Method and device for generating low-sidelobe nonlinear frequency modulation radar signal

Abstract

The invention discloses a low-sidelobe nonlinear frequency modulation radar signal generation method and device, and belongs to the technical field of radar signal processing. The method comprises the following steps: processing a radar signal before emission to obtain a normalized frequency-time equation used for representing a signal frequency and a normalized amplitude-frequency equation used for representing a signal frequency domain amplitude; processing the normalized amplitude-frequency equation according to a preset window function shape parameter to obtain a first change equation of the normalized angular time relative to the normalized angular frequency; fourier series decomposition is carried out on the first change equation, and a second change equation of the normalized angular frequency about the normalized angular time is obtained through calculation; according to the original phase of the signal and the second change equation, calculating to obtain a third change equation about time under the condition of low sidelobe of the signal; and processing the third change equation, determining a matched filter, and generating a signal with an optimal output peak signal-to-noise ratio under a low sidelobe condition. The problem that the signal-to-noise ratio of an output peak value is reduced due to windowing can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of radar signal processing, and particularly to a method and device for generating a low sidelobe non-linear frequency modulation radar signal. Background Art

[0002] A linear frequency modulation signal (LFM) is a signal whose frequency changes linearly with time. Because of its characteristics of simple structure, easy generation and control, and convenient pulse compression, it is often used as the transmitted signal of a radar.

[0003] In the related art, a method of windowing the echo signal is usually used to reduce the problem that the strong target sidelobe of the linear frequency modulation signal covers the weak target sidelobe. However, windowing not only makes the filter no longer match the signal precisely, reducing the signal-to-noise ratio, but also makes the 3dB width of the main lobe wider, reducing the resolution.

[0004] Based on this, there is an urgent need for a method and device for generating a low sidelobe non-linear frequency modulation radar signal to solve the above technical problems. Summary of the Invention

[0005] The present invention provides a method and device for generating a low sidelobe non-linear frequency modulation radar signal, which can solve the problem of reduced signal-to-noise ratio caused by windowing in the related art. The technical solutions are as follows:

[0006] On the one hand, a method for generating a low sidelobe non-linear frequency modulation radar signal is provided. The method includes:

[0007] Processing the radar signal before transmission according to the stationary phase principle to obtain a normalized frequency-time equation for characterizing the signal frequency and a normalized amplitude-frequency equation for characterizing the signal frequency domain amplitude;

[0008] Processing the normalized amplitude-frequency equation according to a preset window function shape parameter to obtain a first variation equation of the normalized angular time with respect to the normalized angular frequency;

[0009] Performing Fourier series decomposition on the first variation equation to calculate and obtain a second variation equation of the normalized angular frequency with respect to the normalized angular time;

[0010] Calculating a third variation equation of the radar signal with respect to time under the low sidelobe condition according to the original phase of the radar signal and the second variation equation;

[0011] Processing the third variation equation according to the stationary phase principle to determine a matched filter for processing the signal echo, and generating a radar signal with an optimal output peak signal-to-noise ratio under the low sidelobe condition according to the matched filter.

[0012] On the other hand, a generating device for a low sidelobe non-linear frequency modulation radar signal is provided, and the device includes:

[0013] A first processing module, configured to process the radar signal before transmission according to the stationary phase principle, to obtain a normalized frequency-time equation for characterizing the signal frequency and a normalized amplitude-frequency equation for characterizing the signal frequency-domain amplitude;

[0014] A second processing module, configured to process the normalized amplitude-frequency equation according to a preset window function shape parameter, to obtain a first variation equation of the normalized angular time with respect to the normalized angular frequency;

[0015] A first calculation module, configured to perform Fourier series decomposition on the first variation equation, and calculate to obtain a second variation equation of the normalized angular frequency with respect to the normalized angular time;

[0016] A second calculation module, configured to calculate a third variation equation of the radar signal with respect to time under the low sidelobe condition according to the original phase of the radar signal and the second variation equation;

[0017] A third calculation module, configured to process the third variation equation according to the stationary phase principle, determine a matched filter for processing the signal echo, and generate a radar signal with an optimal output peak signal-to-noise ratio under the low sidelobe condition according to the matched filter.

[0018] On the other hand, a computer device is provided, and the computer device includes a memory and a processor. The memory is used to store a computer program, and the processor is configured to execute the computer program stored on the memory to implement the steps of the above-mentioned method for generating a low sidelobe non-linear frequency modulation radar signal.

[0019] On the other hand, a computer-readable storage medium is provided, and a computer program is stored in the storage medium. When the computer program is executed by a processor, the steps of the above-mentioned method for generating a low sidelobe non-linear frequency modulation radar signal are implemented.

[0020] On the other hand, a computer program product is provided, including a computer program. When the computer program is executed by a processor, the steps of the above-mentioned method for generating a low sidelobe non-linear frequency modulation radar signal are implemented.

[0021] The technical solution provided by the present invention can at least bring the following beneficial effects: First, the frequency and frequency-domain amplitude of the radar transmitted signal are normalized, and the processed signal is windowed using a Hamming window. Then, by further solving the windowed signal, its frequency-domain matched filter is determined. Finally, the signal echo is processed using this filter to obtain the optimal output peak signal-to-noise ratio result under specific low sidelobe conditions. Incorporating the Hamming window into the transmitted signal and performing corresponding matched filtering enables the signal to obtain the weighted effect of a Hamming window. Compared with the traditional method of directly applying the Hamming window to the signal in the echo information processing stage, the present invention can obtain the optimal output peak signal-to-noise ratio while effectively suppressing sidelobes. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 It is a flowchart of a method for generating a low sidelobe non-linear frequency modulation radar signal provided by an embodiment of the present invention;

[0024] Figure 2 It is a time-frequency diagram of a linear frequency modulation signal provided by an embodiment of the present invention;

[0025] Figure 3 It is a diagram of adding a Hamming window in the frequency domain of a linear frequency modulation signal provided by an embodiment of the present invention;

[0026] Figure 4 It is a time-frequency diagram of a non-linear frequency modulation signal provided by an embodiment of the present invention;

[0027] Figure 5 It is a three-point cross-sectional view of a linear frequency modulation signal without noise provided by an embodiment of the present invention;

[0028] Figure 6 It is a three-point cross-sectional view of a linear frequency modulation signal with a Hamming window added without noise provided by an embodiment of the present invention;

[0029] Figure 7 It is a three-point cross-sectional view of the present invention without noise provided by an embodiment of the present invention;

[0030] Figure 8 It is a three-point cross-sectional view of a linear frequency modulation signal with noise provided by an embodiment of the present invention;

[0031] Figure 9 It is a three-point cross-sectional view of a linear frequency modulation signal with a Hamming window added and with noise provided by an embodiment of the present invention;

[0032] Figure 10 It is the three - point sectional view of the present invention under noise provided by an embodiment of the present invention;

[0033] Figure 11 It is the structural diagram of the generating device of the low - sidelobe non - linear frequency - modulated radar signal provided by an embodiment of the present invention;

[0034] Figure 12 It is the hardware architecture diagram of a computer device provided by an embodiment of the present invention. Detailed implementation manners

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0036] As described above, in the related art, the received echo signal is usually windowed, and this method usually causes a decrease in the signal - to - noise ratio of the signal and a decrease in the resolution at the same time.

[0037] Based on this, the concept of the present invention is to integrate the Hamming window into the transmitted signal in advance. After passing through a matched filter with corresponding settings, the signal obtains the weighted effect of a Hamming window. Compared with the traditional method of directly windowing the signal in the echo information processing stage, this method obtains the optimal output peak signal - to - noise ratio on the premise of effectively suppressing the sidelobes.

[0038] The following describes the specific implementation manners of the above concept.

[0039] Please refer to Figure 1 , a method for generating a low - sidelobe non - linear frequency - modulated radar signal provided by an embodiment of the present invention, the method includes:

[0040] Step 100, process the radar signal before transmission according to the stationary - phase principle to obtain a normalized frequency - time equation for characterizing the signal frequency and a normalized amplitude - frequency equation for characterizing the signal frequency - domain amplitude;

[0041] Step 102, process the normalized amplitude - frequency equation according to the preset window - function shape parameters to obtain a first variation equation of the normalized angular time with respect to the normalized angular frequency;

[0042] Step 104, perform Fourier - series decomposition on the first variation equation and calculate to obtain a second variation equation of the normalized angular frequency with respect to the normalized angular time;

[0043] Step 106: Calculate a third variation equation with respect to time for the radar signal under the condition of low sidelobes according to the original phase of the radar signal and the second variation equation.

[0044] Step 108: Process the third variation equation according to the stationary phase principle to determine a matched filter for processing the signal echo, and generate a radar signal with an optimal output peak signal-to-noise ratio under the condition of low sidelobes according to the matched filter.

[0045] In the embodiment of the present invention, first, the frequency and frequency-domain amplitude of the radar transmission signal are normalized, and the processed signal is windowed using a Hamming window. Then, by further solving the windowed signal, its frequency-domain matched filter is determined. Finally, the signal echo is processed using this filter to obtain an optimal output peak signal-to-noise ratio result under specific low sidelobe conditions. Incorporating the Hamming window into the transmission signal, after corresponding matched filtering, the signal obtains a weighted effect of the Hamming window. Compared with the traditional method of directly applying the Hamming window to the signal in the echo information processing stage, the present invention obtains an optimal output peak signal-to-noise ratio on the premise of effectively suppressing sidelobes.

[0046] The following describes Figure 1 the execution manners of the respective steps shown.

[0047] First, for step 100, process the radar signal before transmission according to the stationary phase principle to obtain a normalized frequency-time equation for characterizing the signal frequency and a normalized amplitude-frequency equation for characterizing the signal frequency-domain amplitude.

[0048] In the embodiment of the present invention, first assume that the time-domain equation S T (τ) of the radar signal varying with time τ:

[0049]

[0050] where P S is the average power; T r is the pulse width; B r is the bandwidth; is the phase varying with time;

[0051] Process the time-domain equation according to the stationary phase principle to respectively determine the frequency-time equation f r with respect to time and the amplitude-frequency equation A r of the frequency-domain amplitude with respect to the signal frequency A f f (f (f r )):

[0052]

[0053] Among them, τ(f r ) is the inverse expression of the variation equation f r (τ);

[0054] Next, let the normalized angular time ω τ and the normalized angular frequency ω f be:

[0055]

[0056] Substitute the preset normalized angular time ω τ and the normalized angular frequency ω f into the frequency-time equation and the amplitude-frequency equation, and calculate to obtain the normalized frequency-time equation ω f (ω τ ) and the normalized amplitude-frequency equation A f (ω f ):

[0057]

[0058] Among them, K r = B r / T r is the modulation frequency of the transmitted signal.

[0059] Then, for step 102, process the normalized amplitude-frequency equation according to the preset window function shape parameter to obtain the first variation equation of the normalized angular time with respect to the normalized angular frequency.

[0060] The Hamming window is a relatively commonly used frequency-domain weighting method, and its expression is:

[0061] W H (ω f ) = 1 + ecosω f

[0062] Among them, e is the shape parameter of the Hamming window.

[0063] Next, according to the signal sidelobe suppression requirement, initialize the shape parameter of the Hamming window, and use the initialized Hamming window to process the normalized amplitude-frequency equation to obtain the frequency-domain amplitude of the windowed radar signal:

[0064]

[0065] Among them, C is an undetermined energy conservation constant;

[0066] Furthermore, from the expression of the frequency-domain amplitude varying with frequency and the specific expression of the frequency-domain amplitude, it can be obtained that:

[0067] W H (ω f )dω f =Cdω τ

[0068] Considering the correspondence between time and frequency at the edge of the effective value, i.e., ω f (±π)=±π; substituting the frequency-domain amplitude of the windowed radar signal into the normalized amplitude-frequency equation for calculation, and integrating the calculation result at the edge of the effective values of time and frequency, the first variation equation is obtained:

[0069] ω τ =ω f +esinω f 。

[0070] For step 104, performing Fourier series decomposition on the first variation equation, the second variation equation of the normalized angular frequency with respect to the normalized angular time is calculated.

[0071] Using the Fourier series method to solve the first variation equation determined in the above process, the second variation equation can be obtained:

[0072]

[0073] where J n (·) is the Bessel function of the first kind of integer order, and its definition is:

[0074]

[0075] For step 106, according to the original phase of the radar signal and the second variation equation, the third variation equation of the radar signal under the low sidelobe condition with respect to time is calculated.

[0076] In the embodiment of the present invention, according to the second variation equation, the original phase of the radar signal is calculated

[0077]

[0078] Then substituting the original phase into the time-domain equation, the third variation equation is calculated:

[0079]

[0080] For step 108, according to the stationary phase principle, the third variation equation is processed to determine the matched filter for processing the signal echo, and a radar signal with the optimal output peak signal-to-noise ratio under the low sidelobe condition is generated according to the matched filter.

[0081] In the embodiment of the present invention, the third variation equation is processed according to the stationary phase principle to obtain the frequency domain equation S of the radar signal T (ω f ):

[0082]

[0083] Among them, the phase is:[[]]END]]

[0084]

[0085] From this, the initial expression of the matched filter can be obtained:[[]]END]]

[0086]

[0087] Furthermore, the normalized angular frequency in the matched filter is replaced with the signal frequency f mentioned in the above process r , and the expansion of the phase φ(ω f ) calculated in the above process is substituted into the matched filter. According to the frequency domain equation, the matched filter H(f r ) for processing the signal echo is determined under the shape parameter of the Hamming window:[[]]END]]

[0088]

[0089] The echo of the radar signal is processed by using the matched filter to obtain a filtered signal S R (f r ) with the optimal output peak signal-to-noise ratio under the condition of low sidelobes:[[]]END]]

[0090] S R (f r ) = S T (f r ) × H(f r )

[0091] Among them, S T (f r ) is the expression of the radar signal in the frequency domain.[[]]END]]

[0092] Next, an embodiment is used to verify the feasibility of the above method.[[]]END]]

[0093] In this embodiment, a point target simulation is taken as an example. In this embodiment, three point targets at different positions are set, with a distance of 500 meters between adjacent two points, and the shape parameter e of the Hamming window is 0.4 / 0.6. The specific simulation parameters of the point target are shown in Table 1 below:[[]]END]]

[0094] Table 1

[0095]

[0096]

[0097] Figure 2 is the time-frequency diagram of the chirp signal; Figure 3 is the frequency-domain diagram of the chirp signal with a Hamming window added, and a Hamming window with a shape parameter of e = 0.4 / 0.6 is added to the signal in the frequency domain; Figure 4 is the time-frequency diagram of the non-linear chirp signal of this patent. Matched filtering is performed in the frequency domain. By comparison, it can be seen that this invention patent obtains the same weighted effect as Figure 3 the Hamming window.

[0098] In the embodiment, six groups of comparative experiments are set up. In the first and fourth groups, point targets are imaged by using LFM without a window. In the second and fifth groups, point targets are imaged by using LFM with a Hamming window. In the third and sixth groups of experiments, a low sidelobe non-linear chirp radar signal generation and processing method with the optimal output peak signal-to-noise ratio of this invention is used. No noise is added in the first three groups, and complex Gaussian noise with a signal-to-noise ratio of -15 dB is added in the last three groups. Due to the addition of noise, traditional metrics cannot be used for evaluation. In this embodiment, the peak signal-to-noise ratio is reflected by comparing the average sidelobe power.

[0099] The results of the three-point target profile diagrams without noise in the first three groups are as Figures 5 - 7 shown, and the results of the three-point target profile diagrams with noise in the last three groups are as Figures 8 - 10 ; In the six groups of simulation experiments, the three-point mean values are taken for data comparison. The resolution (Resolution), peak sidelobe ratio (PSLR), integrated sidelobe ratio (ISLR) under the condition of no noise, and the results of the output peak signal-to-noise ratio under the condition of noise are shown in Table 2 below. Table 2 is the point target imaging result (average).

[0100] Table 2

[0101]

[0102] Comparing the experimental results of the first three groups, although this embodiment does not directly add a Hamming window, it still achieves the effect of adding a Hamming window. By changing the transmitted signal and matched filtering, the peak signal-to-noise ratio after pulse compression is directly improved. Comparing the experimental results of the last three groups, the normalized average power after adding a window will deteriorate, but the normalized noise average power in this embodiment will return to the state before adding the window, that is, the state without adding a window.

[0103] Please refer to Figure 11 , this invention embodiment provides a device for generating a low sidelobe non-linear chirp radar signal. The device includes:

[0104] The first processing module S1 is used to process the radar signal before transmission according to the stationary phase principle, and obtain a normalized frequency-time equation for characterizing the signal frequency and a normalized amplitude-frequency equation for characterizing the signal frequency-domain amplitude;

[0105] The second processing module S2 is used to process the normalized amplitude-frequency equation according to the preset window function shape parameter, and obtain a first variation equation of the normalized angular time with respect to the normalized angular frequency;

[0106] The first calculation module S3 is used to perform Fourier series decomposition on the first variation equation, and calculate a second variation equation of the normalized angular frequency with respect to the normalized angular time;

[0107] The second calculation module S4 is used to calculate a third variation equation of the radar signal with respect to time under the low sidelobe condition according to the original phase of the radar signal and the second variation equation;

[0108] The third calculation module S5 is used to process the third variation equation according to the stationary phase principle, determine a matched filter for processing the signal echo, and generate a radar signal with an optimal output peak signal-to-noise ratio under the low sidelobe condition according to the matched filter.

[0109] In the embodiment of the present invention, when the first processing module S1 performs processing on the radar signal before transmission according to the stationary phase principle to obtain a normalized frequency-time equation for characterizing the signal frequency and a normalized amplitude-frequency equation for characterizing the signal frequency-domain amplitude, it is specifically used to perform the following operations:

[0110] Determine the time-domain equation S T (τ) of the radar signal varying with time τ:

[0111]

[0112] where P S is the average power; T r is the pulse width; B r is the bandwidth; is the phase varying with time;

[0113] Process the time-domain equation according to the stationary phase principle, and respectively determine the frequency-time equation f r of the signal frequency with respect to time f r (τ), and the amplitude-frequency equation A f of the frequency-domain amplitude with respect to the signal frequency A f (f r ):

[0114]

[0115] where τ(f r ) is the inverse expression of the variation equation f r (τ);

[0116] Substitute the preset normalized angular time ω τ and the normalized angular frequency ω f into the frequency-time equation and the amplitude-frequency equation, and calculate to obtain the normalized frequency-time equation ω f (ω τ ) and the normalized amplitude-frequency equation A f (ω f ):

[0117]

[0118] where K r =B r / T r is the frequency modulation rate of the transmitted signal.

[0119] In an embodiment of the present invention, when the second processing module S2 executes the operation of processing the normalized amplitude-frequency equation according to the preset window function shape parameter to obtain the first variation equation of the normalized angular time with respect to the normalized angular frequency, it is specifically used to perform the following operations:

[0120] According to the signal sidelobe suppression requirement, initialize the shape parameter of the Hamming window, and use the initialized Hamming window to process the normalized amplitude-frequency equation to obtain the frequency-domain amplitude of the windowed radar signal:

[0121]

[0122] where C is an undetermined energy conservation constant;

[0123] Substitute the frequency-domain amplitude of the windowed radar signal into the normalized amplitude-frequency equation for calculation, and integrate the calculation result at the edges of the time and frequency effective values to obtain the first variation equation:

[0124] ω τ =ω f +esinω f

[0125] where e is the shape parameter of the Hamming window.

[0126] In an embodiment of the present invention, when the first calculation module S3 executes the Fourier series decomposition of the first variation equation to calculate the second variation equation of the normalized angular frequency with respect to the normalized angular time, it is specifically used to perform the following operations:

[0127]

[0128] where Jn (·) is the Bessel function of the first kind of integer order.

[0129] In an embodiment of the present invention, when the second calculation module S4 calculates the third variation equation with respect to time under the condition of low sidelobes of the radar signal according to the original phase of the radar signal and the second variation equation, it is specifically used to perform the following operations:

[0130] Calculate the original phase of the radar signal according to the second variation equation

[0131]

[0132] Substitute the original phase into the time-domain equation to calculate the third variation equation:

[0133]

[0134] In an embodiment of the present invention, when the third processing module S5 processes the third variation equation according to the stationary phase principle to determine a matched filter for processing the signal echo, and generates a radar signal with an optimal output peak signal-to-noise ratio under the condition of low sidelobes according to the matched filter, it is specifically used to perform the following operations:

[0135] Process the third variation equation according to the stationary phase principle to obtain the frequency-domain equation S T (ω f ):

[0136]

[0137] Determine a matched filter H(f r ) for processing the signal echo according to the frequency-domain equation under the shape parameters of the Hamming window:

[0138]

[0139] Process the echo of the radar signal with the matched filter to obtain a filtered signal S R (f r ):

[0140] S R (f r )=S T (f r )×H(f r )

[0141] Wherein, S T (f r ) is the expression of the radar signal in the frequency domain.

[0142] It should be noted that: for the generating device of the low sidelobe non-linear frequency modulation radar signal provided in the above embodiments, only the division of the above functional modules is used for illustration. In practical applications, the above functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the generating device of the low sidelobe non-linear frequency modulation radar signal provided in the above embodiments and the embodiments of the generating method of the low sidelobe non-linear frequency modulation radar signal belong to the same concept. For the specific implementation process, please refer to the method embodiments and will not be elaborated here.

[0143] An embodiment of the present application also provides a computer device. Please refer to Figure 12 , the computer device includes a processor and a memory. The memory stores at least one instruction, at least one program, a code set or an instruction set. The at least one instruction, at least one program, the code set or the instruction set is loaded and executed by the processor to implement the generating method of the low sidelobe non-linear frequency modulation radar signal provided in each of the above method embodiments.

[0144] An embodiment of the present application also provides a computer-readable storage medium. The computer-readable storage medium stores at least one instruction, at least one program, a code set or an instruction set. The at least one instruction, at least one program, the code set or the instruction set is loaded and executed by the processor to implement the generating method of the low sidelobe non-linear frequency modulation radar signal provided in each of the above method embodiments.

[0145] An embodiment of the present application also provides a computer program product. The computer program product includes a computer program. The processor of the computer device reads the computer program from the computer-readable storage medium, and the processor executes the computer program to enable the computer device to execute the generating method of the low sidelobe non-linear frequency modulation radar signal described in any one of the above embodiments.

[0146] For the convenience of description, when describing the above system or device, various modules or units are described separately according to functions. Of course, when implementing the present application, the functions of each unit can be implemented in one or more software and / or hardware.

[0147] From the description of the above embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of this application, in essence, or the part that contributes to the prior art can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0148] Finally, it should also be noted that in this text, relational terms such as first, second, third, and fourth are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0149] The above are only the preferred embodiments of this application. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of this application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of this application.

Claims

1. A method for generating a low sidelobe nonlinear frequency modulation radar signal, characterized in that: The method comprises: The radar signal before transmission is processed according to the stationary phase principle to obtain a normalized frequency-time equation for characterizing the signal frequency and a normalized amplitude-frequency equation for characterizing the signal frequency domain amplitude; Processing the normalized amplitude-frequency equation according to preset window function shape parameters to obtain a first variation equation of the normalized angular time with respect to the normalized angular frequency; Performing Fourier series decomposition on the first variation equation to calculate and obtain a second variation equation of the normalized angular frequency with respect to the normalized angular time; Calculating a third variation equation of the radar signal with respect to time under a low sidelobe condition according to the original phase of the radar signal and the second variation equation; The third variation equation is processed according to the stationary phase principle to determine a matched filter for processing the signal echo, and a radar signal with an optimal output peak signal-to-noise ratio under low sidelobe conditions is generated according to the matched filter.

2. The method according to claim 1, characterized in that The radar signal before transmission is processed according to the stationary phase principle to obtain a normalized frequency-time equation for characterizing the signal frequency and a normalized amplitude-frequency equation for characterizing the signal frequency domain amplitude, including: Determine the time domain equation S of the radar signal changing with time τ T (τ): Among them, P S is the average power; T r is the pulse width; B r is bandwidth; is the phase that changes with time; The time domain equation is processed according to the stationary phase principle to determine the signal frequency f r The frequency-time equation f about time r (τ), and the frequency domain amplitude A f The amplitude-frequency equation A about the signal frequency f (f r ): Among them, τ(f r ) is the change equation f r Inverse expression of (τ); The preset normalized angle time ω τ and the normalized angular frequency ω f Substitute into the frequency-time equation and the amplitude-frequency equation to calculate the normalized frequency-time equation ω f (ω τ ) and the normalized amplitude-frequency equation A f (ω f ): Among them, K r =B r / T r Modulate the frequency of the transmitted signal.

3. The method according to claim 2, characterized in that The step of processing the normalized amplitude-frequency equation according to the preset window function shape parameters to obtain a first variation equation of the normalized angular time with respect to the normalized angular frequency includes: According to the signal sidelobe suppression requirements, the shape parameters of the Hamming window are initialized, and the normalized amplitude-frequency equation is processed using the initialized Hamming window to obtain the frequency domain amplitude of the windowed radar signal: Where C is the energy conservation constant to be determined; Substitute the frequency domain amplitude of the windowed radar signal into the normalized amplitude-frequency equation for calculation, and integrate the calculation result at the edge of the effective value of time and frequency to obtain the first change equation: oh τ =ω f +isinω f Where e is the shape parameter of the Hamming window.

4. The method according to claim 3, characterized in that The second change equation is established by the following formula: Among them, J n (·) is the Bessel function of the first kind of integer order.

5. The method according to claim 4, characterized in that The step of calculating, according to the original phase of the radar signal and the second variation equation, a third variation equation of the radar signal with respect to time under the low sidelobe condition comprises: According to the second transformation equation, the original phase of the radar signal is calculated Substituting the original phase into the time domain equation, the third change equation is calculated:

6. The method according to claim 5, characterized in that The method of processing the third variation equation according to the stationary phase principle, determining a matched filter for processing a signal echo, and generating a radar signal with an optimal output peak signal-to-noise ratio under a low sidelobe condition according to the matched filter, comprises: The third variation equation is processed according to the stationary phase principle to obtain the frequency domain equation S of the radar signal: T (ω f ): According to the frequency domain equation, the matched filter H(f r ): The radar signal echo is processed by the matched filter to obtain a filtered signal S with an optimal output peak signal-to-noise ratio under low sidelobe conditions. R (f r ): S R (f r )=S T (f r )×H(f r ) Among them, S T (f r ) is the expression of radar signal in frequency domain.

7. A device for generating a low sidelobe nonlinear frequency modulation radar signal, characterized in that: The device comprises: The first processing module is used to process the radar signal before transmission according to the stationary phase principle to obtain a normalized frequency-time equation for characterizing the signal frequency and a normalized amplitude-frequency equation for characterizing the signal frequency domain amplitude; A second processing module, used for processing the normalized amplitude-frequency equation according to a preset window function shape parameter to obtain a first variation equation of the normalized angular time with respect to the normalized angular frequency; A first calculation module, configured to perform Fourier series decomposition on the first change equation to calculate a second change equation of the normalized angular frequency with respect to the normalized angular time; A second calculation module, used for calculating a third change equation of the radar signal with respect to time under a low sidelobe condition according to the original phase of the radar signal and the second change equation; The third calculation module is used to process the third change equation according to the stationary phase principle, determine the matched filter used to process the signal echo, and generate a radar signal with an optimal output peak signal-to-noise ratio under low sidelobe conditions according to the matched filter.

8. A computer device, characterized in that: The computer device includes a memory and a processor, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory to implement the steps of any one of the methods described in claims 1-6.

9. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method described in any one of claims 1 to 6 are implemented.

10. A computer program product, characterized in that The method comprises a computer program, wherein when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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