidth of 10 KHz. It can be seen from the figure that when the fast time bandwidth and the slow time bandwidth of the noise template are increased, the jamming energy has a larger covering range.

[0075] The theoretical analysis and the simulation experiment show the effectiveness of the two-dimensional smart noise jamming based on the centralized MIMO radar provided by the embodiments of the present application.

[0076] Consider that a MIMO radar will detect a moving target in a to-be-detected airspace, and the MIMO radar jamming scene is as shown in Figure 3 The fleet flies along the horizontal direction at a position 340 km away from the radar, and there is one jammer with a speed of 88 m / s and two to-be-protected aircrafts with speeds of 80 m / s and 95 m / s respectively. The MIMO radar has 8 transmitting antennas and 8 receiving antennas, transmits a rectangular pulse signal to detect the target at a pulse repetition frequency of 10 kHz, the carrier frequency is 4 GHz, the total power of the MIMO radar array is 500 KW, when the two-dimensional smart noise jamming is not applied, the target MTD is as shown in Figure 10 When the jammer power is 10 W and the transmitting antenna gain of the jammer is 3 dB, the target MTD is as shown in Figure 11 The simulation result shows that the target is completely submerged by the noise.

[0077] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

[0078] The above is only some embodiments of the present application. For those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application.

Claims

1. A method for two-dimensional smart noise jamming based on centralized MIMO radar, characterized in that, The method comprises the following steps: Step 1, the jammer intercepts the radar transmitting signal according to the digital radio frequency memory, performs down-conversion processing on the radar transmitting signal, and periodically samples each pulse of the signal transmitted by the enemy to form multiple slices through intermittent sampling; The MIMO radar has M transmitting elements, each channel transmits mutually orthogonal signals, and the transmitting signal is represented as: where t r represents fast time, f c is the carrier frequency, s i (t r ) represents the transmit signal of the i-th element; When the jammer intercepts the MIMO transmitting signal, the jammer first performs down-conversion processing on the MIMO transmitting signal to obtain a baseband intercepted signal: where t a represents a slow time, represents a convolution operation, τ(t a ) = (R0-vt a ) / c represents a one-way delay of the MIMO radar jammer, R0 and v respectively represent an initial slant range and a radial velocity of the jammer relative to the MIMO radar, and c is a light speed; Step 2, the jamming signal is modulated by a noise frequency modulation signal in the range dimension and the velocity dimension, wherein the noise frequency modulation signal is: where u(t) is a generalized stationary random signal with zero mean, U j is the amplitude of the jamming signal, φ is uniformly distributed in [0, 2π] and is independent of u(t), ω j is the center frequency of the jamming, K FM is the slope of the frequency modulation, representing the frequency change per unit of the modulating signal strength; The jammer multiplies the intercepted signal with a locally pre-generated noise template n(t r ,t a ) to obtain a modulated jamming signal: m(t r ,t a ) = n(t r ,t a ) s in (t r ,t a ) In the formula, the noise template is non-correlated in both fast time dimension and slow time dimension; the single side bandwidth of the corresponding dimension is B nr and B na ; by adjusting the noise bandwidth of the corresponding dimension, the distribution of the dense false target in the distance dimension and the velocity dimension is controlled; Step 3, the jammer performs up-conversion processing on the modulated signal to form a retransmission type two-dimensional smart noise jamming signal: where τ j is the fixed retransmission delay of the jammer.

2. The method of claim 1, wherein, The method further comprises: under the action of the jamming signal, the result obtained by the centralized MIMO radar according to a signal processing procedure, including range dimension matching filtering and velocity dimension FFT operation; due to the smart noise design of the jamming signal in the range dimension and the velocity dimension, dense false targets appear in the detection result of the radar, and the echo signal of the real target is covered or interfered.

3. The method of claim 2, wherein, The baseband jamming signal received by the MIMO radar is represented as: s jr (t r ) and s ja (t a ) denote the range and velocity components of the echo at the jammer, respectively. Wherein T0= R0 / c is the initial one-way delay, f d = 2v / λ is the Doppler frequency, λ is the transmitted signal wavelength.

4. The method of claim 3, wherein, The MIMO radar performs matching filtering sampling on each fast time sampling unit of the jamming signal, and the range dimension interference model is represented as: r(t r ) = n(t r )s jr (t r ) n(t r ) is modeled as a synthesis of single-frequency signals within a spectral bandwidth: where A i,r is the amplitude of each single frequency signal within the noise spectrum bandwidth; Substituting n(t r ) into the equation gives: The result of the pulse compression of h i (t r ) is denoted by The linear frequency modulation signal is a pulse compression signal, and after matching filtering, a narrow-width sinc function is output, which is approximately a delta function: After slow-time FFT, the velocity dimension interference result is approximately: The two-dimensional interference result in the range and velocity dimensions is represented as: The result of the interference imaging is approximately the composition of a number of impulse functions whose positions are determined by the frequency of the noise template, the interference center is (2τ0+τ j ,f d ), and the interference range depends on the fast and slow time bandwidth of the template.

5. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the steps of the method of any one of claims 1-4 when executing the program.

6. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to implement the steps of the method of any one of claims 1-4.

7. A computer program product comprising a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method of any one of claims 1-4. The computer program is executed by the processor to implement the steps of the method of any one of claims 1-4.

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