Multi-dimensional agile radar anti-interference waveform design method and system

Abstract

The invention discloses a multi-dimensional agile radar anti-interference waveform design method and system, and the method comprises the steps: S10, separating a target echo and an interference signal from a primary receiving signal, and estimating an interference signal parameter from the interference signal; s20, designing a generalized distance according to the interference signal parameters; step S30, repeating the step S10 to obtain the degree of freedom of the interference signal parameter, and obtaining an anti-interference multi-dimensional agile waveform parameter according to the degree of freedom of the interference signal parameter and a preset degree of freedom of the multi-dimensional agile waveform parameter; and S40, with the maximization of the generalized distance as a target and the anti-interference multi-dimensional agile waveform parameter as a constraint condition, obtaining a multi-dimensional agile radar anti-interference waveform. According to the method, the problem that novel deception forwarding interference of intermittent sampling interference cannot be resisted is solved, and the anti-interference capability of the radar is further improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of radar waveform design, and in particular relates to a multi-dimensional agile radar anti-interference waveform design method and system. Background Art

[0002] The traditional method to increase the complexity of the transmitted waveform is to transmit an agile frequency waveform. The agile frequency waveform is a waveform in which the center frequency changes rapidly over time. When the interference forwarding time is longer than the repetition time of a pulse, the false signal forwarded by DRFM does not match the center frequency of the next transmitted signal and cannot be mixed. Therefore, the agile frequency waveform has a strong ability to resist forwarding interference. Currently, most anti-interference is achieved by designing an agile frequency waveform.

[0003] However, with the development of jamming technology, traditional forwarding jamming has been replaced by intermittent sampling jamming, which achieves rapid forwarding by sampling part of the intercepted signal. The duration of the entire process is less than a pulse repetition time, and a forwarding waveform containing a false target can be generated within a pulse to implement coherent false target jamming. Because the frequency-agile waveform does not change within a pulse time, it cannot resist intermittent sampling jamming. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to provide a multi-dimensional agile radar anti-interference waveform design method and system, to solve the problem of new deceptive forwarding interference that cannot resist intermittent sampling interference, and to further enhance the radar's anti-interference capability.

[0005] The object of the present invention is achieved through the following technical solutions: a multidimensional agile radar anti-interference waveform design method, comprising: step S10: separating the target echo and the interference signal from a received signal, and estimating the interference signal parameters from the interference signal; step S20: designing a generalized distance according to the interference signal parameters; step S30: repeating step S10 to obtain the degrees of freedom of the interference signal parameters, and obtaining the multidimensional agile waveform parameters that can resist interference according to the degrees of freedom of the interference signal parameters and the preset degrees of freedom of the multidimensional agile waveform parameters; step S40: taking maximizing the generalized distance as the goal and taking the multidimensional agile waveform parameters that can resist interference as the constraints, to obtain the multidimensional agile radar anti-interference waveform.

[0006] In the above-mentioned multi-dimensional agile radar anti-interference waveform design method, separating the target echo and the interference signal from a received signal includes the following steps: whitening the received signal to obtain a whitened signal; estimating the fourth-order cumulant matrix of the whitened signal, and solving the unmixing matrix by joint diagonalization; multiplying the unmixing matrix and the whitened signal to extract the source signal component in the received signal; matching filtering the source signal component and the agile frequency waveform transmitted this time, and the source signal component with a peak output is the target echo, and the target echo is subtracted from the received signal to obtain the interference signal.

[0007] In the above-mentioned multi-dimensional agile radar anti-interference waveform design method, the interference signal parameters are obtained by the following formula:

[0008]

[0009] in, is the interference signal parameter, G(t,f,s,p) is the interference signal, L{} is the likelihood function, is the interference parameter vector, t, f, s, p represent time, frequency, space and codeword variables respectively.

[0010] In the above-mentioned multi-dimensional agile radar anti-interference waveform design method, the generalized distance is obtained by the following formula:

[0011]

[0012] Among them, R<T,G> is the generalized distance, t, f, s, p represent time, frequency, space and codeword variables respectively, Θ T , Θ S , Θ F , Θ P are the time interval, space interval, frequency interval, and code interval of the waveform respectively, I(·) is the indicative function, G(t,f,s,p) is the interference signal, T is the target echo factor, G is the interference signal factor, and T * (t,f,s,p) is the complex conjugate of T(t,f,s,p).

[0013] In the above-mentioned multi-dimensional agile radar anti-interference waveform design method, the degree of freedom of the interference signal parameters is obtained by the following formula:

[0014]

[0015] in, is the degrees of freedom of the interference signal parameters, is the first interference signal parameter, is the second interference signal parameter, The Nth interference signal parameter, where N is the total number of confrontations.

[0016] In the above-mentioned multi-dimensional agile radar anti-interference waveform design method, the anti-interference multi-dimensional agile waveform parameters are obtained by the following formula:

[0017]

[0018] in, It is a multi-dimensional agile waveform parameter that is resistant to interference. The degrees of freedom of the parameters of the preset multi-dimensional agile waveform are: is the degrees of freedom of the interference signal parameters.

[0019] In the above-mentioned multi-dimensional agile radar anti-interference waveform design method, the multi-dimensional agile radar anti-interference waveform is obtained by the following formula:

[0020]

[0021] in, is the multi-dimensional agile waveform parameter vector, is the multi-dimensional agile waveform parameter that can resist interference, R<T,G> is the generalized distance, T is the target echo factor, and G is the interference signal factor.

[0022] In the above-mentioned multi-dimensional agile radar anti-interference waveform design method, a received signal is obtained by the following formula:

[0023] r(t,f,s,p)=T(t,f,s,p)+G(t,f,s,p);

[0024] Among them, r(t,f,s,p) is the primary received signal, G(t,f,s,p) is the interference signal, T(t,f,s,p) is the target echo, and t, f, s, and p represent time, frequency, space, and codeword variables, respectively.

[0025] A multi-dimensional agile radar anti-interference waveform design system comprises: a first module, used for separating a target echo and an interference signal from a primary received signal, and estimating interference signal parameters from the interference signal; a second module, used for designing a generalized distance according to the interference signal parameters; a third module, used for obtaining the degrees of freedom of the interference signal parameters, and obtaining interference-resistant multi-dimensional agile waveform parameters according to the degrees of freedom of the interference signal parameters and the preset degrees of freedom of the multi-dimensional agile waveform parameters; and a fourth module, used for obtaining the multi-dimensional agile radar anti-interference waveform with the goal of maximizing the generalized distance and the interference-resistant multi-dimensional agile waveform parameters as constraints.

[0026] An electronic device comprises: a memory for storing computer-readable instructions; and a processor for running the computer-readable instructions to execute a multi-dimensional agile radar anti-interference waveform design method.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention solves the problem that traditional frequency-agile waveforms cannot resist new types of deceptive forwarding interference such as intermittent sampling interference. The method proposed in the present invention can separate the target echo and the interference signal and estimate the interference waveform parameters. Further, through multiple games, the freedom of the jammer waveform parameters can be confirmed to achieve complete resistance to forwarding deceptive interference, which is highly innovative and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0030] Figure 1 is a flow chart of a multi-dimensional agile radar anti-interference waveform design method provided by an embodiment of the present invention;

[0031] Figure 2 is a geometrical schematic diagram of a multi-dimensional agile waveform provided by an embodiment of the present invention;

[0032] Figure 3 It is a schematic diagram of the value range of the multi-dimensional agile waveform parameter that is resistant to interference provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0034] Figure 1 It is a flow chart of a multi-dimensional agile radar anti-interference waveform design method provided by an embodiment of the present invention.

[0035] like Figure 1 As shown, the multi-dimensional agile radar anti-interference waveform design method includes the following steps:

[0036] Step S10: separating the target echo and the interference signal from the primary received signal, and estimating interference signal parameters from the interference signal;

[0037] Step S20: designing a generalized distance according to interference signal parameters;

[0038] Step S30: repeating step S10 to obtain the degrees of freedom of the interference signal parameters, and obtaining the multidimensional agile waveform parameters that can resist interference according to the degrees of freedom of the interference signal parameters and the preset degrees of freedom of the multidimensional agile waveform parameters;

[0039] Step S40: Taking maximizing the generalized distance as the goal and taking the anti-interference multi-dimensional agile waveform parameters as the constraints, a multi-dimensional agile radar anti-interference waveform is obtained.

[0040] The method of separating a target echo and an interference signal from a received signal comprises the following steps: performing whitening processing on a received signal to obtain a whitened signal; estimating a fourth-order cumulant matrix of the whitened signal, and solving an unmixing matrix by joint diagonalization; multiplying the unmixing matrix and the whitened signal to extract a source signal component from the received signal; performing matched filtering on the source signal component and the agile frequency waveform transmitted this time, and the source signal component with a peak output is the target echo, and the interference signal is obtained by subtracting the target echo from the received signal.

[0041] The received signal is obtained by the following formula:

[0042] r(t,f,s,p)=T(t,f,s,p)+G(t,f,s,p);

[0043] Among them, r(t,f,s,p) is the primary received signal, G(t,f,s,p) is the interference signal, T(t,f,s,p) is the target echo, and t, f, s, and p represent time, frequency, space, and codeword variables, respectively.

[0044] The interference signal parameters are obtained by the following formula:

[0045]

[0046] in, is the interference signal parameter, G(t,f,s,p) is the interference signal, L{} is the likelihood function, is the interference parameter vector, t, f, s, p represent time, frequency, space and codeword variables respectively.

[0047] The generalized distance is obtained by the following formula:

[0048]

[0049] Among them, R<T,G> is the generalized distance, t, f, s, p represent time, frequency, space and codeword variables respectively, Θ T , Θ S , Θ F , Θ Pare the time interval, space interval, frequency interval, and code interval of the waveform respectively, I(·) is the indicative function, G(t,f,s,p) is the interference signal, T is the target echo factor, G is the interference signal factor, and T * (t,f,s,p) is the complex conjugate of T(t,f,s,p).

[0050] The degrees of freedom of the interference signal parameters are obtained by the following formula:

[0051]

[0052] in, is the degrees of freedom of the interference signal parameters, is the first interference signal parameter, is the second interference signal parameter, The Nth interference signal parameter, where N is the total number of confrontations.

[0053] The parameters of the multi-dimensional agile waveform that is resistant to interference are obtained by the following formula:

[0054]

[0055] in, It is a multi-dimensional agile waveform parameter that is resistant to interference. The degrees of freedom of the parameters of the preset multi-dimensional agile waveform are: is the degrees of freedom of the interference signal parameters.

[0056] The multi-dimensional agile radar anti-interference waveform is obtained by the following formula:

[0057]

[0058] in, is the multi-dimensional agile waveform parameter vector, is the multi-dimensional agile waveform parameter that can resist interference, R<T,G> is the generalized distance, T is the target echo factor, and G is the interference signal factor.

[0059] This embodiment first separates the target echo and the interference signal for a received echo based on a blind signal separation method, and estimates the interference signal parameters based on the maximum likelihood method; then defines the generalized distance based on the inner product between the target echo and the interference signal, and designs a multidimensional agile waveform that can resist this interference with the goal of maximizing the generalized distance; finally, through multiple rounds of competition with the interference signal, iteratively identifies the waveform parameter freedom of the jammer, and when the multidimensional agile waveform parameter freedom is greater than the interference waveform parameter freedom, a multidimensional agile transmission waveform can be designed outside the jammer waveform parameter freedom and within our waveform parameter freedom to achieve anti-interference.

[0060] Specifically, the method comprises the following steps:

[0061] Step 1: Separate the target echo and interference signal and estimate the interference signal parameters.

[0062] Separating a target echo and an interference signal from a primary received signal, and estimating interference signal parameters from the interference signal, specifically includes the following steps:

[0063] (11) Separate the target echo and interference signal based on the blind signal separation method.

[0064] Assume that the radar receiving signal is:

[0065] r(t,f,s,p)=T(t,f,s,p)+G(t,f,s,p) (1)

[0066] Where t, f, s, and p represent time, frequency, space, and codeword variables, respectively; T represents the target echo; and G represents the interference signal.

[0067] First, the received signal is whitened to reduce the signal dimension; then the fourth-order cumulant matrix of the whitened signal is estimated, and the unmixing matrix is ​​solved by joint diagonalization; then the unmixing matrix and the whitened signal are multiplied to extract the independent source signal components in the received signal; finally, the extracted source signal components and the agile frequency waveform transmitted this time are matched filtered, and the source signal component with a peak output is the target echo. Subtracting the target echo from the received signal can obtain the interference signal received this time.

[0068] In the specific implementation, in order to increase the accuracy of separation, the classification of interference can be identified by a trained convolutional neural network before whitening. Since the value ranges of various interference parameters are known, the accuracy of the estimation result in step (2) can be judged accordingly.

[0069] (12) Estimate the interference signal parameter value based on the maximum likelihood method.

[0070] The maximum likelihood method is used to estimate the parameter value of the interference signal from the separated interference signal:

[0071]

[0072] in is the interference parameter vector composed of t, f, s, p, and L is the likelihood function.

[0073] In specific implementation, the probability density function of the interference signal parameters can be made to obey a high-dimensional Gaussian function, and estimation is performed on this basis.

[0074] Step 2: Design generalized distance.

[0075] Construct a generalized distance in the time, frequency, space, and code dimensions, select the waveform parameter with the largest generalized distance with the interference signal waveform parameter within the freedom of our waveform parameters, and design the next transmission signal accordingly, specifically including the following steps:

[0076] The generalized distance is defined by the inner product between the target echo and the interference signal.

[0077] The generalized distance expression is defined as follows:

[0078]

[0079] where Θ T , Θ S , Θ F , Θ P are the time, space, frequency and code intervals of the waveform respectively. I(·) is an indicative function, which indicates the correspondence between the occurrence of time and the two functions of 0 and 1. The physical meaning of the waveform design function established based on this is to avoid the overlap of the interference waveform and the target echo as much as possible.

[0080] With the goal of maximizing the generalized distance, the next pulse multi-dimensional agile waveform is designed.

[0081] With the goal of maximizing the generalized distance and the parameter freedom as the constraint, we construct a multi-dimensional agile waveform constraint optimization problem, and use the optimization algorithm to solve the waveform parameters for the waveform design of the next pulse. The designed waveform optimization problem is as follows:

[0082]

[0083] in is a multi-dimensional agile waveform parameter vector composed of t, f, s, and p. Represents the degrees of freedom of our waveform parameters.

[0084] The optimization method is used to solve the above formula to obtain the transmission waveform parameters that can resist the current interference signal. Assuming that the next interference form is the same as this time, the next pulse signal waveform can be designed based on this.

[0085] In specific implementation, simulated annealing, genetic algorithm, particle swarm algorithm, Newton iteration algorithm, convex optimization algorithm, etc. can be used to solve equation (4) to obtain the multidimensional agile waveform parameters that can resist the current interference. Assuming that the next interference and the current interference parameters are close, the multidimensional agile waveform that can resist the current interference is likely to resist the next interference. Therefore, the next pulse transmission can resist the multidimensional agile waveform of the current interference. The form of the multidimensional agile waveform is shown in Figure 2 shown.

[0086] Step 3: Estimate the range of jammer waveform parameter values ​​based on multiple received signals, confirm the values ​​of multi-dimensional agile waveform parameters that can resist interference, and design the waveform based on the anti-interference parameters.

[0087] Assuming that the degree of freedom of my multi-dimensional agile waveform parameters is greater than the degree of freedom of the jammer waveform parameters, first estimate the jammer waveform parameter value range, then the multi-dimensional agile waveform parameter values ​​outside the jammer waveform parameter value range in my multi-dimensional agile waveform parameter value range are the anti-interference multi-dimensional agile waveform parameter values. Specifically, the following steps are included:

[0088] (31) Estimate the range of jammer waveform parameters based on multiple received signals.

[0089] Repeat step 2, and the interference parameter vector obtained by the Nth adversarial estimation is Assume that after N confrontations, the distribution area of ​​the interference parameters in time, frequency, space, and code dimensions does not change, that is, the degree of freedom of the interference waveform parameters is confirmed to be

[0090] (32) Confirm the range of values ​​of the multi-dimensional agile waveform parameters that are resistant to interference.

[0091] Since the degrees of freedom of the multidimensional agile waveform parameters are The degrees of freedom of the interference waveform parameters are Then, within the value range of the multi-dimensional agile waveform parameters, the value range outside the jammer waveform parameter range is the value range of the multi-dimensional agile waveform parameters that can resist interference, which can be expressed as:

[0092]

[0093] (33) Design a waveform based on the confirmed anti-interference parameters.

[0094]

[0095] In specific implementation, in order to achieve anti-deceptive interference, the degree of freedom of the multi-dimensional agile waveform parameters must be much greater than the degree of freedom of the interference waveform parameters. For example, the frequency of the multi-dimensional agile waveform needs to cover the C-Ka band, the antenna works for about half an hour each time, the antenna beam scanning angle must cover 4π space, and the code type can achieve pulse orthogonality within half an hour. The range of values ​​of the multi-dimensional agile waveform parameters that can resist interference is as follows: Figure 3 shown.

[0096] The present embodiment also provides a multi-dimensional agile radar anti-interference waveform design system, which includes: a first module, used to separate the target echo and the interference signal from a primary received signal, and estimate the interference signal parameters from the interference signal; a second module, used to design a generalized distance according to the interference signal parameters; a third module, used to obtain the degrees of freedom of the interference signal parameters, and obtain the interference-resistant multi-dimensional agile waveform parameters according to the degrees of freedom of the interference signal parameters and the preset degrees of freedom of the multi-dimensional agile waveform parameters; a fourth module, used to obtain the multi-dimensional agile radar anti-interference waveform with the goal of maximizing the generalized distance and the interference-resistant multi-dimensional agile waveform parameters as constraints.

[0097] This embodiment also provides an electronic device, including: a memory: used to store computer-readable instructions; and a processor: used to run the computer-readable instructions to execute the multi-dimensional agile radar anti-interference waveform design method.

[0098] This embodiment reduces the probability of being interfered by multi-dimensional rapid agility. In addition, through multiple games, the waveform parameter freedom of the jammer is iteratively identified, and based on this, a multi-dimensional agile transmission waveform is designed outside the waveform parameter freedom of the jammer and within the waveform parameter freedom of our side, thereby achieving comprehensive anti-interference.

[0099] This embodiment solves the problem that traditional frequency-agile waveforms cannot resist new types of deceptive forwarding interference such as intermittent sampling interference. The method proposed in the present invention can separate the target echo and the interference signal and estimate the interference waveform parameters. Further, through multiple games, the freedom of the jammer waveform parameters can be confirmed, and the forwarding deceptive interference can be completely resisted, which is highly innovative and practical.

[0100] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A multi-dimensional agile radar anti-interference waveform design method, characterized in that include: Step S10: separating the target echo and the interference signal from the primary received signal, and estimating interference signal parameters from the interference signal; Step S20: designing a generalized distance according to interference signal parameters; Step S30: repeating step S10 to obtain the degrees of freedom of the interference signal parameters, and obtaining the multidimensional agile waveform parameters that can resist interference according to the degrees of freedom of the interference signal parameters and the preset degrees of freedom of the multidimensional agile waveform parameters; Step S40: Taking maximizing the generalized distance as the goal and taking the anti-interference multi-dimensional agile waveform parameters as the constraints, a multi-dimensional agile radar anti-interference waveform is obtained.

2. The multi-dimensional agile radar anti-interference waveform design method according to claim 1, characterized in that: Separating the target echo and the interference signal from a received signal includes the following steps: Performing whitening processing on a received signal to obtain a whitened signal; Estimate the fourth-order cumulant matrix of the whitened signal and solve the unmixing matrix using joint diagonalization; Multiply the unmixing matrix and the whitened signal to extract the source signal component in the received signal; The source signal component and the frequency-agile waveform transmitted this time are matched and filtered, and the source signal component with a peak output is the target echo. The target echo is subtracted from the received signal to obtain the interference signal.

3. The multi-dimensional agile radar anti-interference waveform design method according to claim 1, characterized in that: The interference signal parameters are obtained by the following formula: in, is the interference signal parameter, G(t,f,s,p) is the interference signal, L{} is the likelihood function, is the interference parameter vector, t, f, s, p represent time, frequency, space and codeword variables respectively.

4. The multi-dimensional agile radar anti-interference waveform design method according to claim 1, characterized in that: The generalized distance is obtained by the following formula: Among them, R<T,G> is the generalized distance, t, f, s, p represent time, frequency, space and codeword variables respectively, Θ T , Θ S , Θ F , Θ P are the time interval, space interval, frequency interval, and code interval of the waveform respectively, I(·) is the indicative function, G(t,f,s,p) is the interference signal, T is the target echo factor, G is the interference signal factor, and T * (t,f,s,p) is the complex conjugate of T(t,f,s,p).

5. The multi-dimensional agile radar anti-interference waveform design method according to claim 1, characterized in that: The degrees of freedom of the interference signal parameters are obtained by the following formula: in, is the degrees of freedom of the interference signal parameters, is the first interference signal parameter, is the second interference signal parameter, The Nth interference signal parameter, where N is the total number of confrontations.

6. The multi-dimensional agile radar anti-interference waveform design method according to claim 1, characterized in that: The parameters of the multi-dimensional agile waveform that is resistant to interference are obtained by the following formula: in, It is a multi-dimensional agile waveform parameter that is resistant to interference. The degrees of freedom of the parameters of the preset multi-dimensional agile waveform are: is the degrees of freedom of the interference signal parameters.

7. The multi-dimensional agile radar anti-interference waveform design method according to claim 1, characterized in that: The multi-dimensional agile radar anti-interference waveform is obtained by the following formula: in, is the multi-dimensional agile waveform parameter vector, is the multi-dimensional agile waveform parameter that can resist interference, R<T,G> is the generalized distance, T is the target echo factor, and G is the interference signal factor.

8. The multi-dimensional agile radar anti-interference waveform design method according to claim 1 or 2, characterized in that: The received signal is obtained by the following formula: r(t,f,s,p)=T(t,f,s,p)+G(t,f,s,p); Among them, r(t,f,s,p) is the primary received signal, G(t,f,s,p) is the interference signal, T(t,f,s,p) is the target echo, and t, f, s, and p represent time, frequency, space, and codeword variables, respectively.

9. A multi-dimensional agile radar anti-interference waveform design system, characterized in that include: The first module is used to separate the target echo and the interference signal from the primary received signal, and estimate the interference signal parameters from the interference signal; The second module is used to design the generalized distance according to the interference signal parameters; The third module is used to obtain the degrees of freedom of the interference signal parameters, and obtain the multi-dimensional agile waveform parameters that can resist interference according to the degrees of freedom of the interference signal parameters and the preset degrees of freedom of the multi-dimensional agile waveform parameters; The fourth module is used to obtain a multi-dimensional agile radar anti-interference waveform with the goal of maximizing the generalized distance and the anti-interference multi-dimensional agile waveform parameters as constraints.

10. An electronic device, characterized in that: include: Memory: used to store computer-readable instructions; and Processor: used to run the computer-readable instructions to perform the method according to any one of claims 1 to 8.

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