Cognitive anti-interference method and device for vehicle-mounted FMCW radar

Abstract

The invention discloses a vehicle-mounted FMCW radar cognitive anti-interference method and device. The method comprises the following steps: acquiring an interference signal received by a target vehicle-mounted FMCW radar; performing frequency modulation slope estimation on the interference signal by using a fractional order Fourier transform algorithm to obtain an interference frequency modulation slope of the interference signal; based on a preset frequency modulation slope construction function and the interference frequency modulation slope, determining a frequency modulation slope of a target emission signal of the target vehicle-mounted FMCW radar; and performing interference suppression on an initial echo signal received by a pre-acquired target vehicle-mounted FMCW radar based on a target interference signal constructed on the basis of the interference frequency modulation slope to obtain a target echo signal. The method is used for effectively suppressing coherent interference and incoherent interference in a dense traffic scene. Fractional order Fourier transform is adopted to identify coherent interference and estimate the Chirp frequency modulation slope of incoherent interference, and the problems that in the prior art, vehicle-mounted radar mutual interference suppression is insufficient, especially coherent interference and long-duration incoherent interference suppression is insufficient, and the suppression effect robustness is poor are solved.

Description

Technical Field

[0001] This invention belongs to the field of radar signal processing technology, and particularly relates to a cognitive anti-interference method and device for vehicle-mounted FMCW radar. Background Technology

[0002] With the rapid development of advanced driver assistance systems and autonomous driving technologies, millimeter-wave radar has become an indispensable sensor due to its all-weather, all-day capability. FMCW (Frequency-Modulated Continuous Wave) signals are widely used in vehicle and traffic radars due to their ease of implementation, high range resolution, and low signal processing complexity. However, with the surge in the number of deployed radars, inter-radar interference has become a serious problem. Inter-radar interference can be divided into incoherent and coherent interference. Incoherent interference occurs when the interfering radar uses different parameters than the victim radar. This interference manifests as noise, raising the noise floor and reducing detection performance. Based on the duration of incoherent interference, it can be further divided into long-duration and short-duration incoherent interference. Coherent interference occurs when two radars use the same parameters. Although coherent interference occurs less frequently than incoherent interference, it is more harmful because it generates false targets that are very similar to real targets, making them difficult to suppress directly.

[0003] Existing technologies primarily focus on methods for suppressing short-duration incoherent interference. Incoherent interference suppression techniques can be categorized into filter-based methods, time-frequency domain methods, and sparse recovery techniques. Filter-based methods, such as adaptive noise cancellation and double recursive least squares filtering, utilize spectral correlation to suppress interference. Time-frequency domain methods separate targets from interference by leveraging different time and spectral characteristics; for example, time-frequency analysis based on short-time Fourier transform is used to identify and suppress interference junctions, such as the CFAR-Burg method based on the Burg algorithm for constant false alarm rate detection. Sparse recovery methods further utilize the sparsity of interference, such as low-rank Hankel matrix factorization and the iterative soft thresholding algorithm ISTA. Strategies for suppressing coherent interference can be broadly divided into radar-communication joint methods and waveform modification techniques. Radar-communication joint methods, such as cooperative waveform design and RadChat radar-communication fusion technology, improve the anti-interference capability of vehicle-mounted radars through inter-radar cooperation. Waveform modification techniques, such as phase coding methods and random frequency hopping schemes, mitigate or avoid interference by using group delay filters to align beat frequencies.

[0004] However, among existing methods for suppressing short-duration incoherent interference, filter-based methods, while relatively simple to implement, suffer from poor performance, often leaving a significant amount of residual interference unsuppressed. Time-frequency analysis-based methods are highly sensitive to detector parameters and struggle to handle complex interference scenarios. Coefficient recovery-based algorithms offer good suppression of short-duration incoherent interference, but their performance significantly degrades when suppressing long-duration incoherent interference. For coherent interference suppression techniques, such as radar-communication joint methods, pre-modulation and additional hardware are required, substantially increasing system costs. Waveform modification techniques like random phase modulation increase noise in the received signal to some extent, and the addition of group filters further increases hardware costs. Random frequency hopping cuts through the radar's available spectrum resources, reducing usable bandwidth and range resolution. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a vehicle-mounted FMCW radar cognitive anti-interference method and device.

[0006] The technical problem to be solved by this invention is achieved through the following technical solution: In a first aspect, the present invention provides a cognitive anti-jamming method for vehicle-mounted FMCW radar, comprising: Acquire the interference signal received by the target vehicle's FMCW radar; the interference signal is generated by an interference radar other than the target vehicle's FMCW radar. The frequency modulation slope of the interference signal is estimated by using the fractional Fourier transform algorithm, and the interference frequency modulation slope of the interference signal is obtained. Based on the preset frequency modulation slope construction function and the interference frequency modulation slope, the frequency modulation slope of the target vehicle-mounted FMCW radar signal is determined; The target interference signal is constructed based on the interference frequency modulation slope. The interference is suppressed on the initial echo signal received by the target vehicle-mounted FMCW radar, which is obtained in advance, to obtain the target echo signal. The initial echo signal includes the target echo signal corresponding to the target transmitted signal and the interference signal.

[0007] Secondly, the present invention provides a vehicle-mounted FMCW radar cognitive anti-jamming device, comprising: The signal acquisition module is used to acquire the interference signal received by the target vehicle-mounted FMCW radar; the interference signal is generated by an interference radar other than the target vehicle-mounted FMCW radar. The frequency modulation slope estimation module is used to estimate the frequency modulation slope of the interference signal using the fractional Fourier transform algorithm, so as to obtain the interference frequency modulation slope of the interference signal. The transmit waveform adjustment module is used to determine the frequency modulation slope of the target transmitted signal of the target vehicle-mounted FMCW radar based on the preset frequency modulation slope construction function and the interference frequency modulation slope. The interference suppression module is used to suppress the interference signal of the target vehicle-mounted FMCW radar received by the target based on the interference frequency modulation slope, and obtain the target echo signal. The echo signal includes the target echo signal corresponding to the target transmitted signal and the interference signal.

[0008] This invention provides a cognitive anti-interference method and device for vehicle-mounted FMCW radar, used to effectively suppress coherent and incoherent interference in dense traffic scenarios. It employs fractional Fourier transform to identify coherent interference and estimate the Chirp modulation slope of incoherent interference. Furthermore, based on the interference modulation slope, it adjusts the modulation slope of the target transmitted signal from the vehicle-mounted FMCW radar, thereby avoiding coherent interference while minimizing available bandwidth loss. Finally, the target interference signal constructed based on the interference modulation slope is used to suppress the echo signal received by the target vehicle-mounted FMCW radar, mitigating long-duration incoherent interference. This solves the problems of insufficient mutual interference suppression, particularly coherent interference and long-duration incoherent interference suppression, and poor robustness of suppression effects in existing vehicle-mounted radar technologies, resulting in a significant improvement in interference suppression performance.

[0009] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0010] Figure 1 This is a schematic diagram illustrating an application scenario of a vehicle-mounted FMCW radar cognitive anti-interference method provided in an embodiment of the present invention; Figure 2 This is a flowchart illustrating a vehicle-mounted FMCW radar cognitive anti-interference method provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of transmission and reception before and after waveform modification in an embodiment of the present invention; Figure 4 This is a schematic diagram of coherent and incoherent interference after fractional Fourier transform and constant false alarm rate detection in an embodiment of the present invention. Figure 5 This is a schematic diagram of a simulation experiment according to an embodiment of the present invention; Figure 6 This is the time-frequency spectrum diagram of the transmitted waveform before modification in the simulation experiment of this embodiment of the invention; Figure 7 This is the time-spectrum diagram of the modified transmission waveform in the simulation experiment of this invention embodiment; Figure 8 This is the time-frequency spectrum diagram after interference suppression in the simulation experiment of this invention embodiment; Figure 9 This is a comparison chart of the distance spectrum of simulation results in the simulation experiment of this invention embodiment; Figure 10 This is a structural block diagram of a vehicle-mounted FMCW radar cognitive anti-jamming device according to an embodiment of the present invention. Detailed Implementation

[0011] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0012] Before describing a vehicle-mounted FMCW radar cognitive anti-interference method according to an embodiment of the present invention, the application scenario of the embodiment of the present invention will be briefly described to facilitate understanding.

[0013] like Figure 1 As shown, considering that both the jamming radar and the target vehicle-mounted FMCW radar (i.e., the victim radar) use FMCW signals (Frequency-Modulated Continuous Wave), an interference model in a traffic scenario is established.

[0014] The transmitted signal with normalized amplitude from the target vehicle-mounted FMCW radar can be expressed as:

[0015] in, This indicates the transmission signal of the target vehicle's FMCW radar. It is the carrier frequency. It is the frequency modulation slope of the target vehicle's FMCW radar. It's bandwidth. This refers to the frequency modulation duration. The received echo signal, after mixing and low-pass filtering, can be written as:

[0016] in, This indicates the received echo signal. It is a low-pass filter operator. and They are from the target to be detected Target signals and jamming radar Interference signals, and They are the first The target signal and the first One interference signal, To transmit signals conjugate, and These are the number of target signals and interference signals, respectively.

[0017] Based on this, embodiments of the present invention provide a cognitive anti-jamming method for vehicle-mounted FMCW radar. See also Figure 2The method includes the following steps: S10. Acquire the interference signal received by the target vehicle's FMCW radar.

[0018] The jamming signal is generated by a jamming radar other than the target vehicle's FMCW radar.

[0019] Optionally, step S10 may specifically include: obtaining interference signals by inserting a silent chirp between two adjacent frames of transmitted signals sent by the target vehicle-mounted FMCW radar.

[0020] For example, by inserting a silent chirp at the end of the previous frame of transmitted signal between two adjacent frames of transmitted signal sent by the target vehicle-mounted FMCW radar, the interference signal is received. No transmitted signal is sent within the silent chirp, and only the echo signal is received. Therefore, the obtained echo signal does not have a part originating from the target to be detected, but only the interference signal exists.

[0021] A silent chirp (also known as a non-transmit chirp or inactive chirp) is a special time period in the FMCW radar frame structure. It refers to the time interval during which no radio frequency signals are actively transmitted, or the inactive chirp portion that does not perform signal sampling / processing, inserted into the regular transmit chirp sequence. It alternates with the regular transmit chirp, together forming a complete radar observation frame.

[0022] like Figure 3 As shown, the interference signal The specific mathematical expression can be written as:

[0023] in,

[0024]

[0025] In the formula, It is the first The frequency modulation slope of the interference signal, It is the relative time delay between the interference signal and the mixing signal. It is the amplitude of the interference signal. Represents a time variable.

[0026] S20. The frequency modulation slope of the interference signal is estimated by using the fractional Fourier transform algorithm to obtain the interference frequency modulation slope of the interference signal.

[0027] Optionally, step S20 may specifically include: S201. Perform a fractional Fourier transform on the interference signal to obtain the transform result corresponding to each order.

[0028] Optionally, the transformation result corresponding to each order is represented as:

[0029] in, This represents the transformation result corresponding to each order. The kernel function represents the fractional Fourier transform. It is a fractional frequency variable. Indicates the first One interference signal, Represents a time variable. Indicates the order.

[0030] For example, the kernel function is represented as:

[0031] in, Represents the rotation angle in the time-frequency plane ( ).

[0032] S202. Calculate the frequency domain energy peak for the transformation result corresponding to each order, and construct the order versus peak energy curve.

[0033] Optionally, the order versus peak energy curve is represented as:

[0034] in, This represents the order and peak energy curve.

[0035] S203. Perform constant false alarm rate detection on the order and peak energy curve to obtain the target order.

[0036] For example, refer to Figure 4 The target order was obtained by performing constant false alarm rate (CFAR) detection on the order and peak energy curves. .

[0037] S204. The interference frequency modulation slope of the interference signal is calculated based on the target order.

[0038] Optionally, the interference frequency modulation slope is expressed as:

[0039] in, Indicates the interference frequency modulation slope. Indicates the order of the objective. This indicates the frequency modulation slope of the target vehicle-mounted FMCW radar.

[0040] S30. Based on the preset frequency modulation slope construction function and the interference frequency modulation slope, determine the frequency modulation slope of the target vehicle-mounted FMCW radar's target transmitted signal.

[0041] For example, to balance the sparsity of interference in the time domain and the efficiency of spectrum utilization, a preset chirp rate construction function is used to determine the chirp rate of the target transmitted signal of the target vehicle-mounted FMCW radar, i.e., to adjust the waveform of the transmitted signal of the target vehicle-mounted FMCW radar. In scenarios where coherent and incoherent interference coexist, the adjustment of the chirp rate cannot be arbitrary. Vehicle-mounted radar systems are typically limited by the available bandwidth, which restricts the range of selectable chirp rates.

[0042] Optionally, a preset frequency modulation slope construction function is defined as follows:

[0043] in, This represents the frequency modulation slope of the target's transmitted signal. This indicates the selected frequency modulation slope parameter. Indicates the interference frequency modulation slope. Indicates the maximum permissible frequency modulation slope. This indicates the bandwidth of the low-pass filter. Indicates the duration of frequency modulation. Indicates hyperparameters, This indicates the number of interfering signals.

[0044] For example, the maximum permissible frequency modulation slope Represented as:

[0045] in, This indicates the maximum available bandwidth.

[0046] Subsequently, the target vehicle-mounted FMCW radar transmits the target's transmitted signal and receives the echo signal, performing digital sampling to obtain the initial echo signal. It can be expressed as:

[0047] in, , , and These represent the initial echo signal, the target echo signal, the interference signal, and the noise, respectively.

[0048] S40. Based on the interference frequency modulation slope, the target interference signal is constructed to suppress the initial echo signal received by the target vehicle-mounted FMCW radar, thereby obtaining the target echo signal.

[0049] The initial echo signal includes the target echo signal corresponding to the target's transmitted signal and the interference signal.

[0050] For example, the target interference signal constructed based on the interference frequency modulation slope is represented as:

[0051] in, Indicates target interference signal, This represents the low-pass filter operator. Indicates the interference frequency modulation slope. This indicates the frequency modulation slope of the target vehicle-mounted FMCW radar. Indicates the sampling point index. This indicates the sampling rate.

[0052] Optionally, step S40 may specifically include: using an iterative projection algorithm, using a target interference signal constructed based on the interference frequency modulation slope to suppress the interference of the initial echo signal received by the pre-acquired target vehicle-mounted FMCW radar, thereby obtaining the target echo signal.

[0053] Furthermore, the specific steps include: S401. Based on the target interference signal constructed from the interference frequency modulation slope and the updated echo signal of the current iteration, determine the normalized correlation coefficient; and determine the time delay parameter corresponding to the largest normalized correlation coefficient.

[0054] Among them, the update echo signal of the initial iteration is the initial echo signal.

[0055] For example, the update echo signal for the initial iteration is set. Calculate the normalized correlation coefficient :

[0056] in, Indicates target interference signal, Indicates the current iteration number. This represents linear convolution. The time delay parameter corresponding to the largest normalized correlation coefficient , is represented as:

[0057] in, This represents the time delay parameter corresponding to the normalized correlation coefficient.

[0058] S402. Based on the time delay parameter and the target interference signal, construct the reconstructed interference signal for the current iteration.

[0059] For example, reconstructing the interference signal Represented as:

[0060] in, This indicates the total number of sampling points.

[0061] S403. Project the reconstructed interference signal onto the update echo signal of the current iteration to obtain the update coefficients of the current iteration.

[0062] For example, the update coefficients of the current iteration , is represented as:

[0063] S404. Based on the update coefficients and reconstructed interference signal of the current iteration, the update echo signal of the current iteration is suppressed to obtain the update echo signal of the next iteration; until the preset iteration stop condition is reached, the target echo signal is obtained.

[0064] For example, the updated echo signal in the next iteration , is represented as:

[0065] The preset iteration stop condition can be the preset maximum number of iterations.

[0066] This embodiment provides a cognitive anti-jamming method for vehicle-mounted FMCW radar, used to effectively suppress coherent and incoherent interference in dense traffic scenarios. It employs fractional Fourier transform to identify coherent interference and estimate the Chirp modulation slope of incoherent interference. Furthermore, an adaptive waveform adjustment strategy is used to adjust the modulation slope of the target transmitted signal from the vehicle-mounted FMCW radar, thereby avoiding coherent interference while minimizing available bandwidth loss. Finally, an iterative projection algorithm is used for interference suppression, mitigating long-duration incoherent interference. This solves the problems of insufficient mutual interference suppression, particularly coherent interference and long-duration incoherent interference suppression, and poor robustness of suppression effects in existing vehicle-mounted radar technologies, resulting in a significant improvement in interference suppression performance.

[0067] The following simulation experiment further illustrates the vehicle-mounted FMCW radar cognitive anti-jamming method provided by this invention.

[0068] Experimental setup as follows Figure 5The traffic scenario shown is illustrated. In this scenario, three vehicles are located at distances of 50 m, 80 m, and 150 m, respectively. Target vehicle 1 and target vehicle 2 are equipped with two and three jamming radars, respectively. Their relative speeds to the victim radar are set to 10 m / s, -20 m / s, and -25 m / s, respectively, and the low-pass filter cutoff frequency is 10 MHz. The victim radar's frequency modulation slope is 6.00 MHz / µs, while the jamming radars' frequency modulation slopes are 4.80, 6.60, 4.20, 6.18, and 6.00 MHz / µs, respectively. This indicates that there is one coherent interference and four incoherent interferences in this scenario. The time-spectrum diagram of the received raw echo signal is shown below. Figure 6 As shown, the three weaker parallel lines represent the target's echo signal, the one stronger line represents the echo signal of coherent interference, and the four diagonal lines represent incoherent interference. The radar time-frequency spectrum of the initial echo signal received after modifying the transmitted signal waveform (i.e., transmitting the target's transmitted signal) is shown below. Figure 7 As shown, horizontal coherent interference is converted into incoherent interference. The time-spectrum diagram of the target echo signal obtained after passing through the interference suppression algorithm of this invention is shown below. Figure 8 As shown, the interference signal is well suppressed, and the method of the present invention effectively preserves the target signal.

[0069] like Figure 9 As shown, based on the comparison between the present invention and existing methods, the CFAR-Burg algorithm failed to remove all interference, the SPARKLE algorithm failed to recover the target signal, and the ISTA algorithm suppressed some interference but left residues. In contrast, the method of the present invention, due to its explicit modeling of long-duration incoherent interference, achieves a closest match to the reference signal in terms of amplitude (magnitude) and peak shape. This indicates that the method of the present invention has better robustness and accuracy under strong interference conditions.

[0070] On the other hand, embodiments of the present invention also provide a vehicle-mounted FMCW radar cognitive anti-jamming device, referring to... Figure 10 The device specifically includes: The signal acquisition module 201 is used to acquire the interference signal received by the target vehicle-mounted FMCW radar; the interference signal is generated by an interference radar other than the target vehicle-mounted FMCW radar. The frequency modulation slope estimation module 202 is used to estimate the frequency modulation slope of the interference signal using a fractional Fourier transform algorithm to obtain the interference frequency modulation slope of the interference signal. The transmit waveform adjustment module 203 is used to determine the frequency modulation slope of the target transmit signal of the target vehicle-mounted FMCW radar based on the preset frequency modulation slope construction function and the interference frequency modulation slope. The interference suppression module 204 is used to suppress the interference signal received by the target vehicle-mounted FMCW radar based on the target interference signal constructed based on the interference frequency modulation slope, and to obtain the target echo signal. The echo signal includes the target echo signal corresponding to the target transmitted signal and the interference signal.

[0071] For details regarding the device, please refer to the steps of the vehicle-mounted FMCW radar cognitive anti-jamming method provided in the first aspect; they will not be repeated here.

[0072] This embodiment provides a vehicle-mounted FMCW radar cognitive anti-jamming device for effectively suppressing coherent and incoherent interference in dense traffic scenarios. It employs fractional Fourier transform to identify coherent interference and estimate the Chirp modulation slope of incoherent interference. Furthermore, an adaptive waveform adjustment strategy is used to adjust the modulation slope of the target transmitted signal from the vehicle-mounted FMCW radar, thereby avoiding coherent interference while minimizing available bandwidth loss. Finally, an iterative projection algorithm is used for interference suppression, mitigating long-duration incoherent interference. This solves the problems of insufficient suppression of mutual interference between vehicle-mounted radars, especially coherent interference and long-duration incoherent interference, and poor robustness of the suppression effect, resulting in a significant improvement in interference suppression performance.

[0073] It should be noted that the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention.

[0074] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0075] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings and the disclosure in carrying out the claimed invention. In the description of the invention, the word "comprising" does not exclude other components or steps, "a" or "an" does not exclude a plurality, and "a plurality" means two or more, unless otherwise explicitly specified. Furthermore, while different embodiments may describe certain measures, this does not mean that these measures cannot be combined to produce good results.

[0076] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A cognitive anti-interference method for vehicle-mounted FMCW radar, characterized in that, include: Acquire the interference signal received by the target vehicle-mounted FMCW radar; the interference signal is generated by an interference radar other than the target vehicle-mounted FMCW radar; The frequency modulation slope of the interference signal is estimated by using a fractional Fourier transform algorithm to obtain the interference frequency modulation slope of the interference signal; Based on the preset frequency modulation slope construction function and the interference frequency modulation slope, the frequency modulation slope of the target transmitted signal of the target vehicle-mounted FMCW radar is determined; Based on the target interference signal constructed using the interference frequency modulation slope, interference suppression is performed on the initial echo signal received by the target vehicle-mounted FMCW radar, which was acquired in advance, to obtain the target echo signal. The initial echo signal includes the target echo signal corresponding to the target transmitted signal and the interference signal.

2. The vehicle-mounted FMCW radar cognitive anti-interference method according to claim 1, characterized in that, The step of estimating the frequency modulation slope of the interference signal using a fractional Fourier transform algorithm to obtain the interference frequency modulation slope of the interference signal includes: Perform a fractional Fourier transform on the interference signal to obtain the transform result corresponding to each order; Calculate the frequency domain energy peak for the transformation result corresponding to each order, and construct the order versus peak energy curve; The target order is obtained by performing constant false alarm rate detection on the order and peak energy curve. The interference frequency modulation slope of the interference signal is calculated based on the target order.

3. The vehicle-mounted FMCW radar cognitive anti-interference method according to claim 2, characterized in that, The transformation result corresponding to each order is expressed as follows: in, This represents the transformation result corresponding to each order. The kernel function represents the fractional Fourier transform. It is a fractional frequency variable. Indicates the first One interference signal, Represents a time variable. Indicates the order; The order and peak energy curve are expressed as follows: in, This represents the curve showing the order and peak energy. The interference frequency modulation slope is expressed as: in, Indicates the interference frequency modulation slope. Indicates the order of the objective. This indicates the frequency modulation slope of the target vehicle-mounted FMCW radar.

4. A vehicle-mounted FMCW radar cognitive anti-interference method according to any one of claims 1-3, characterized in that, The preset frequency modulation slope construction function is expressed as follows: in, This represents the frequency modulation slope of the target's transmitted signal. This indicates the selected frequency modulation slope parameter. Indicates the interference frequency modulation slope. Indicates the maximum permissible frequency modulation slope. This indicates the bandwidth of the low-pass filter. Indicates the duration of frequency modulation. Indicates hyperparameters, This indicates the number of interfering signals.

5. The vehicle-mounted FMCW radar cognitive anti-interference method according to claim 1, characterized in that, The target interference signal constructed based on the interference frequency modulation slope is used to suppress the initial echo signal received by the target vehicle-mounted FMCW radar, obtained in advance, to obtain the target echo signal, including: Using an iterative projection algorithm, the target interference signal constructed based on the interference frequency modulation slope is used to suppress the initial echo signal received by the target vehicle-mounted FMCW radar, which is obtained in advance, to obtain the target echo signal.

6. The vehicle-mounted FMCW radar cognitive anti-interference method according to claim 5, characterized in that, The method utilizes an iterative projection algorithm to suppress the initial echo signal received by the target vehicle-mounted FMCW radar based on the target interference signal constructed using the interference frequency modulation slope, thereby obtaining the target echo signal, including: Based on the target interference signal constructed from the interference frequency modulation slope and the updated echo signal of the current iteration, the normalized correlation coefficient is determined; and the time delay parameter corresponding to the largest normalized correlation coefficient is determined; wherein, the updated echo signal of the initial iteration is the initial echo signal; Based on the time delay parameter and the target interference signal, construct the reconstructed interference signal for the current iteration; The reconstructed interference signal is projected onto the updated echo signal of the current iteration to obtain the update coefficients of the current iteration; Based on the update coefficients and the reconstructed interference signal of the current iteration, interference suppression is performed on the update echo signal of the current iteration to obtain the update echo signal of the next iteration; until the preset iteration stop condition is reached, the target echo signal is obtained.

7. The vehicle-mounted FMCW radar cognitive anti-interference method according to claim 1, characterized in that, The acquisition of the interference signal received by the target vehicle's FMCW radar includes: The interference signal is obtained by inserting a silent chirp between two adjacent frames of transmitted signals sent by the target vehicle-mounted FMCW radar.

8. A vehicle-mounted FMCW radar cognitive anti-jamming device, characterized in that, include: The signal acquisition module is used to acquire the interference signals received by the target vehicle-mounted FMCW radar; The interference signal is generated by an interference radar other than the target vehicle's FMCW radar; The frequency modulation slope estimation module is used to estimate the frequency modulation slope of the interference signal using a fractional Fourier transform algorithm to obtain the interference frequency modulation slope of the interference signal. The transmit waveform adjustment module is used to determine the frequency modulation slope of the target transmit signal of the target vehicle-mounted FMCW radar based on a preset frequency modulation slope construction function and the interference frequency modulation slope. An interference suppression module is used to suppress the echo signal received by the target vehicle-mounted FMCW radar in advance by constructing a target interference signal based on the interference frequency modulation slope, thereby obtaining the target echo signal, wherein the echo signal includes the target echo signal corresponding to the target transmitted signal and the interference signal.

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