Sidelobe cancellation method and device, electronic equipment, medium and product
By combining the narrow pulse selection and side lobe cancellation methods of radar, effective acquisition and cancellation of low duty cycle interference signals is achieved, solving the problems of low acquisition probability and high resource requirements in traditional methods, and improving the cancellation efficiency of interference signals.
Patent Information
- Application Number
- CN202510594017.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-09
- Publication Date
- 2025-08-01
AI Technical Summary
In the prior art, the traditional sidelobe cancellation method has a low probability of acquisition of agile interference signal with a low duty cycle and high requirements for engineering applications, making it difficult to effectively realize interference signal cancellation.
Combining the narrow pulse selection and side lobe cancellation methods of the radar, the interference signal samples are obtained at the moment of narrow pulse selection, the secondary lobe cancellation vector is calculated, and signal processing is performed in the processing model to achieve accurate selection and cancellation of the interference signal.
Without selecting radar signals, accurately selecting interference samples to effectively eliminate interference signals, reduce the requirements for hardware and computing resources, and improve the acquisition probability and cancellation effect of interference signals.
Smart Images
Figure CN120405580A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of radar signal processing, and particularly relates to a sidelobe cancellation method, device, electronic device, medium and product. Background Art
[0002] Sidelobe cancellation (SLC), also known as secondary lobe cancellation, is one of the important sidelobe anti-jamming means of radar. The principle of sidelobe cancellation is to adaptively calculate the weighting coefficients of the auxiliary channel signals through the interference samples in the main and auxiliary channel signals, and achieve the purpose of sidelobe interference cancellation by subtracting the weighted sum of the auxiliary channel signals from the main channel.
[0003] The core of the sidelobe cancellation algorithm lies in calculating the weighting coefficients of the auxiliary channel. There are two key steps in the calculation process: one is to remove the target signal in the auxiliary channel, and the other is to collect the samples of the interference signal. The methods for removing the target signal include time-domain elimination method, blocking matrix method, generalized inner product method, etc. When the interference signal in the auxiliary channel is strong and the duty cycle is large, the target signal can also be not considered.
[0004] The traditional method for selecting interference samples is intermittent sampling method, which samples at the end of the radar transmission cycle. At this time, there is generally no radar echo signal, but this sampling method is generally only effective for the suppression interference that exists throughout the period. For the low-duty-cycle smart interference, the probability of collecting interference samples is significantly reduced. In order to improve the probability of collecting interference samples, theoretically, if the entire cycle signal is used to calculate the weighting coefficients, the interference samples will definitely be collected, and interference cancellation can be achieved. However, this will pose higher requirements on the radar's software and hardware acquisition, calculation and storage capabilities, and the cost of engineering application is relatively high.
[0005] In the related art, due to the intermittent sampling characteristics of the interference signal, there are certain technical challenges for sidelobe cancellation. Summary of the Invention
[0006] In view of the above problems, the present application provides a sidelobe cancellation method, device, electronic device, medium and product, which combines two anti-jamming means of narrow pulse selection and sidelobe cancellation of radar, selects interference samples for sidelobe cancellation, ensures that radar signals are not selected, and realizes the cancellation of interference signals in the direction where the interference is located.
[0007] In a first aspect, an embodiment of the present application provides a sidelobe cancellation method, including:
[0008] Select narrow pulses according to the main channel signal of the radar, and obtain interference signal samples corresponding to the auxiliary channel signal of the radar at the moment of the narrow pulse selection;
[0009] Calculate the sidelobe cancellation vector based on the main channel signal and the interference signal samples;
[0010] Input the main channel signal, the auxiliary channel signal, and the sidelobe cancellation vector into a pre-established processing model to obtain the radar echo signal after sidelobe cancellation.
[0011] In some embodiments, the expression of the processing model includes:
[0012]
[0013] where y(t) is the main channel signal, X is the signal vector of the auxiliary channel, and W opt is the sidelobe cancellation vector.
[0014] In some embodiments, the narrow pulse selection based on the main channel signal of the radar includes:
[0015] Perform envelope detection on the main channel signal to determine the pulse sequence;
[0016] Judge whether the pulse width of the pulse sequence exceeds the threshold;
[0017] If it is determined that the pulse sequence does not exceed the threshold, it is determined as an interfering narrow pulse and is selected in the auxiliary channel of the radar.
[0018] In some embodiments, the obtaining of the interference signal samples corresponding to the auxiliary channel signal of the radar at the time of the narrow pulse selection includes:
[0019] Select the signal vector of the auxiliary channel at the time of the narrow pulse selection;
[0020] Obtain the interference signal samples of the selected auxiliary channel.
[0021] In a second aspect, an embodiment of the present application provides a sidelobe cancellation method device, including:
[0022] An acquisition module, configured to perform narrow pulse selection according to the main channel signal of the radar and obtain interference signal samples corresponding to the auxiliary channel signal of the radar at the time of the narrow pulse selection;
[0023] A calculation module, configured to calculate the sidelobe cancellation vector based on the main channel signal and the interference signal samples;
[0024] A processing module, configured to input the main channel signal, the auxiliary channel signal, and the sidelobe cancellation vector into a pre-established processing model to obtain the radar echo signal after sidelobe cancellation.
[0025] In some embodiments, the device further includes:
[0026] A detection module, configured to perform envelope detection on the main channel signal to determine a pulse sequence;
[0027] A judgment module, configured to judge whether the pulse width of the pulse sequence exceeds a threshold;
[0028] A selection module, configured to determine it as an interference narrow pulse in the case that it is determined that the pulse sequence does not exceed the threshold, and perform selection in the auxiliary channel of the radar.
[0029] In some embodiments, the device further includes:
[0030] A screening module, configured to screen the signal vector of the auxiliary channel at the moment of narrow pulse selection;
[0031] A sub-acquisition module, configured to acquire the interference signal sample of the selected auxiliary channel.
[0032] In a third aspect, an embodiment of the present application provides an electronic device, including a memory and a processor, where a computer program that can run on the processor is stored on the memory, and when the computer program is executed by the processor, it implements a sidelobe cancellation method introduced in any implementation manner of the first aspect.
[0033] In a fourth aspect, an embodiment of the present application provides a computer storage medium, which stores one or more programs, and the one or more programs can be executed by the electronic device introduced in the third aspect to implement a sidelobe cancellation method introduced in any implementation manner of the first aspect.
[0034] In a fifth aspect, an embodiment of the present application provides a computer program product, including a computer program, and when the computer program is executed by a processor, it implements a sidelobe cancellation method introduced in any implementation manner of the first aspect.
[0035] A sidelobe cancellation method, device, electronic device, medium and product provided by an embodiment of the present application perform narrow pulse selection according to the main channel signal of the radar, acquire the interference signal sample corresponding to the auxiliary channel signal of the radar at the moment of narrow pulse selection, calculate the sidelobe cancellation vector based on the main channel signal and the interference signal sample, and input the main channel signal, the auxiliary channel signal and the sidelobe cancellation vector into a pre-established processing model to obtain the radar echo signal after sidelobe cancellation. It is possible to accurately select interference samples while ensuring that radar signals are not selected through narrow pulse selection, and cancel the interference signals in the direction where the interference is located through the selected interference samples.
[0036] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become easily understood through the following description. Brief Description of the Drawings
[0037] In the following, the present application will be described in more detail based on embodiments and with reference to the drawings.
[0038] Figure 1 Fig. shows a schematic flowchart of a sidelobe cancellation method proposed in an embodiment of the present application;
[0039] Figure 2 Fig. shows a schematic diagram of a specific implementation process of an exemplary sidelobe cancellation method proposed in an embodiment of the present application;
[0040] Figure 3 Fig. shows a schematic diagram of an exemplary application scenario proposed in an embodiment of the present application;
[0041] Figure 4 Fig. shows a schematic diagram of an exemplary target echo signal proposed in an embodiment of the present application;
[0042] Figure 5 Fig. shows a schematic diagram of the relative relationship between an exemplary interference signal and a radar signal proposed in an embodiment of the present application;
[0043] Figure 6 Fig. shows a schematic diagram of an exemplary main receiving channel signal proposed in an embodiment of the present application;
[0044] Figure 7 Fig. shows a schematic diagram of an exemplary auxiliary channel signal proposed in an embodiment of the present application;
[0045] Figure 8 Fig. shows a schematic diagram of an exemplary echo signal after beamforming proposed in an embodiment of the present application;
[0046] Figure 9 Fig. shows a schematic diagram of the envelope of an exemplary echo signal after beamforming proposed in an embodiment of the present application;
[0047] Figure 10 Fig. shows a schematic diagram of an exemplary interference sample obtained by narrow pulse selection in an auxiliary channel proposed in an embodiment of the present application;
[0048] Figure 11 Fig. shows a schematic diagram of an exemplary radar echo signal after sidelobe cancellation proposed in an embodiment of the present application;
[0049] Figure 12 Fig. shows a schematic diagram of the comparison of the antenna patterns before and after sidelobe cancellation proposed in an embodiment of the present application;
[0050] Figure 13Shows a structural block diagram of an exemplary sidelobe cancellation device proposed in an embodiment of the present application;
[0051] Figure 14 Shows a structural block diagram of an electronic device for performing a sidelobe cancellation method according to an embodiment of the present application;
[0052] Figure 15 Shows a computer-readable storage medium for storing or carrying out a sidelobe cancellation method according to an embodiment of the present application. Detailed implementation manners
[0053] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the embodiments and the accompanying drawings. The illustrative embodiments and descriptions thereof of the present invention are only used to explain the present invention and do not limit the present invention.
[0054] Analyzing the existing problems, for the intermittent sampling characteristics of the interference signal, the present application combines two anti-interference means of narrow pulse selection and sidelobe cancellation of the radar for the method of selecting interference samples for sidelobe cancellation.
[0055] The present application proposes a sidelobe cancellation method, device, electronic device, medium and product. By narrow pulse selection, while accurately selecting interference samples, it can ensure that radar signals are not selected. Through the selected interference samples, the interference signals in the direction of the interference are cancelled. Among them, a sidelobe cancellation method will be described in detail in the subsequent embodiments.
[0056] The following introduces the application scenarios of a sidelobe cancellation method provided in the embodiments of the present application:
[0057] Please refer to Figure 1 , Figure 1 which is a schematic flow diagram of a sidelobe cancellation method provided in the embodiments of the present application. In this embodiment, a sidelobe cancellation method can be applied to a sidelobe cancellation device 300 based on active detection at the sending end as shown in Figure 13 and an electronic device 200 as shown in Figure 14 . Among them, the electronic device can include one or more. Information can be transmitted between multiple electronic devices in a wireless and / or wired manner. Multiple electronic devices can cooperate to complete a sidelobe cancellation method. Exemplarily, the electronic device can include a computer, a mobile terminal, a communication device, etc. The present application does not limit it. The following elaborates in detail on the process shown in Figure 1 . This sidelobe cancellation method can include S110 to S130.
[0058] S110: performing narrow pulse selection according to the main channel signal of the radar, and obtaining an interference signal sample corresponding to the auxiliary channel signal of the radar at the moment of narrow pulse selection.
[0059] S120: Calculate a sidelobe cancellation vector based on the main channel signal and the interference signal samples.
[0060] S130: Inputting the main channel signal, the auxiliary channel signal and the sidelobe cancellation vector into a pre-established processing model to obtain a radar echo signal after sidelobe cancellation.
[0061] In the embodiments of this application, refer to Figure 2 The schematic diagram of an exemplary implementation process of the sidelobe cancellation method is shown. By selecting narrow pulses of the radar main channel signal y(t), the corresponding time signal is selected from the auxiliary channel signal vector X as the interference signal sample X′; the SLC optimal weight vector W is obtained by combining the selected auxiliary channel interference sample X′ with the main channel signal y(t). opt , through y(t), X, W opt , calculate the radar echo signal after sidelobe cancellation
[0062] See Figure 2 It can be seen that, in some embodiments, performing narrow pulse selection based on the main channel signal of the radar includes:
[0063] Perform envelope detection on the main channel signal to determine the pulse sequence;
[0064] Determine whether the pulse width of the pulse sequence exceeds the threshold;
[0065] When it is determined that the pulse sequence does not exceed the threshold, it is determined to be an interference narrow pulse and is selected in the auxiliary channel of the radar.
[0066] In some embodiments, obtaining an interference signal sample corresponding to an auxiliary channel signal of a radar at a time of narrow pulse selection includes:
[0067] Select the signal vector of the auxiliary channel at the moment of narrow pulse selection;
[0068] Obtain interference signal samples of the selected auxiliary channels.
[0069] In a specific embodiment:
[0070] See Figure 3The following diagram illustrates an exemplary application scenario. Assume that the scenario involves a radar, a detected target, and a jammer. The target is located 15 kilometers radially from the radar, and the jammer is 30 kilometers away. The target is located due north of the radar, and the jammer is located 20° east of north, as shown below. It should be noted that this scenario is for illustrative purposes only; the present invention can be applied to various sidelobe jamming scenarios.
[0071] The radar signal has a pulse width of T, a bandwidth of B, and a pulse repetition period of PRI. Here, it is assumed that T = 72 us, B = 5 MHz, and PRI = 500 us. The above parameters are for illustration only. The present invention can be applied to various radar waveforms.
[0072] Assume the radar receiving array is a one-dimensional 64-element linear array. The receiving channels have 60 main channels and 4 SLC auxiliary channels. In practical applications, the array form and number of elements are not restricted; the only requirement is to ensure that the number of SLC auxiliary channels is sufficient and not less than the number of interference sources. The elements are spaced evenly, at half a wavelength.
[0073] This method is applicable to radars of any operating frequency band. Here, it is assumed that the radar operating frequency is 3 GHz, the wavelength is 0.1 m, and the array spacing is 0.05 m.
[0074] The amplitude of the target echo signal of a single channel of the radar receiving antenna is normalized to 1, and the obtained signal is as follows: Figure 4 Schematic diagram of target echo signal shown.
[0075] Assume that the interference signal type is a combination of common intermittent sampling interference signal and noise interference, where the first interference signal from 205us to 277us is an intermittent sampling interference signal, and the second interference signal from 300us to 450us is a noise interference signal. The signal-to-interference ratio of a single channel of the radar receiving antenna is 40dB. If the interference signal is Figure 5 Schematic diagram of the relative relationship between the interference signal and the radar signal.
[0076] The echo signal received by the radar contains target signal, interference signal and noise at the same time. Assuming the signal-to-noise ratio is 10dB, the effect of the superposition of the three signals in all main receiving channels is as follows: Figure 6 The main receiving channel signal diagram shown in FIG. Figure 6 The signals of channels 1, 2, 59, and 60 are plotted as examples.
[0077] Among them, the effect of the superposition of the three signals in the 4 sidelobe cancellation auxiliary channels is as follows: Figure 7 The auxiliary channel signal diagram shown in the figure is assumed to be a signal vector X = [x1(t), x2(t), ..., x M (t)]T , M=4.
[0078] After beamforming the received signals of all main channels, the echo signals obtained are as follows: Figure 8 FIG. 1 is a schematic diagram of an echo signal after beamforming, where the signal is y(t).
[0079] The result of envelope detection on the echo signal after beamforming is as follows: Figure 9 The envelope of the echo signal after beamforming is shown in FIG. Envelope detection technology can be implemented by using low-pass filtering, Hilbert transform and other technical means, which will not be described in detail here.
[0080] After the echo passes through envelope detection, the following segmented pulses are obtained:
[0081] Pulse 1: 100us~168us, pulse width 68us; Pulse 2: 205us~210us, pulse width 5us; Pulse 3: 215us~220us, pulse width 5us; Pulse 4: 225us~230us, pulse width 5us; Pulse 5: 235us~2140us, pulse width 5us; Pulse 6: 245us~250us, pulse width 5us; Pulse 7: 255us~260us, pulse width 5us; Pulse 8: 265us~270us, pulse width 5us; Pulse 9: 275us~277us, pulse width 2us; Pulse 10: 300us~450us, pulse width 150us.
[0082] Given a radar signal pulse width of T, the threshold for narrow pulse width selection can be flexibly configured based on the actual interference signal received. Any pulse width less than the radar pulse width and greater than the maximum pulse width of the interference signal is acceptable. A typical configuration is to set it to a larger value less than the pulse width, such as 0.8 times the pulse width, which is 57.6µs in this implementation. Segmented pulse signals with pulse widths less than this threshold are selected, and interference samples for sidelobe cancellation are obtained from the signals of the four auxiliary channels according to their corresponding time indexes.
[0083] In this example, since the pulse widths of pulses 2 to 9 are less than the threshold, the corresponding signal samples will be selected as interference samples. Figure 10 The schematic diagram of interference samples obtained by selecting narrow pulses in the auxiliary channel shown in the figure is as follows. Assume that its signal vector is X′=[x1′(t),x2′(t),…,x′ M (t)] T , M=4.
[0084] Carry out sidelobe cancellation processing. Use the auxiliary channel signal X' after narrow pulse selection to calculate the autocorrelation matrix R of the signal in the auxiliary channel xx; Calculate the cross-correlation vector r of the main-channel signal y(t) and the auxiliary-channel signal X'. xy , then the optimal weight vector of the SLC is The output of the radar echo signal after sidelobe cancellation is: Where represents the conjugate transpose of the vector W opt . The output signal is as shown in the schematic diagram of the radar echo signal after sidelobe cancellation in Figure 11 . The interference signal has been cancelled, leaving only the radar echo.
[0085] Use W opt as the weighting coefficient of the auxiliary channel to calculate the array pattern after sidelobe cancellation processing.
[0086] Refer to Figure 12 for the schematic diagram of the comparison of the antenna patterns before and after sidelobe cancellation. Compared with before the cancellation processing, it can be found that there is an obvious notch at the azimuth (20°) where the interference is located, indicating that the interference energy has been cancelled.
[0087] Through the method adopted in the present invention, the narrow-pulse interference signal in the radar echo and other interference signals in the same direction can be cancelled, achieving a good anti-sidelobe interference effect.
[0088] Please refer to Figure 13 , Figure 13 which is the structural block diagram of a sidelobe cancellation device provided by this application. The sidelobe cancellation device 300 includes: an acquisition module 310, a calculation module 320, and a processing module 330, where:
[0089] The acquisition module 310 is used to select narrow pulses according to the main-channel signal of the radar and obtain the interference signal samples corresponding to the auxiliary-channel signal of the radar at the moment of narrow-pulse selection.
[0090] The calculation module 320 is used to calculate the sidelobe cancellation vector based on the main-channel signal and the interference signal samples.
[0091] The processing module 330 is used to input the main-channel signal, the auxiliary-channel signal, and the sidelobe cancellation vector into a pre-established processing model to obtain the radar echo signal after sidelobe cancellation.
[0092] In some embodiments, the sidelobe cancellation device 300 further includes:
[0093] A detection module, used to perform envelope detection on the main-channel signal to determine the pulse sequence;
[0094] A judgment module, used to judge whether the pulse width of the pulse sequence exceeds the threshold;
[0095] A selection module, configured to determine, when it is determined that the pulse sequence does not exceed the threshold, that it is an interfering narrow pulse and perform selection in the auxiliary channel of the radar.
[0096] In some embodiments, the sidelobe cancellation device 300 further includes:
[0097] A screening module, configured to screen the signal vector of the auxiliary channel at the moment of narrow pulse selection;
[0098] A sub-acquisition module, configured to acquire the interference signal samples of the selected auxiliary channel.
[0099] The device embodiments in this application may further include other modules, which specifically correspond to the content in the above method part.
[0100] It should be noted that the device embodiments in this application correspond to the foregoing method embodiments. The specific principles in the device embodiments can be referred to the content in the foregoing method embodiments and will not be elaborated here.
[0101] In several embodiments provided in this embodiment, the coupling between modules may be electrical, mechanical or other forms of coupling.
[0102] In addition, in each embodiment of the present invention, the functional modules may be integrated in a processing module, or each module may exist physically alone, or two or more modules may be integrated in one module. The above integrated modules may be implemented in the form of hardware or in the form of software functional modules.
[0103] Please refer to Figure 14 , Figure 14 , which is a structural block diagram of an electronic device 200 that can execute the above sidelobe cancellation method provided by an embodiment of this application. The electronic device 200 may be a communication device, a mobile phone, a computer, or a portable computer, etc.
[0104] The electronic device 200 further includes a processor 202 and a memory 204. Among them, the memory 204 stores a program that can execute the content in the foregoing embodiments, and the processor 202 can execute the program stored in the memory 204.
[0105] Please refer to Figure 15 , Figure 15 , which shows a structural block diagram of a computer-readable storage medium provided by an embodiment of this application. The computer-readable storage medium 400 stores a computer program 410, and the computer program 410 can be called by a processor to execute the method described in the above method embodiments.
[0106] The embodiments of the present application also provide a computer program product or a computer program. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes a sidelobe cancellation method described in any of the above various alternative implementations.
[0107] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present application.
Claims
1. A sidelobe cancellation method, characterized in that, The method includes: Performing narrow pulse selection based on the main channel signal of the radar, and obtaining interference signal samples corresponding to the auxiliary channel signal of the radar at the moment of the narrow pulse selection; Calculating a sidelobe cancellation vector based on the main channel signal and the interference signal samples; Inputting the main channel signal, the auxiliary channel signal, and the sidelobe cancellation vector into a pre-established processing model to obtain the radar echo signal after sidelobe cancellation.
2. The sidelobe cancellation method according to claim 1, wherein The expression of the processing model includes: where y(t) is the main channel signal, X is the signal vector of the auxiliary channel, and W opt is the sidelobe cancellation vector.
3. A sidelobe cancellation method according to claim 1, wherein The performing narrow pulse selection based on the main channel signal of the radar includes: Performing envelope detection on the main channel signal to determine a pulse sequence; Judging whether the pulse width of the pulse sequence exceeds a threshold; In the case of determining that the pulse sequence does not exceed the threshold, determining it as an interfering narrow pulse and performing selection in the auxiliary channel of the radar.
4. A sidelobe cancellation method according to claim 1, characterized in that, The obtaining interference signal samples corresponding to the auxiliary channel signal of the radar at the moment of the narrow pulse selection includes: Selecting the signal vector of the auxiliary channel at the moment of the narrow pulse selection; Obtaining the interference signal samples of the selected auxiliary channel.
5. A sidelobe cancellation method and apparatus, characterized in that The device includes: An acquisition module, configured to perform narrow pulse selection based on the main channel signal of the radar, and obtain interference signal samples corresponding to the auxiliary channel signal of the radar at the moment of the narrow pulse selection; A calculation module, configured to calculate a sidelobe cancellation vector based on the main channel signal and the interference signal samples; A processing module, configured to input the main channel signal, the auxiliary channel signal, and the sidelobe cancellation vector into a pre-established processing model to obtain the radar echo signal after sidelobe cancellation.
6. The sidelobe cancellation method device according to claim 5, characterized in that, The device further includes: A detection module, configured to perform envelope detection on the main channel signal to determine a pulse sequence; A judgment module, configured to judge whether the pulse width of the pulse sequence exceeds a threshold; A selection module, configured to, in the case of determining that the pulse sequence does not exceed the threshold, determine it as an interfering narrow pulse and perform selection in the auxiliary channel of the radar.
7. The sidelobe cancellation method and apparatus according to claim 5, wherein The device further includes: A screening module, configured to select the signal vector of the auxiliary channel at the moment of the narrow pulse selection; A sub-acquisition module, configured to obtain the interference signal samples of the selected auxiliary channel.
8. An electronic device, characterized in that, The electronic device includes a memory and a processor, and a computer program capable of running on the processor is stored on the memory. When the computer program is executed by the processor, the method according to any one of claims 1-4 is implemented.
9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, and the computer program can be called and executed by one or more processors to implement the method according to any one of claims 1-4.
10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, the steps of the method according to any one of claims 1-4 are implemented.