Two-dimensional smart noise interference method based on centralized MIMO radar

Abstract

The invention discloses a two-dimensional smart noise interference method based on a centralized MIMO radar, and belongs to the technical field of radar communication.The method comprises the steps that down-conversion processing is carried out on radar transmitting signals intercepted by a digital radio frequency memory through a jammer, and the radar transmitting signals are subjected to down-conversion processing; periodic sampling is carried out on each pulse of a signal transmitted by an enemy through intermittent sampling to form a plurality of slices, then smart noise interference modulation is carried out in a distance dimension and a speed dimension, and finally, up-conversion processing is carried out on a modulation signal, so that a forwarding type two-dimensional smart noise interference signal is formed. After an MIMO radar receives an interference signal, a result obtained by a conventional signal processing method is seriously influenced by the interference signal generated in the invention. According to the method, smart noise interference is applied to an enemy radar signal in the distance dimension and the speed dimension, and an intensive false target is successfully generated, so that the detection of the MIMO radar on a real target is interfered.

Description

Technical Field

[0001] The present invention relates to the field of radar communication technology, and in particular to a two-dimensional smart noise jamming method based on centralized MIMO radar. Background Art

[0002] Multiple Input Multiple Output (MIMO) radar has become an important development direction of modern radar systems due to its advantages of high resolution, multi-target detection capability and spatial freedom. However, with the widespread application of MIMO radar technology in military and civilian fields, it has also become a key target of electronic countermeasures. The design of jamming signals for MIMO radar is an important countermeasure in electronic warfare. The purpose is to weaken or destroy the detection performance of the radar through specially designed jamming signals, so as to mislead or mask the target.

[0003] Deception jamming is a key method to design jamming signals based on radar echo characteristics. Common methods include delay deception, frequency shift deception and Doppler deception. For MIMO radar, a signal similar to its transmitted waveform but containing deviation information can be generated to mislead the radar's distance and speed estimation. Due to the complex processing capabilities of MIMO radar, a single type of jamming is often difficult to work. The combined use of noise jamming, deception jamming and space jamming and other strategies can effectively improve the success rate of jamming.

[0004] The design of MIMO radar jamming signals needs to combine the characteristics of the radar system and the countermeasure target, and comprehensively consider the strength, directionality, spectrum 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 in the development of modern electronic warfare. Summary of the invention

[0005] The purpose of the present invention is to provide a two-dimensional smart noise jamming method based on a centralized MIMO radar. The use of smart jamming signals can obtain a larger accumulated gain at the MIMO radar receiving end and has a higher jamming power utilization rate. Through the two-dimensional smart noise jamming of the present invention, interference can be generated simultaneously in the distance dimension and the speed dimension to better protect the target.

[0006] The technical solution of the present invention is: 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 transmission 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, performing smart noise interference modulation in the distance dimension and the speed dimension respectively;

[0009] Step 3: Up-convert the modulated signal to form a forwarding two-dimensional smart noise interference signal.

[0010] Furthermore, under the influence of interference signals, the centralized MIMO radar obtains results according to the signal processing process, including distance dimension matched filtering and speed dimension FFT operations; due to the clever noise design of the interference signal in the distance dimension and speed dimension, dense false targets will appear in the radar's detection results, and the echo signals of the real targets will be masked or interfered.

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

[0012] A computer-readable storage medium stores a computer program, which implements the steps of the above method when executed by a processor.

[0013] A computer program product comprises a computer program, which implements the steps of the above method when executed by a processor.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: the two-dimensional smart noise interference signal designed in the present invention, after MIMO radar signal processing, a single jammer can simultaneously generate dense false targets in the distance dimension and the speed dimension, which is impossible to achieve with traditional interference signals; and by adjusting the two-dimensional noise signal bandwidth, 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 THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 The figure is a flow chart of a two-dimensional smart noise jamming method based on centralized MIMO radar.

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

[0018] Figure 3 This is a diagram of the MIMO radar interference scenario.

[0019] Figure 4It is the two-dimensional smart noise interference MTD diagram.

[0020] Figure 5 This is the distance dimension result diagram when there is no interference.

[0021] Figure 6 This is the distance dimension result diagram when there is interference.

[0022] Figure 7 This is the speed dimension result diagram when there is no interference.

[0023] Figure 8 This is the speed dimension result diagram when there is interference.

[0024] Fig. 9 The two-dimensional smart noise interference MTD diagram under different noise bandwidths.

[0025] Fig.10 It is the MTD diagram of multiple targets without two-dimensional smart noise interference.

[0026] Fig.11 It is the MTD diagram of multiple targets under two-dimensional smart noise interference. DETAILED DESCRIPTION

[0027] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in detail and completely in conjunction with the drawings in the implementation of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings can be arranged and designed using different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present invention.

[0028] The present invention discloses a two-dimensional smart noise jamming method based on a centralized MIMO radar, which belongs to the field of radar communication technology. The present invention first uses a jammer to intercept a radar transmission signal according to a digital radio frequency memory, performs down-conversion processing on it, performs periodic sampling on each pulse of the signal transmitted by the enemy through intermittent sampling to form multiple slices, and then performs smart noise interference modulation in the distance dimension and the speed dimension respectively. Finally, the modulated signal is subjected to up-conversion processing to form a forwarding two-dimensional smart noise jamming signal. After the MIMO radar receives the jamming signal, the result obtained by the conventional signal processing method will be seriously affected by the jamming signal generated in the present invention. The present invention successfully generates dense false targets by applying smart noise jamming to the enemy radar signal in the distance dimension and the speed dimension, thereby interfering with the detection of the real target by the MIMO radar. This jamming effect depends on the design of the two-dimensional smart noise jamming signal, which is difficult to achieve with traditional jamming technology. In addition, by adjusting the bandwidth of the noise signal, the present invention can produce specific jamming effects according to different combat requirements, thereby effectively covering its own echo signal and improving the penetration capability.

[0029] Combination Figure 1 The embodiment of the present invention provides a two-dimensional smart noise jamming method based on a centralized MIMO radar, wherein a jammer including a jammer receiver and a digital radio frequency memory performs the following processing on the radar signal:

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

[0031] Step J2, performing smart noise interference modulation in the distance dimension and the speed dimension respectively;

[0032] Step J3, up-converting the modulated signal to form a forwarding two-dimensional smart noise interference signal;

[0033] Step J4, under the interference signal, the centralized MIMO radar obtains the result according to the conventional signal processing flow, including distance dimension matched filtering, speed dimension FFT and other operations. However, due to the clever noise design of the interference signal in the distance dimension and speed dimension, dense false targets will appear in the radar detection results, and the echo signal of the real target will be covered or interfered.

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

[0035]

[0036] Where, t r Indicates fast time, f c is the carrier frequency, si(tr) represents the transmitted signal of the i-th array element.

[0037] When the jammer intercepts the MIMO transmission signal, it first performs down-conversion processing to obtain the baseband intercepted signal:

[0038]

[0039] where t a Indicates slow time, represents the convolution operation, τ(t a )=(R0-vt a ) / c represents the one-way delay from 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, and c is the speed of light.

[0040] In step J2, the noise signals in the distance dimension and the speed dimension are noise frequency modulation signals:

[0041]

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

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

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

[0045] In the formula, the noise template is non-correlated in both the fast time dimension and the slow time dimension. The unilateral bandwidth of the corresponding dimension is B nr and B na By adjusting the noise bandwidth of the corresponding dimension, the distribution of dense false targets in the distance dimension and the speed dimension can be flexibly controlled.

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

[0047]

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

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

[0050]

[0051] in

[0052]

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

[0054] In step J4, the MIMO radar performs matched filtering sampling on each fast time sampling unit of the interference signal. At this time, the distance dimension interference 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 single-frequency signal synthesis within the spectrum bandwidth:

[0057]

[0058] Among them, A i,r is the amplitude of each single frequency signal within the noise spectrum bandwidth.

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

[0060]

[0061] Due to the orthogonality between the transmission signals of different channels, the echo signal components corresponding to each transmission signal can be screened by a matched filter group at the receiving end of the MIMO radar, and irrelevant echo components can be suppressed while accumulating the energy in the pulse during pulse compression. Assuming that the MIMO radar transmission signal is an LFM signal with a bandwidth of B, for the transmission signal of the i-th array element, the reference signal h i (t r ) The result after pulse compression can be expressed as:

[0062]

[0063] The linear frequency modulation signal is a typical pulse compression signal. After matched filtering, it can output a narrow sinc function form, 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] Then the two-dimensional interference results of distance and speed dimensions can be expressed as:

[0068]

[0069] The interference imaging result is approximately the synthesis of countless impulse functions, whose position is 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. Therefore, the frequency domain design of the noise template can directly affect the final effect of the interference.

[0070] The following two-dimensional smart jamming results are simulated according to the parameters in Table 1 to demonstrate the technical advantages of the present invention.

[0071] Table 1 Parameter settings

[0072]

[0073] Figure 4 The results of two-dimensional smart noise interference after MTD are shown. It can be clearly seen that the interference energy is distributed in both the distance dimension and the speed dimension. In order to more clearly show the interference effect of two-dimensional smart noise, Figure 5 This is the distance dimension result diagram when there is no interference. Figure 6 This is the distance dimension result diagram when there is interference. Figure 7 This is the velocity dimension result diagram when there is no interference. Figure 8The speed dimension result diagram when there is interference. It can be seen that compared with the traditional distance dimension smart jamming, the traditional distance dimension smart jamming energy only expands along the distance dimension. When there are multiple targets with different speeds, the targets can still be detected because there is no interference in the speed dimension. The two-dimensional smart jamming energy expands along both the distance and speed dimensions, with a larger coverage range and interference effect.

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

[0075] The above theoretical analysis and simulation experiments illustrate the effectiveness of the two-dimensional smart noise jamming based on centralized MIMO radar provided by the embodiments of the present invention.

[0076] Consider a MIMO radar that will detect moving targets in the airspace to be detected. The MIMO radar interference scenario is as follows: Figure 3 As shown. The fleet is flying horizontally at a distance of 340km from the radar. There is a jammer with a speed of 88m / s and two aircraft to be covered with speeds of 80m / s and 95m / s respectively. The MIMO radar has 8 transmitting antennas and 8 receiving antennas. It transmits rectangular pulse signals at a pulse repetition frequency of 10kHz to detect targets. The carrier frequency is 4GHz. The total power of the MIMO radar array is 500KW. When no two-dimensional smart noise interference is applied, the target MTD diagram is as follows Fig.10 As shown in the figure, when the jammer power is 10W and the jammer transmitting antenna gain is 3dB, the target MTD diagram is as follows Fig.11 As shown in the simulation results, we can see 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 invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0078] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A two-dimensional smart noise jamming method based on centralized MIMO radar, characterized in that: The steps include: Step 1: The jammer performs down-conversion processing on the radar transmission 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; Step 2, performing smart noise interference modulation in the distance dimension and the speed dimension respectively; Step 3: Up-convert the modulated signal to form a forwarding two-dimensional smart noise interference signal.

2. The method according to claim 1, characterized in that The method also includes: under the action of the interference signal, the centralized MIMO radar obtains the results according to the signal processing process, including distance dimension matching filtering and speed dimension FFT operations; due to the smart noise design of the interference signal in the distance dimension and speed dimension, dense false targets will appear in the radar's detection results, and the echo signal of the real target will be covered or interfered.

3. The method according to claim 1, characterized in that In step J1, the MIMO radar has M transmitting array elements, and each channel transmits mutually orthogonal signals, so the transmitting signal is expressed as: Where, t r Indicates fast time, f c is the carrier frequency, si(tr) represents the transmitted signal of the ith array element; When the jammer intercepts the MIMO transmission signal, it first performs down-conversion processing to obtain the baseband intercepted signal: where t a Indicates slow time, represents the convolution operation, τ(t a )=(R0-vt a ) / c represents the one-way delay from 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, and c is the speed of light.

4. The method according to claim 3, characterized in that The interference signal is modulated by noise frequency modulation signals in the distance dimension and the speed dimension respectively, where the noise frequency modulation signal is: In the formula, the modulated noise signal u(t) is a wide-sense stationary random signal with a mean of zero, U j is the interference signal amplitude, initial phase is uniformly distributed on [0,2π] and is independent of u(t), ω j is the interference center frequency, K FM It is the slope of frequency modulation, which indicates the frequency change caused by the modulation signal of unit intensity; The jammer combines the intercepted signal with the locally pre-generated noise template n(t r ,t a ) are multiplied to obtain the modulated interference 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 the fast time dimension and the slow time dimension; the unilateral bandwidth of the corresponding dimension is B nr and B na ; By adjusting the noise bandwidth of the corresponding dimension, the distribution of dense false targets in the distance dimension and speed dimension is controlled.

5. The method according to claim 4, characterized in that The jammer up-converts the modulated signal to form a forwarding two-dimensional smart noise jammer signal: Among them, τ j is the fixed forwarding delay of the jammer; s jr (t r ) and s ja (t a ) represent the distance dimension and velocity dimension echo components at the jammer respectively.

6. The method according to claim 5, characterized in that The baseband interference signal received by the MIMO radar is expressed as: s jr (t r ) and s ja (t a ) represent the distance dimension and velocity dimension echo components at the jammer respectively; in τ0=R0 / c is the initial one-way delay, f d =2v / λ is the Doppler frequency, λ is the wavelength of the transmitted signal.

7. The method according to claim 6, characterized in that The MIMO radar performs matched filtering sampling on each fast time sampling unit of the interference signal, and the distance dimension interference model is expressed as: r(t r )=n(t r )s jr (t r ) n(t r ) is modeled as a single-frequency signal synthesis within the spectrum bandwidth: Among them, A i,r is the amplitude of each single frequency signal within the noise spectrum bandwidth; n(t r ) into the equation: Using the reference signal h i (t r ) The result after pulse compression is expressed as: The linear frequency modulation signal is a pulse compression signal. After matched filtering, the output width is a narrow sinc function, which is approximately a delta function: After slow-time FFT, the velocity dimension interference result is approximately: Then the two-dimensional interference results of distance and speed dimensions are expressed as: The interference imaging result is approximately the synthesis of countless impulse functions, whose position is 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.

8. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the method according to any one of claims 1 to 7 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method described in any one of claims 1 to 7 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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