Multi-false-target smart interference method and system based on noise template linear modulation

Abstract

The invention discloses a multi-signal detection method and system based on multi-phase filtering and STFT. The multi-signal detection method based on multi-phase filtering and STFT comprises the following steps: acquiring an intercepted signal; performing digital down-conversion processing on the intercepted signal; and carrying out product modulation on the intercepted signal subjected to digital down-conversion processing and an offline generated noise template to generate an interference signal. The invention discloses a multi-false-target smart interference method based on noise template linear modulation. The method comprises the following steps: firstly, acquiring an intercepted signal, and then carrying out digital down-conversion processing on the intercepted signal; and then product modulation is carried out on the intercepted signal subjected to digital down-conversion processing and an offline generated noise template to generate an interference signal, so that a multi-false target interference effect of any number and position can be generated only by carrying out online one-step product on the intercepted signal, the modulation is simpler, the interference effect is flexible and variable, and the interference efficiency is improved. And the number of hardware resources is reduced.

Description

Technical Field

[0001] The present invention relates to the field of electronic countermeasure technology, and in particular to a method and system for smart jamming of multiple false targets based on offline modulation of noise templates. Background Art

[0002] Since radar was used as a "spear" in war, electronic jamming technology has been applied to various weapon platforms such as sea, land, and air. Without interference, there is no launch. Electronic jamming technology provides a strong technical guarantee for our army's important deployment and military operations, and provides strong support for the "information control" in the complex electromagnetic spectrum space. The existing multi-false target jamming is achieved by cascading multiple delay units. The number of false targets is linearly related to hardware resources. However, when the number of false targets is large, the amount of hardware resources will increase sharply, resulting in great pressure on hardware resources. In addition, delay modulation will cause false targets to always lag behind real targets, which are easily identified and suppressed by advanced radar signal processing algorithms, resulting in poor interference effects of multiple false targets. Summary of the invention

[0003] The purpose of the present invention is to design a multi-false target smart jamming method based on noise template offline modulation in order to solve the above problems.

[0004] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0005] A smart jamming method for multiple false targets based on offline modulation of noise templates includes:

[0006] Acquire intercepted signals;

[0007] Performing digital down-conversion processing on the intercepted signal;

[0008] The intercepted signal that has completed the digital down-conversion process is multiplied and modulated with a noise template generated offline to generate an interference signal.

[0009] The present invention also proposes a multi-false target smart jamming system based on noise template offline modulation, the multi-false target smart jamming system based on noise template offline modulation includes a jammer, and the multi-false target smart jamming system based on noise template offline modulation is used to implement the above-mentioned multi-false target smart jamming method based on noise template offline modulation.

[0010] The beneficial effects of the present invention are:

[0011] The multi-false target smart jamming method based on offline modulation of noise template first obtains the intercepted signal, and then performs digital down-conversion processing on the intercepted signal; then the intercepted signal that has completed the digital down-conversion processing is multiplied and modulated with the noise template generated offline to generate an interference signal, thereby achieving the effect of multiple false targets of any number and position by only performing one step of online multiplication on the intercepted signal. The modulation is simpler, the interference effect is flexible and variable, and the amount of hardware resources is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a flow chart of the method for smart jamming of multiple false targets based on offline modulation of noise templates of the present invention;

[0013] Figure 2 It is a schematic diagram of interference modulation of the smart interference method of multiple false targets based on noise template offline modulation of the present invention;

[0014] Figure 3 This is a diagram showing the interference effect of the smart interference method for multiple false targets based on noise template offline modulation according to the present invention;

[0015] FIG4 (a) is a diagram showing the deception effect of six equally spaced false targets generated by the multiple false target smart jamming method based on offline modulation of a noise template of the present invention;

[0016] FIG4 (b) is a diagram showing the deception effect of four false targets at designated locations produced by the multiple false target smart jamming method based on offline modulation of noise templates of the present invention;

[0017] Figure 5 This is a diagram showing the suppression effect of dense false targets produced by the multiple false target smart jamming method based on offline modulation of noise templates in the present invention. DETAILED DESCRIPTION

[0018] In order 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 clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0021] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use, or are directions or positional relationships commonly understood by those skilled in the art. These directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0022] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0023] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms such as "setting" and "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings.

[0025] like Figure 1-5 As shown, the multi-false target smart jamming method based on noise template offline modulation includes:

[0026] Acquire intercepted signals;

[0027] Performing digital down-conversion processing on the intercepted signal;

[0028] The intercepted signal that has completed the digital down-conversion process is multiplied and modulated with a noise template generated offline to generate an interference signal.

[0029] In one embodiment, the step of generating a noise template online is specifically as follows:

[0030] Perform FFT transformation on the initial noise template n0(t) to the frequency domain to generate an initial frequency domain template n0(f);

[0031] Generate frequency domain sampling function according to the number and position requirements of false targets , Q is the frequency point set corresponding to the false target position;

[0032] The initial frequency domain template n0(f) is sampled in the frequency domain to generate a frequency domain template ;

[0033] The frequency domain template n(f) is transformed into the time domain by IFFT to generate the noise template n(t).

[0034] In this embodiment, when the jammer is illuminated by the radar beam, it detects and intercepts it to obtain the intercepted signal; the jammer first performs digital down-conversion processing on the intercepted signal, that is, the sampling rate of the intercepted signal is reduced to a lower frequency through the extractor, thereby reducing the number of noise template points, reducing the consumption of hardware resources, and thus reducing power consumption; the jammer then directly multiplies the intercepted signal after digital down-conversion processing with the noise template that has been pre-generated offline to generate an interference signal, that is, the noise template is generated in an offline state. On the basis of not changing the modulation process, only one step of online multiplication of the intercepted signal is required to achieve the dual interference effect of deception and suppression of false targets at any position and number. The simulation results are shown in FIG. Figure 3 ,As can be seen from the figure, from the point of view of the number and position of false ,targets, the interference modulation method can produce any position and number of false ,targets ahead of the real target, and the interference effect is better.

[0035] In this embodiment, the steps of generating a noise template in an offline state are as follows: generating an initial noise template n0(t), first transforming it to the frequency domain through FFT (fast Fourier transform) to generate an initial frequency domain template n0(f); then generating a frequency domain sampling function according to the number and position requirements of false targets , where Q is the frequency point set corresponding to the false target position; then, the initial frequency domain template n0(f) is sampled in the frequency domain to generate the frequency domain template ; Finally, the frequency domain template n(f) is transformed to the time domain by IFFT (Inverse Fast Fourier Transform) to generate the noise template n(t). Among them, frequency domain sampling can filter out the frequency points of false targets at specified positions, and the calculation formula for the specified frequency point position in the frequency point set is: , where f r is the frequency point position of the false target, c is the speed of light, k r is the frequency modulation slope of the radar signal, R f is the position of the false target relative to the jammer, thereby realizing the design of the false target position. Therefore, the noise template is generated in an offline state, and the online modulation of the intercepted signal only requires one time domain multiplication, and the jamming method has better real-time performance.

[0036] The multi-false target smart jamming method based on offline modulation of noise template of the present invention first obtains the intercepted signal, and then performs digital down-conversion processing on the intercepted signal; then performs product modulation on the intercepted signal that has completed the digital down-conversion processing and the noise template generated offline to generate an interference signal, thereby achieving the multi-false target jamming effect of any number and position by only performing one step of online multiplication on the intercepted signal, the modulation is simpler, the jamming effect is flexible and variable, and the amount of hardware resources is reduced.

[0037] In one embodiment, the step of generating the noise template n(t) is specifically:

[0038] Multiple single-frequency signals in the noise modeling spectrum are synthesized into the noise template n(t):

[0039] , f i is the frequency of the i-th single-frequency signal.

[0040] In one embodiment, the step of performing digital down-conversion processing on the intercepted signal is specifically as follows:

[0041] The intercepted signal is extracted and preprocessed to output a baseband signal s in (t).

[0042] In one embodiment, the step of performing product modulation of the intercepted signal that has completed the digital down-conversion processing with the noise template generated offline to generate the interference signal is specifically as follows:

[0043] The baseband signal s in (t) is modulated by product with the noise template n(t): , generating the interference signal .

[0044] In one embodiment, the generating of the interference signal The specific steps are:

[0045] The interference signal is remodeled as ;

[0046] According to the time-frequency coupling of the linear frequency modulation signal, the interference signal pulse is compressed into ;

[0047] Replace the sin c function with the delta function to obtain the interference signal .

[0048] The modulation principle of the multi-false target smart jamming method based on noise template offline modulation in this embodiment is as follows: When the jammer is illuminated by the radar beam, it conducts reconnaissance and intercepts it and performs digital down-conversion processing to obtain the baseband signal s in (t).

[0049] Next, the jammer multiplies the intercepted signal with the noise template n(t) that has been generated offline in advance, that is, ; Synthesize numerous single-frequency signals in the noise modeling spectrum to obtain a noise template , where f i represents the frequency of the i-th single-frequency signal. Based on this, the interference signal is remodeled as It can be seen that the above formula represents the countless frequency shift modulation and accumulation of the target echo; according to the time-frequency coupling of the linear frequency modulation signal, the interference signal pulse is compressed into ; In view of the large bandwidth of general radar signals, the sin c(·) function in the above formula can be approximated as the δ(·) function, so the interference effect is a collection of countless impulse functions, thus obtaining the interference signal It can be seen that the jamming method makes full use of the time-frequency coupling of the linear frequency modulation signal and the bilateral spectrum of the noise template. The jamming result is a set of countless impulse functions that spread forward and backward with the target echo as the center.

[0050] In this embodiment, the radar transmitting signal is a linear frequency modulation waveform with a signal width of 10us and a signal bandwidth of 200MHz. Without loss of generality, considering that the target is 5500m away from the radar, the jammer adopts a self-defense jamming mode. According to the multi-false target smart jamming method based on offline modulation of the noise template proposed by the present invention, 6 false targets with equal intervals of 150m are set in the noise template generated offline, and the jamming result is shown in Figure 4 (a); in the radar pulse compression result, the false targets are distributed before and after the real target; the number of false targets is changed to 4, and the positions of the false targets are designed to be 5100m, 5300m, 5450m and 6000m respectively. The jamming effect is shown in Figure 4 (b), achieving the deception effect of any position and number of false targets. If other parameters are kept unchanged and only the offline noise template is modified, a total of 101 false target groups with intervals of 10m are generated, as shown in Figure 4 (a). Figure 5 As shown in the figure, a large number of false target groups are distributed in front and behind the real target, achieving a dense false target suppression effect with the target as the center and an interference range of 1000m.

[0051] The present invention also proposes a multi-false target smart jamming system based on noise template offline modulation, the multi-false target smart jamming system based on noise template offline modulation includes a jammer, the multi-false target smart jamming system based on noise template offline modulation is used to implement the above-mentioned multi-false target smart jamming method based on noise template offline modulation; the specific structure of the multi-false target smart jamming method based on noise template offline modulation refers to the above-mentioned embodiment, since the multi-false target smart jamming system based on noise template offline modulation adopts all the technical solutions of all the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which are not elaborated here one by one.

[0052] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A multi-false target smart jamming method based on noise template offline modulation, characterized in that: The multi-false target smart jamming method based on noise template offline modulation comprises the following steps: Acquire intercepted signals; Performing digital down-conversion processing on the intercepted signal; The intercepted signal that has completed the digital down-conversion process is multiplied and modulated with a noise template generated offline to generate an interference signal.

2. The multi-false target smart jamming method based on noise template offline modulation according to claim 1 is characterized in that: The steps of generating the noise template online are specifically as follows: Generate an initial noise template n0(t), and perform FFT transformation on the initial noise template n0(t) to the frequency domain to generate an initial frequency domain template n0(f); Generate frequency domain sampling function according to the number and position requirements of false targets , Q is the frequency point set corresponding to the false target position; The initial frequency domain template n0(f) is sampled in the frequency domain to generate a frequency domain template ; The frequency domain template n(f) is transformed into the time domain by IFFT to generate the noise template n(t).

3. The multi-false target smart jamming method based on noise template offline modulation according to claim 2 is characterized in that: The steps of generating the noise template n(t) are specifically as follows: Multiple single-frequency signals in the noise modeling spectrum are synthesized into the noise template n(t): , f i is the frequency of the i-th single-frequency signal.

4. The multi-false target smart jamming method based on noise template offline modulation according to claim 3 is characterized in that: The steps of performing digital down-conversion processing on the intercepted signal are specifically as follows: The intercepted signal is extracted and preprocessed to output a baseband signal s in (t).

5. The method for smart jamming of multiple false targets based on noise template offline modulation according to claim 4 is characterized in that: The step of performing product modulation of the intercepted signal after the digital down-conversion processing and the noise template generated offline to generate the interference signal is specifically as follows: The baseband signal s in (t) is modulated by product with the noise template n(t): , generating the interference signal .

6. The multi-false target smart jamming method based on noise template offline modulation according to claim 5 is characterized in that: generating the interference signal The specific steps are: The interference signal is remodeled as ; According to the time-frequency coupling of the linear frequency modulation signal, the interference signal is pulse compressed to ; Replace the sin c function with the delta function to obtain the interference signal .

7. A multi-false target smart jamming system based on noise template offline modulation, characterized in that: The multiple false target smart jamming system based on noise template offline modulation includes a jammer, and the multiple false target smart jamming system based on noise template offline modulation is used to implement the multiple false target smart jamming method based on noise template offline modulation as described in any one of claims 1-6.

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