Radar signal modulation type classification method based on pulse compression characteristics

Abstract

A radar signal modulation type classification method based on pulse compression characteristics. The method comprises: using pulse compression characteristics of a radar signal to calculate the ratio of a main lobe width after pulse compression to a pulse width for the signal, a square of the signal and a fourth power of the signal, so as to identify a simple signal, a binary phase-coded signal and a quaternary phase-coded signal; and for the remaining unclassified signals, using different delay autocorrelation coefficients to calculate the modulation slopes of the remaining unclassified signals, and on the basis of calculated modulation slope results, distinguishing a linear frequency modulation signal from a non-linear frequency modulation signal. In the method, pulse compression characteristics of a radar signal are used to distinguish a simple signal, a binary phase-coded signal, a quaternary phase-coded signal, a linear frequency modulation signal and a non-linear frequency modulation signal by means of a convolution operation and other simple operations. Compared with other algorithms, the method has the advantages of a small calculation amount, a fast identification speed, a simple process, and a low requirement for a signal-to-noise ratio.

Description

A Radar Signal Modulation Type Classification Method Based on Pulse Compression Characteristics Technical Field

[0001] This invention belongs to the field of radar signal pulse analysis and identification technology, and in particular relates to a radar signal modulation type classification method based on pulse compression characteristics. Background Technology

[0002] Intra-pulse modulation characteristics of radar signals are an important component of radar parameters. Common intra-pulse modulation forms include simple, binary-coded, four-phase-coded, linear frequency modulation, and nonlinear modulation. Pulse compression technology is the most common signal processing technique in modern radar. It refers to converting a wide pulse modulated by the radar's transmitted frequency or phase into a narrow pulse signal during reception using autocorrelation. Through pulse compression, radar can achieve high range resolution while transmitting a wide pulse signal. Simple signals do not employ pulse compression, so their main lobe width after autocorrelation is equal to the transmitted signal pulse width. However, modulated signals using pulse compression have a main lobe width after autocorrelation that is much smaller than the transmitted pulse width. Common methods for classifying radar pulse signals include instantaneous frequency measurement, time-frequency analysis, and bandwidth ratio-based methods. Instantaneous frequency measurement classifies the intra-pulse modulation characteristics of radar signals based on the instantaneous frequency characteristics of different radar signal intra-pulse modulation features. However, instantaneous frequency measurement is extremely sensitive to noise, making it difficult to meet the needs of practical electronic reconnaissance systems. The bandwidth ratio-based method calculates the signal type by performing a Fast Fourier Transform (FFT) on the square of the signal and then calculating the bandwidth ratio. In practical applications, radar radiation source signals are subject to noise interference and channel fluctuations during propagation and reception, resulting in significant variations in SNR and making accurate measurement of the signal's spectral width difficult. Time-frequency analysis methods involve large computational loads and numerous parameters, leading to unsatisfactory application results. Summary of the Invention

[0003] The purpose of this invention is to solve the problems mentioned in the background art and to propose a radar signal modulation type classification method based on pulse compression characteristics. This method has the advantages of low computational load, fast identification speed, simple process, convenient engineering implementation, and low signal-to-noise ratio requirements.

[0004] To achieve the objectives of this invention, a radar signal modulation type classification method based on pulse compression characteristics is disclosed. This method utilizes the pulse compression characteristics of radar signals to calculate the ratio of the main lobe width to the pulse width after pulse compression of the signal, the square of the signal, and the fourth power of the signal, thereby identifying simple signals, binary coded signals, and quadrature coded signals. For the remaining unclassified signals, different delay autocorrelation coefficients are used to calculate their modulation slopes, and the calculated modulation slope results are used to distinguish between linear frequency modulated signals and nonlinear frequency modulated signals.

[0005] Furthermore, the specific steps include:

[0006] Step 1: Perform autocorrelation calculation on the radar IQ signal, solve for its maximum value, and logarithmically normalize the autocorrelation result based on the maximum value;

[0007] Step 2: Detect the 3dB main lobe width of the normalized result, calculate the ratio of the main lobe width to the original signal pulse width. If the ratio is close to 1, the signal is determined to be a simple signal; otherwise, it is a pulse compression signal.

[0008] Step 3: Squaring the I and Q channels of the IQ signal respectively, and repeating steps 1 and 2. If the ratio is close to 1, it is determined to be a binary phase coded signal.

[0009] Step 4: Perform the fourth power operation on the I and Q paths of the IQ signal respectively, and repeat steps 1 and 2. If the ratio is close to 1, it is determined to be a four-phase coded signal.

[0010] Step 5: Apply different delay correlation coefficients to the remaining unclassified signals, perform delay autocorrelation calculations, calculate their modulation slopes respectively, and determine whether they are linear frequency modulation signals based on whether the modulation slopes are the same.

[0011] Furthermore, when the ratio of the main lobe width to the original signal pulse width is 1 ± 0.1, it is considered that the ratio is close to 1.

[0012] Furthermore, step 1 specifically includes the following steps:

[0013] Perform autocorrelation on the signal and normalize the result R according to the following formula. x (n):

[0014] In the formula, x(n) is the radar IQ sampling signal, N is the total sampling length, and h is the number of time-domain offset points of the autocorrelation function.

[0015] Further, in step 2, the normalized result R is calculated. x (n) The ratio of the 3dB width to the original signal pulse width.

[0016] Furthermore, in step 3, when the ratio is close to 1, the signal is a simple signal. For signals that do not meet the threshold, the real part re and the imaginary part im of x(n) are squared using the following formula to obtain the y(n) signal: y(n).re=(x(n).re) 2 y(n).im = (x(n).im) 2

[0017] Repeat steps 1 and 2 for y(n) to calculate the normalized result R of y(n). y (n) The ratio of the 3dB width to the original signal pulse width.

[0018] Further, in step 4, when the ratio is close to 1, the signal is a binary coded signal. The signal that does not meet the threshold is raised to the fourth power to obtain the z(n) signal: z(n).re = (x(n).re) 4 z(n).im = (x(n).im) 4

[0019] Repeat steps 1 and 2 for z(n) to calculate the normalized result R z (n) The ratio of the 3dB width to the original signal pulse width;

[0020] When the ratio is greater than or equal to 1, the signal is a quaternary coded signal, and the signal that does not meet the threshold is other compressed signals.

[0021] Further, in step 5, different delay coefficients a1 and a2 are selected, where 0.5 < a1 < 1 and 0 < a2 < 0.5, and delay autocorrelation operations are performed to calculate their modulation slopes k1 and k2 respectively;

[0022] When k1 = k2, the signal is a linear frequency modulation signal; otherwise, it is a non-linear frequency modulation signal.

[0023] To achieve the object of the present invention, the present invention also discloses a radar signal modulation type classification system based on pulse compression characteristics, including the following modules:

[0024] Autocorrelation logarithmic normalization module, perform autocorrelation operation on the radar IQ signal, solve its maximum value, and perform logarithmic normalization on the autocorrelation result according to the maximum value;

[0025] Simple signal separation module, detect the 3dB main lobe width of the normalized result, calculate the ratio of the main lobe width to the original signal pulse width. If the ratio is close to 1, it is determined that the signal is a simple signal, otherwise it is a pulse compression signal;

[0026] Binary coded signal separation module, square the I channel and Q channel of the IQ signal respectively, and repeat the steps adopted by the autocorrelation logarithmic normalization module and the simple signal separation module. If the ratio is close to 1, it is determined that the signal is a binary coded signal;

[0027] Quaternary coded signal separation module, raise the I channel and Q channel of the IQ signal to the fourth power respectively, and repeat the steps adopted by the autocorrelation logarithmic normalization module and the simple signal separation module. If the ratio is close to 1, it is determined that the signal is a quaternary coded signal;

[0028] Linear frequency modulation signal and non-linear frequency modulation signal separation module, adopt different delay correlation coefficients for the remaining unclassified signals, perform delay autocorrelation operations, calculate their modulation slopes respectively, and judge whether it is a linear frequency modulation signal according to whether the modulation slopes are the same.

[0029] To achieve the objectives of this invention, an electronic device is also disclosed, including a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor is used to execute a radar signal modulation type classification method based on pulse compression characteristics.

[0030] Compared with the prior art, the significant progress of the present invention is as follows: 1) By utilizing the pulse compression characteristics of radar signals, simple signals, binary coded signals, quadrature coded signals, linear frequency modulation and nonlinear frequency modulation signals can be distinguished through convolution operation and other simple operations; 2) Compared with other algorithms, it has a small amount of computation and has the advantages of fast recognition speed, simple process and low signal-to-noise ratio requirement.

[0031] To more clearly illustrate the functional characteristics and structural parameters of the present invention, further explanation is provided below in conjunction with the accompanying drawings and specific embodiments. Attached Figure Description

[0032] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0033] Figure 1 is a flowchart of a radar signal modulation type classification method based on pulse compression characteristics;

[0034] Figure 2 is a schematic diagram of the calculation of the 3dB main lobe width. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] As shown in Figures 1 and 2, a radar signal modulation type classification method based on pulse compression characteristics is proposed. This method calculates the main lobe width to pulse width ratio after pulse compression of the signal, signal square, and signal fourth power, using the pulse compression characteristics of the radar signal to identify simple signals, binary phase-coded signals, and quadrature phase-coded signals. For the remaining unclassified signals, different delay autocorrelation coefficients are used to calculate their modulation slope. Based on the calculated modulation slope results, linear frequency modulation (FM) signals and nonlinear frequency modulation (FM) signals are distinguished. The specific implementation includes the following steps:

[0037] Step 1: Perform autocorrelation calculation on the radar IQ signal, solve for its maximum value, and logarithmically normalize the autocorrelation result based on the maximum value;

[0038] Step 2: Detect the 3dB main lobe width of the normalized result, calculate the ratio of the main lobe width to the original signal pulse width. If the ratio is close to 1, the signal is determined to be a simple signal; otherwise, it is a pulse compression signal.

[0039] Step 3: Squaring the I and Q paths of the IQ signal respectively, repeating steps 1 and 2. If the ratio is close to 1, it is determined to be a binary phase-coded signal. Specifically, squaring the I and Q paths of the IQ signal respectively, performing autocorrelation on the squared IQ signal, solving for its maximum value, and log-normalizing the autocorrelation result based on the maximum value. Detecting the 3dB main lobe width of the normalized result, calculating the ratio of the main lobe width to the original signal pulse width. If the ratio is 1 ± 0.1, it is determined to be a binary phase-coded signal.

[0040] Step 4: Perform a fourth power operation on the I and Q paths of the IQ signal respectively, and repeat steps 1 and 2. If the ratio is close to 1, it is determined to be a four-phase coded signal. Specifically, perform a fourth power operation on the I and Q paths of the IQ signal respectively, perform an autocorrelation operation on the IQ signal after the fourth power operation, solve for its maximum value, and perform logarithmic normalization on the autocorrelation result based on the maximum value. Detect the 3dB main lobe width of the normalized result, and calculate the ratio of the main lobe width to the original signal pulse width. If the ratio is 1±0.1, it is determined to be a four-phase coded signal.

[0041] Step 5: Apply different delay correlation coefficients to the remaining unclassified signals, perform delay autocorrelation calculations, calculate their modulation slopes respectively, and determine whether they are linear frequency modulation signals based on whether the modulation slopes are the same.

[0042] Specifically, when the ratio of the main lobe width to the original signal pulse width is 1 ± 0.1, it is considered that the ratio is close to 1.

[0043] Specifically, step 1 includes the following steps:

[0044] Perform autocorrelation on the signal and normalize the result R according to the following formula. x (n):

[0045] In the formula, x(n) is the radar IQ sampling signal, N is the total sampling length, and h is the number of time-domain offset points of the autocorrelation function.

[0046] Specifically, in step 2, the normalized result R is calculated. x (n) The ratio of 3dB width to the original signal pulse width;

[0047] Specifically, in step 3, when the ratio is close to 1, the signal is a simple signal. For signals that do not meet the threshold, the following formula is used to square the real part re and the imaginary part im of x(n) respectively to obtain the y(n) signal. That is, for the signals that do not meet the simple signal judgment condition in step 2, the following formula is used to square the real part re and the imaginary part im of x(n) respectively to obtain the y(n) signal: y(n).re = (x(n).re) 2 y(n).im = (x(n).im) 2

[0048] Repeat steps 1 and 2 for y(n), and calculate the normalized result R y (n) 3dB width to the ratio of the original signal pulse width.

[0049] Specifically, in step 4, when the ratio is close to 1, the signal is a binary coded signal. For signals that do not meet the threshold, perform a fourth-power operation to obtain the z(n) signal. That is: for the signals that do not meet the binary coded signal judgment condition in step 3, perform a fourth-power operation to obtain the z(n) signal: z(n).re = (x(n).re) 4 z(n).im = (x(n).im) 4

[0050] Repeat steps 1 and 2 for z(n) and calculate the normalized result R z (n) 3dB width to the ratio of the original signal pulse width.

[0051] When the ratio is 1 ± 0.1, the signal is a quaternary coded signal, and the signals that do not meet the threshold are other compressed signals.

[0052] Select different delay coefficients a1 and a2, where 0.5 < a1 < 1 and 0 < a2 < 0.5, and perform delay autocorrelation operations to calculate their modulation slopes k1 and k2 respectively.

[0053] When k1 = k2, the signal is a linear frequency modulation signal; otherwise, it is a non-linear frequency modulation signal.

[0054] Based on the method of the above embodiments, the present invention also provides a radar signal modulation type classification system based on pulse compression characteristics, including the following modules:

[0055] Autocorrelation logarithmic normalization module, perform autocorrelation operation on the radar IQ signal, solve its maximum value, and perform logarithmic normalization on the autocorrelation result according to the maximum value;

[0056] Simple signal separation module, detect the 3dB main lobe width of the normalized result, calculate the ratio of the main lobe width to the original signal pulse width. If the ratio is close to 1, it is determined that the signal is a simple signal, otherwise it is a pulse compression signal;

[0057] The binary phase-coded signal separation module performs squaring operations on the I and Q paths of the IQ signal respectively, repeating the steps used in the autocorrelation logarithmic normalization module and the simple signal separation module. If the ratio is close to 1, it is determined to be a binary phase-coded signal. Specifically, the binary phase-coded signal separation module performs squaring operations on the I and Q paths of the IQ signal respectively, performs autocorrelation operations on the squared IQ signals, solves for the maximum value, and performs logarithmic normalization on the autocorrelation result based on the maximum value. It detects the 3dB main lobe width of the normalized result and calculates the ratio of the main lobe width to the original signal pulse width. If the ratio is 1±0.1, it is determined to be a binary phase-coded signal.

[0058] The four-phase encoded signal separation module performs a fourth-power operation on the I and Q paths of the IQ signal, similar to the steps used in the autocorrelation logarithmic normalization module and the simple signal separation module. If the ratio is close to 1, it is determined to be a four-phase encoded signal. Specifically, the four-phase encoded signal separation module performs a fourth-power operation on the I and Q paths of the IQ signal, performs an autocorrelation operation on the IQ signal after the fourth power operation, solves for its maximum value, and performs logarithmic normalization on the autocorrelation result based on the maximum value. It then detects the 3dB main lobe width of the normalized result and calculates the ratio of the main lobe width to the original signal pulse width. If the ratio is 1±0.1, it is determined to be a four-phase encoded signal.

[0059] The linear frequency modulation (LFM) signal and nonlinear frequency modulation (NFM) signal separation module performs time-delay autocorrelation calculations on the remaining unclassified signals using different time-delay correlation coefficients, calculates their modulation slopes separately, and determines whether a signal is a LFM signal based on whether the modulation slopes are the same.

[0060] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the radar signal modulation type classification method based on pulse compression characteristics described in the above embodiments.

[0061] Example

[0062] In one embodiment, the signal is an IQ complex signal, and the radar signal modulation type classification method based on pulse compression characteristics is as follows:

[0063] S1. Perform autocorrelation calculation on the radar IQ signal, solve for its maximum value, and perform logarithmic normalization on the autocorrelation result based on the maximum value;

[0064] S2. Separate simple signals from the signal;

[0065] S3. Separate the BPSK signal from the remaining signal;

[0066] S4. Separate the QPSK signal from the remaining signal;

[0067] S5. Differentiate between LFM and NLFM signals.

[0068] Specifically, in this embodiment, the specific steps of S2 are as follows:

[0069] S2-1, Autocorrelation calculation of IQ signals;

[0070] S2-2, Calculate the autocorrelation main lobe width;

[0071] S2-3. Calculate the main lobe width / pulse width. If it equals 1, it is a simple signal; otherwise, proceed to S3.

[0072] Specifically, in this embodiment, the specific steps of S3 are as follows:

[0073] S3-1, IQ signals respectively I 2 and Q 2 A new signal is formed;

[0074] S3-2, Calculate I 2 Q 2 Autocorrelation calculation;

[0075] S3-3, Calculate I 2 Q 2 Autocorrelation main lobe width;

[0076] S3-4, Calculate I 2 Main width / pulse width: if it equals 1, it is a BPSK signal; otherwise, proceed to S4.

[0077] Specifically, in this embodiment, step S4 is as follows:

[0078] S4-1, IQ signals respectively I 4 and Q 4 Forming new signals;

[0079] S4-2, Calculate I 2 Q 2 Autocorrelation calculation;

[0080] S4-3, Calculate I 2 Q 2 Autocorrelation main lobe width;

[0081] S4-4, Calculate I 2 Main width / pulse width.

[0082] Specifically, in this embodiment, S5 distinguishes between LFM and NLFM, and uses the time-delay correlation method to calculate the modulation slope of the signal. The specific steps are as follows:

[0083] S5-1. Assuming a delay coefficient of 0.4, construct signal A1;

[0084] S5-2, Take the conjugate of A1 to get A1';

[0085] S5-3. Multiply A1′ by the original signal to obtain a new signal B1;

[0086] S5-4. Calculate the frequency F1 of B1;

[0087] S5-5, the modulation slope is K1 = F1 / 0.4;

[0088] S5-6. Assuming a delay coefficient of 0.6, construct signal A2;

[0089] S5-7, Take the conjugate of A2 to get A2';

[0090] S5-8. Multiply A2′ by the original signal to obtain the new signal B2;

[0091] S5-9, Calculate the frequency F2 of B2;

[0092] S5-10, Modulation slope K2 = F2 / 0.6;

[0093] If S5-11 and K1 = K2, then it is LFM; otherwise, it is NLFM.

[0094] Specifically, the relevant processing methods for different encoding methods are as follows: distinguishing between simple signals (NM), two-phase encoders (BPSK), four-phase encoders (QPSK), linear frequency modulation signals (LFM), and nonlinear frequency modulation signals (NLFM).

[0095] Table 1. Related processing methods for different encoding methods

[0096] As shown in Table 1, the specific processing method is as follows:

[0097] 1. Pulse compression, i.e. signal autocorrelation, find the 3dB bandwidth;

[0098] 2. IQ data, I squared, Q squared, BPSK degenerates into NM signal;

[0099] 3. IQ data is I to the power of 4 and Q to the power of 4, QPSK degenerates into mm signal;

[0100] 4. Delay cross-correlation method: Calculate the LFM modulation slope. With different delay parameters, the calculation results of LFM are the same, but the calculation results of NLFM are different.

[0101] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0102] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A radar signal modulation type classification method based on pulse compression characteristics, characterized in that, The pulse compression characteristics of radar signals are used to calculate the pulse compression ratio of the main lobe width to the pulse width of the signal, the square of the signal, and the fourth power of the signal, and to identify simple signals, binary coded signals, and quadrature coded signals. For the remaining unclassified signals, different delay autocorrelation coefficients are used to calculate their modulation slope, and the calculated modulation slope results are used to distinguish between linear frequency modulation signals and nonlinear frequency modulation signals.

2. The radar signal modulation type classification method based on pulse compression characteristics according to claim 1, characterized in that, Specifically, the following steps are included: Step 1: Perform autocorrelation calculation on the radar IQ signal, solve for its maximum value, and logarithmically normalize the autocorrelation result based on the maximum value; Step 2: Detect the 3dB main lobe width of the normalized result, calculate the ratio of the main lobe width to the original signal pulse width. If the ratio is close to 1, the signal is determined to be a simple signal; otherwise, it is a pulse compression signal. Step 3: Squaring the I and Q channels of the IQ signal respectively, and repeating steps 1 and 2. If the ratio is close to 1, it is determined to be a binary phase coded signal. Step 4: Perform the fourth power operation on the I and Q paths of the IQ signal respectively, and repeat steps 1 and 2. If the ratio is close to 1, it is determined to be a four-phase coded signal. Step 5: Apply different delay correlation coefficients to the remaining unclassified signals, perform delay autocorrelation calculations, calculate their modulation slopes respectively, and determine whether they are linear frequency modulation signals based on whether the modulation slopes are the same.

3. The radar signal modulation type classification method based on pulse compression characteristics according to claim 2, characterized in that, When the ratio of the main lobe width to the original signal pulse width is 1 ± 0.1, it is considered that the ratio is close to 1.

4. The radar signal modulation type classification method based on pulse compression characteristics according to claim 2, characterized in that, Step 1 specifically includes the following steps: Perform autocorrelation on the signal, and normalize the autocorrelation result R according to the following formula. x (n): In the formula, x(n) is the radar IQ sampling signal, N is the total sampling length, and h is the number of time-domain offset points of the autocorrelation function.

5. The radar signal modulation type classification method based on pulse compression characteristics according to claim 4, characterized in that, In step 2, the normalized result R is calculated. x (n) The ratio of the 3dB width to the original signal pulse width.

6. The radar signal modulation type classification method based on pulse compression characteristics according to claim 5, characterized in that, In step 3, when the ratio is close to 1, the signal is a simple signal. For signals that do not meet the threshold, the real part re and the imaginary part im of x(n) are squared using the following formula to obtain the y(n) signal: y(n).re=(x(n).re) 2 y(n).im = (x(n).im) 2 Repeat steps 1 and 2 for y(n) to calculate the normalized result R of y(n). y (n) The ratio of the 3dB width to the original signal pulse width.

7. The radar signal modulation type classification method based on pulse compression characteristics according to claim 6, characterized in that, In step 4, when the ratio is close to 1, the signal is a binary phase-coded signal. The signal that does not meet the threshold is then subjected to a fourth power operation to obtain the z(n) signal: z(n).re = (x(n).re) 4 z(n).im = (x(n).im) 4 Repeat steps 1 and 2 for z(n) to calculate the normalized result R of z(n). z (n) The ratio of 3dB width to the original signal pulse width; When the ratio is greater than or equal to 1, the signal is a four-phase coded signal; signals that do not meet the threshold are other compressed signals.

8. The radar signal modulation type classification method based on pulse compression characteristics according to claim 2, characterized in that, In step 5, different delay coefficients a1 and a2 are selected, where 0.5 < a1 < 1 and 0 < a2 < 0.

5. Delay autocorrelation is performed to calculate the modulation slopes k1 and k2 respectively. When k1 = k2, the signal is a linear frequency modulation signal; otherwise, it is a nonlinear frequency modulation signal.

9. A radar signal modulation type classification system based on pulse compression characteristics, said system being based on the method of any one of claims 1-8, characterized in that, Includes the following modules: The autocorrelation-logarithmic normalization module performs autocorrelation calculations on the radar IQ signal, solves for its maximum value, and performs logarithmic normalization on the autocorrelation result based on the maximum value. The simple signal separation module detects the 3dB main lobe width of the normalized result and calculates the ratio of the main lobe width to the original signal pulse width. If the ratio is close to 1, the signal is determined to be a simple signal; otherwise, it is a pulse compression signal. The binary coded signal separation module performs squaring operations on the I and Q paths of the IQ signal respectively, repeating the steps used by the autocorrelation logarithm normalization module and the simple signal separation module. If the ratio is close to 1, it is determined to be a binary coded signal. The four-phase coded signal separation module performs a fourth-power operation on the I and Q paths of the IQ signal respectively. The steps used by the autocorrelation logarithm normalization module and the simple signal separation module are as follows: if the ratio is close to 1, it is determined to be a four-phase coded signal. The linear frequency modulation (LFM) signal and nonlinear frequency modulation (NFM) signal separation module performs time-delay autocorrelation calculations on the remaining unclassified signals using different time-delay correlation coefficients, calculates their modulation slopes separately, and determines whether a signal is a LFM signal based on whether the modulation slopes are the same.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements a radar signal modulation type classification method based on pulse compression characteristics as described in any one of claims 1-8.

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