DOA estimation method based on single differential pressure type vector hydrophone

Abstract

According to the DOA estimation method based on the single pressure difference type vector hydrophone, the sound pressure signal and the vibration velocity signal of the sound source are obtained through the single pressure difference type vector hydrophone, so that the energy envelopes of the sound pressure signal and the vibration velocity signal are obtained; according to the algorithm, a stable signal energy interval most suitable for incoming wave direction estimation in received signals can be searched from the angle of copying related energy envelopes, the energy of the whole received signals is utilized as much as possible, and the signal energy utilization rate of the algorithm is improved. In addition, on the basis of calculating cross-spectrum real parts among the channels, coherent demodulation values are generated by introducing the advantage of a processing mode of threshold judgment in communication signal processing on phase noise suppression, and the defect that a traditional vector DOA method is sensitive to phase noise is overcome. According to the method, the vector amplitude ratio of the vector channel is directly calculated through the observation equation, and the influence of environmental noise on the incoming wave direction estimation is further inhibited.

Description

Technical Field

[0001] The present invention belongs to the field of underwater acoustic positioning, and particularly relates to a DOA estimation method based on a single differential pressure vector hydrophone. Background Art

[0002] Underwater acoustic positioning plays a crucial role in fields such as underwater moving target navigation and deep-sea oil and gas development. Currently, the underwater acoustic positioning devices that have been put into large-scale use are: long baseline positioning system, short baseline positioning system, and ultra-short baseline positioning system. For small platforms that require underwater cluster collaboration, such as AUV (Autonomous Underwater Vehicle) and UUV (Unmanned Underwater Vehicle), these underwater acoustic positioning devices all have more or less problems of being too large in volume, too heavy in weight, and difficult to deploy. However, with the continuous development of the vector hydrophone theory, especially the continuous development of the differential pressure vector hydrophone, a single differential pressure vector hydrophone with a smaller aperture and lighter weight can perform DOA (Direction of Arrival) estimation and can be easily installed on small underwater platforms.

[0003] In the prior art, due to the manufacturing process of the single differential pressure vector hydrophone, the directivity concave point of the single differential pressure vector hydrophone is not deep enough, and there are phase characteristic inconsistencies in each processing channel in the subsequent signal processing circuit of the single differential pressure vector hydrophone. Therefore, there are inevitably errors when using the single differential pressure vector hydrophone for DOA estimation; the traditional average sound intensity algorithm and complex sound intensity algorithm do not consider these estimation errors, so the requirement of high-precision positioning of the target cannot be met when performing DOA estimation. Summary of the Invention

[0004] In order to solve the problem that in the prior art, due to errors, high-precision positioning of the target cannot be achieved when using a single differential pressure vector hydrophone for direction-of-arrival estimation, a DOA estimation method based on a single differential pressure vector hydrophone is proposed.

[0005] Step 1: Obtain multiple original sound pressure signals emitted by the sound source through a single differential pressure vector hydrophone, obtain the sound pressure signal, X-direction vibration velocity signal, and Y-direction vibration velocity signal at the receiving point according to the multiple original sound pressure signals, and preprocess the sound pressure signal, X-direction vibration velocity signal, and Y-direction vibration velocity signal;

[0006] Step 2: Respectively perform copy correlation on the preprocessed sound pressure signal, the processed X-direction vibration velocity signal, and the processed Y-direction vibration velocity signal with a known local reference signal to obtain a sound pressure signal copy correlation waveform, an X-direction vibration velocity signal copy correlation waveform, and a Y-direction vibration velocity signal copy correlation waveform; Perform cross-spectrum on the sound pressure signal copy correlation waveform with the X-direction vibration velocity signal copy correlation waveform and the Y-direction vibration velocity signal copy correlation waveform respectively to obtain coherent demodulation values X PSD and Y PSD ;

[0007] Step 3: Perform Hilbert transform on the copied relevant waveforms of the sound pressure signal, the copied relevant waveforms of the X-direction vibration velocity signal, and the copied relevant waveforms of the Y-direction vibration velocity signal respectively to obtain the energy envelope of the sound pressure signal, the energy envelope of the X-direction vibration velocity signal, and the energy envelope of the Y-direction vibration velocity signal; perform secondary threshold detection and discrete sampling on the energy envelope of the X-direction vibration velocity signal and the energy envelope of the Y-direction vibration velocity signal respectively to obtain the discrete sampling sequence of the X-direction vibration velocity signal and the discrete sampling sequence of the Y-direction vibration velocity signal;

[0008] Step 4: Obtain the peak positions Position_x of the discrete sampling sequence of the X-direction vibration velocity signal and the peak position Position_y of the discrete sampling sequence of the Y-direction vibration velocity signal, and calculate the ratio σ of the energy envelope value of the Y-direction vibration velocity signal at the Position_x position to the energy envelope value of the X-direction vibration velocity signal at the Position_x position x ; calculate the ratio σ of the energy envelope value of the Y-direction vibration velocity signal at the Position_y position to the energy envelope value of the X-direction vibration velocity signal at the Position_y position y ;

[0009] Step 5: Determine whether the ratio σ x or the ratio σ y meets the set conditions. If so, intercept the energy envelope of the X-direction vibration velocity signal and the energy envelope of the Y-direction vibration velocity signal, and calculate the estimated value of the incoming wave azimuth according to the intercepted energy envelope of the X-direction vibration velocity signal, the intercepted energy envelope of the Y-direction vibration velocity signal, the coherent demodulation value X PSD and Y PSD through the observation equation. If not, calculate the estimated value of the incoming wave azimuth according to the discrete sampling sequence of the X-direction vibration velocity signal, the discrete sampling sequence of the Y-direction vibration velocity signal, the coherent demodulation value X PSD and Y PSD through the observation equation; the observation equation is

[0010] where is the estimated value of the incoming wave azimuth, is the energy envelope of the Y-direction vibration velocity signal, is the energy envelope of the X-direction vibration velocity signal, N is the half window length, win vy is the window for intercepting the energy envelope of the Y-direction vibration velocity signal, win vx is the window for intercepting the energy envelope of the X-direction vibration velocity signal, and M is the number of points within the intercept window.

[0011] Beneficial effects

[0012] A DOA estimation method based on a single differential pressure vector hydrophone of the present invention, based on the system gain brought by the optimal estimation method - the copy correlation method under the maximum signal-to-noise ratio criterion, decomposes the incoming wave direction (DOA) process of the single differential pressure vector hydrophone into two parts: copy correlation energy envelope calculation and coherent demodulation value calculation. Since it is not necessary to consider the waveform distortion caused by phase noise, the algorithm can find the stable signal energy interval in the received signal that is most suitable for DOA estimation from the perspective of the copy correlation energy envelope, making the most of the energy of the entire received signal and improving the signal energy utilization rate of the algorithm. Since this method screens the received signals at the pointing dimple, and judges whether to intercept the energy envelopes of the X-direction vibration velocity signal and the Y-direction vibration velocity signal according to the ratio σ x and the ratio σ y , it suppresses the estimation error caused by the manufacturing process problems of the differential pressure vector hydrophone. The present invention also generates coherent demodulation values by introducing the processing method of threshold decision in communication signal processing based on calculating the real part of the cross-spectrum between channels, overcoming the disadvantage that the traditional vector DOA method is sensitive to phase noise. This makes it possible to perform robust DOA estimation without left-right ambiguity using the stable signal envelope energy. The present invention directly calculates the vector amplitude ratio of the vector channels through the observation equation, further suppressing the influence of environmental noise on DOA estimation. In summary, the present invention can obtain more robust and reliable time-domain DOA results in the incoming wave direction estimation of the single differential pressure vector hydrophone. Description of the Drawings

[0013] Figure 1 Is the incoming wave direction estimation result of the anechoic tank based on the average sound intensity meter in the specific embodiment of this application;

[0014] Figure 2 Is the incoming wave direction estimation result of the anechoic tank of the incoming wave direction estimation method based on the single differential pressure vector hydrophone in the specific embodiment of this application. Detailed Embodiments

[0015] Detailed Embodiment 1: The following will combine the attached drawings in the embodiments of the present invention Figure 1 to the attached Figure 2 , and describe this embodiment, clearly and completely describing the technical solutions in the embodiments of the present invention:

[0016] Let r be the radius of the single differential pressure vector hydrophone, k be the wave number of the cooperative signal. For the differential pressure vector hydrophone satisfying kr << 1, let the waveform of the sound source signal be s(t), satisfying the far-field condition, and the system sampling rate be Fs;

[0017] A DOA estimation method based on a single differential pressure vector hydrophone includes:

[0018] Step 1: Obtain multiple original sound pressure signals emitted by the sound source through a single differential pressure vector hydrophone. Based on the multiple original sound pressure signals emitted by the sound source, obtain the sound pressure signal, the X-direction particle velocity signal, and the Y-direction particle velocity signal, and preprocess the sound pressure signal, the X-direction particle velocity signal, and the Y-direction particle velocity signal;

[0019] Specifically, obtain the sound pressure, the X-direction particle velocity, and the Y-direction particle velocity of the sound source radiation signal at the receiving point through a single differential pressure vector hydrophone, and preprocess the three-channel LFM signals;

[0020] Step 2: Respectively perform copy correlation on the preprocessed sound pressure signal, the processed X-direction particle velocity signal, and the processed Y-direction particle velocity signal with a known local reference signal to obtain the copy correlation waveform of the sound pressure signal, the copy correlation waveform of the X-direction particle velocity signal, and the copy correlation waveform of the Y-direction particle velocity signal; Perform cross-spectrum on the copy correlation waveform of the sound pressure signal with the copy correlation waveforms of the X-direction particle velocity signal and the Y-direction particle velocity signal respectively to obtain the coherent demodulation values X PSD and Y PSD ;

[0021] Specifically, calculate the cross-spectrum of the sound pressure channel and the signals of the two particle velocity channels respectively, and obtain the coherent demodulation values accordingly for subsequent judgment of the quadrant where the azimuth of the target incoming wave is located;

[0022] Step 3: Respectively perform Hilbert transform on the copy correlation waveform of the sound pressure signal, the copy correlation waveform of the X-direction particle velocity signal, and the copy correlation waveform of the Y-direction particle velocity signal to obtain the energy envelope of the sound pressure signal, the energy envelope of the X-direction particle velocity signal, and the energy envelope of the Y-direction particle velocity signal; Perform secondary threshold detection and discrete sampling on the energy envelopes of the X-direction particle velocity signal and the Y-direction particle velocity signal respectively to obtain the discrete sampling sequence of the X-direction particle velocity signal and the discrete sampling sequence of the Y-direction particle velocity signal;

[0023] Step 4: Obtain the peak position Position_x of the discrete sampling sequence of the X-direction particle velocity signal and the peak position Position_y of the discrete sampling sequence of the Y-direction particle velocity signal, and calculate the ratio σ x of the energy envelope value of the Y-direction particle velocity signal at the Position_x position to the energy envelope value of the X-direction particle velocity signal at the Position_x position; Calculate the ratio σ y of the energy envelope value of the Y-direction particle velocity signal at the Position_y position to the energy envelope value of the X-direction particle velocity signal at the Position_y position;

[0024] Specifically, calculate the threshold of the secondary threshold detection according to the situations of the sound pressure signal, the X-direction particle velocity signal, and the Y-direction particle velocity signal, and intercept the interval near the first peak where the envelope energy of the copy correlation waveform exceeds the threshold according to this threshold.

[0025] Step 5: Judge the ratio σ x or the ratio σy Whether the set conditions are met. If so, intercept the energy envelope of the X - direction vibration velocity signal and the energy envelope of the Y - direction vibration velocity signal. Based on the intercepted energy envelope of the X - direction vibration velocity signal, the intercepted energy envelope of the Y - direction vibration velocity signal, and the coherent demodulation values X PSD and Y PSD Calculate the estimated value of the incoming wave azimuth through the observation equation. Otherwise, based on the discrete sampling sequence of the X - direction vibration velocity signal, the discrete sampling sequence of the Y - direction vibration velocity signal, and the coherent demodulation values X PSD and Y PSD Calculate the estimated value of the incoming wave azimuth through the observation equation; the observation equation is

[0026] where is the estimated value of the incoming wave azimuth, is the energy envelope of the Y - direction vibration velocity signal, is the energy envelope of the X - direction vibration velocity signal, N is the half - window length, win vy is the window for intercepting the energy envelope of the Y - direction vibration velocity signal, win vx is the window for intercepting the energy envelope of the X - direction vibration velocity signal, and M is the number of points within the intercept window.

[0027] Specifically, for the data where the incoming wave azimuth is near the directivity pit of the vibration velocity channel, perform the directivity pit noise suppression of the vector hydrophone to correct the discrete sampling sequences of the X - direction vibration velocity signal and the Y - direction vibration velocity signal obtained by discrete sampling in step three.

[0028] Judge whether the ratio σ x or the ratio σ y meets the set conditions. The method is as follows: Determine the directivity pit suppression interval according to the depth of the directivity pit of the vector hydrophone, take 5° to 10° on each side of each theoretical pit point and calculate the modulus of the arctangent value corresponding to the interval endpoints; Define the smaller of the two obtained arctangent value moduli as the first set value and the larger one as the second set value;

[0029] Judge whether the ratio σ x or the ratio σ y is less than or equal to the first set value. If so, the ratio σ x or the ratio σ y meets the set conditions; If neither the ratio σ x nor the ratio σ y is less than or equal to the first set value, then judge whether the ratio σ x or the ratio σ y is greater than the second set value. If so, it meets the set conditions.

[0030] Determine the directivity pit suppression interval according to the depth of the directivity pit of the vector hydrophone. When taking 5° on each side of each theoretical pit and calculating the modulus of the arctangent value corresponding to the interval endpoints; the first set value is 0.1763, and the second set value is 5.6713;

[0031] Furthermore, obtain the sound pressure signal, X-direction particle velocity signal, and Y-direction particle velocity signal from the multiple original sound pressure signals emitted by the sound source, including:

[0032] Obtain the sound pressure signal P(t) by taking the average of the multiple original sound pressure signals of the sound source;

[0033]

[0034] X-direction particle velocity signal

[0035] Y-direction particle velocity signal

[0036] Among them, v1(t), v2(t), v3(t), and v4(t) are the four original sound pressure signals respectively, Im(·) represents the imaginary part in the complex number, τ is the integration time delay, and t is the absolute time.

[0037] s(t) is the waveform of the sound source signal received by the single differential pressure type vector hydrophone, and are the phase differences corresponding to the differential pressure hydrophone channels respectively.

[0038] It is known that the numerical value of the sound pressure signal P(t) of the reference signal is equal to that of the sound source signal.

[0039] Furthermore, preprocess the sound pressure signal, X-direction particle velocity signal, and Y-direction particle velocity signal, including:

[0040] Synchronize the sound pressure signal P(t), X-direction particle velocity signal Vx(t), and Y-direction particle velocity signal Vy(t) through the windowed copy correlation method to obtain the synchronized sound pressure signal, synchronized X-direction particle velocity signal, and synchronized Y-direction particle velocity signal;

[0041] Set a fixed number of signal time periods in front of the maximum value of the correlation peak as the noise sampling interval, and intercept the synchronized sound pressure signal, synchronized X-direction particle velocity signal, and synchronized Y-direction particle velocity signal according to the noise sampling interval to obtain the intercepted sound pressure signal, intercepted X-direction particle velocity signal, and intercepted Y-direction particle velocity signal;

[0042] Perform band-pass filtering on the intercepted sound pressure signal, intercepted X-direction particle velocity signal, and intercepted Y-direction particle velocity signal respectively to obtain the processed sound pressure signal, processed X-direction particle velocity signal, and processed Y-direction particle velocity signal.

[0043] Further, the cross-spectrum of the copy-correlated waveform of the sound pressure signal is respectively calculated with the copy-correlated waveforms of the X-direction vibration velocity signal and the Y-direction vibration velocity signal to obtain the coherent demodulation values X PSD and Y PSD , including:

[0044] The copy-correlated waveform R sp (t) of the sound pressure signal is respectively cross-spectrally calculated with the copy-correlated waveform R svx (t) of the X-direction vibration velocity signal and the copy-correlated waveform R svy (t) of the Y-direction vibration velocity signal to obtain the actual value of the real part of the cross-spectrum at the maximum absolute value of the real part of the cross-spectrum, which is X PSDmax and Y PSDmax ;

[0045] Perform threshold judgment on X PSDmax and Y PSDmax . The threshold is set to zero. The judgment result greater than zero is +1, and the judgment result less than zero is -1 to obtain the coherent demodulation values X PSDmax and Y PSDmax corresponding to X PSD and Y PSD .

[0046] Further, perform secondary threshold detection and discrete sampling on the energy envelopes of the X-direction vibration velocity signal and the Y-direction vibration velocity signal respectively to obtain the discrete sampling sequences of the X-direction vibration velocity signal and the Y-direction vibration velocity signal, including:

[0047] Set the first 80% of the noise sampling interval as the noise calculation interval, and calculate the maximum values M and M of the energy envelopes of the copy-correlated waveforms of the X-direction vibration velocity signal and the Y-direction vibration velocity signal respectively in the noise calculation interval svx and M svy . Multiply the maximum values M svx and M svy by a set multiple respectively to obtain the first threshold value and the second threshold value . In this embodiment, the set multiple ranges from 5 to 10 times;

[0048] According to the first threshold value and the second threshold value , perform secondary threshold detection on the energy envelopes of the copy-correlated waveforms of the X-direction vibration velocity signal and the Y-direction vibration velocity signal respectively; Intercept the energy envelope of the copy-correlated waveform of the X-direction vibration velocity signal above the first threshold value The discrete sampling sequence of the energy envelope of the cross-correlation waveform of the X-direction vibration velocity signal is obtained by taking m points on each side of the first peak. The energy envelope of the cross-correlation waveform of the Y-direction vibration velocity signal is intercepted. Exceed the second threshold value. The discrete sampling sequence of the energy envelope of the cross-correlation waveform of the Y-direction vibration velocity signal is obtained by taking m points on each side of the first peak.

[0049] where m is an integer, win vx-z is the interception window of the energy envelope of the cross-correlation waveform of the X-direction vibration velocity signal, and win vy-z is the interception window of the energy envelope of the cross-correlation waveform of the Y-direction vibration velocity signal;

[0050] In this specific embodiment, the value range of m is determined according to the half window length of the main peak corresponding to the -3dB of the intercepted peak.

[0051] Specifically, in this embodiment, 1215 sampling points in front of the maximum value of the correlation peak are taken as the noise interval.

[0052] Furthermore, according to the ratio σ x and the ratio σ y it is judged whether to intercept the energy envelope of the X-direction vibration velocity signal and the energy envelope of the Y-direction vibration velocity signal; if so, the estimated value of the incoming wave azimuth is calculated through the observation equation according to the intercepted energy envelope of the X-direction vibration velocity signal, the energy envelope of the Y-direction vibration velocity signal, the coherent demodulation values X PSD and Y PSD If not, the estimated value of the incoming wave azimuth is calculated through the observation equation according to the discrete sampling sequence of the X-direction vibration velocity signal, the discrete sampling sequence of the Y-direction vibration velocity signal, the coherent demodulation values X PSD and Y PSD including:

[0053] i is the position in the discrete sampling sequence;

[0054] Judge whether the ratio σ x or the ratio σ y is less than or equal to the first set value. If so, the energy envelope of the cross-correlation waveform of the X-direction vibration velocity signal is re-intercepted with Position_x as the interception center and n as the half window length and the energy envelope of the cross-correlation waveform of the Y-direction vibration velocity signal The estimated value of the incoming wave azimuth is calculated through the observation equation according to the intercepted energy envelope of the X-direction vibration velocity signal, the energy envelope of the Y-direction vibration velocity signal, the coherent demodulation values X PSD and Y PSD ;

[0055] where is the estimated value of the incoming wave azimuth, is the energy envelope of the Y-direction vibration velocity signal, is the energy envelope of the X-direction vibration velocity signal, win vy-x is the energy envelope intercept window of the Y-direction vibration velocity signal re-intercepted with Position_x as the intercept center and n as the half window length, win vx-x is the energy envelope intercept window of the X-direction vibration velocity signal re-intercepted with Position_x as the intercept center and n as the half window length, j is the point within the intercept window, j ∈ 2n + 1, n = m.

[0056] If the ratio σ x or the ratio σ y is not less than or equal to the first set value, then it is judged whether the ratio σ x or the ratio σ y is greater than the second set value. If so, re-intercept the energy envelope of the X-direction vibration velocity signal copy-related waveform with Position_y as the intercept center and n as the half window length and the energy envelope of the Y-direction vibration velocity signal copy-related waveform According to the intercepted energy envelope of the X-direction vibration velocity signal, the energy envelope of the Y-direction vibration velocity signal, the coherent demodulation value X PSD and Y PSD Calculate the estimated value of the incoming wave azimuth through the observation equation;

[0057] win vy-y is the energy envelope intercept window of the Y-direction vibration velocity signal re-intercepted with Position_y as the intercept center and n as the half window length, win vx-y is the energy envelope intercept window of the X-direction vibration velocity signal re-intercepted with Position_y as the intercept center and n as the half window length, j is the point within the intercept window;

[0058] If the ratio σ x or the ratio σ y is not greater than the second set value, then according to the discrete sampling sequence of the X-direction vibration velocity signal, the coherent demodulation value X of the discrete sampling sequence of the Y-direction vibration velocity signal PSD and Y PSD Calculate the estimated value of the incoming wave azimuth through the observation equation;

[0059] where win vy-z is the energy envelope sampling window of the Y-direction vibration velocity signal, win vx-z is the energy envelope sampling window of the X-direction vibration velocity signal, m is the discrete sampling half window length, and p is the point within the sampling window.

[0060] Embodiment 2: A computer-readable storage medium stores a computer program. When the computer program is read and run by a processor, it implements the DOA estimation method based on a single differential pressure vector hydrophone as described in Embodiment 1.

[0061] Embodiment 3: A computer device includes a memory, a processor, and a computer program stored on the memory and executable on the processor. It is characterized in that when the processor executes the computer program, it implements the steps of the DOA estimation method based on a single differential pressure vector hydrophone as described in Embodiment 1. Specific embodiment:

[0063] Experimental conditions: The sound source radiates a broadband LFM signal from 20 kHz to 29 kHz. The receiving end is a single differential pressure vector hydrophone. The sound source and the hydrophone are placed in an anechoic water tank, and the sound field placement satisfies the far-field condition. The signal-to-noise ratio is 9 dB to 12 dB.

[0064] Keep the positions of the fixed transmitting transducer and the receiving differential pressure vector hydrophone unchanged. Rotate the receiving differential pressure vector hydrophone at regular intervals, and record the signals at the same time. Repeat recording multiple groups of data at the same angle after each rotation. At the same time, use the average sound intensity method and this method to estimate the DOA of a single vector hydrophone. The DOA results in the anechoic water tank based on the average sound intensity method are as Figure 1 shown, and the DOA results in the anechoic water tank by the incoming wave azimuth estimation method based on a single differential pressure vector hydrophone of this application are as Figure 2 shown.

[0065] By comparing the two DOA results with the true value and referring to the fluctuations of the two DOA results respectively, it can be seen that the calculation result of the incoming wave azimuth estimation method based on a single differential pressure vector hydrophone proposed by the present invention is more robust and reliable than the traditional average sound intensity method of a single vector hydrophone, and the error is also smaller.

[0066] Although the present invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed, as long as they do not deviate from the spirit and scope of the present invention as defined by the appended claims. It should be understood that different dependent claims and the features described herein can be combined in a manner different from that described in the original claims. It should also be understood that the features described in connection with a single embodiment can be used in other described embodiments.

Claims

1. A DOA estimation method based on a single pressure difference vector hydrophone, characterized in that: include: Step 1: obtaining a multi-channel original sound pressure signal emitted by a sound source through a single pressure difference vector hydrophone, obtaining a sound pressure signal, an X-direction vibration velocity signal, and a Y-direction vibration velocity signal according to the multi-channel original sound pressure signal emitted by the sound source, and preprocessing the sound pressure signal, the X-direction vibration velocity signal, and the Y-direction vibration velocity signal; Step 2: perform copy correlation on the preprocessed sound pressure signal, the processed X-direction vibration velocity signal and the processed Y-direction vibration velocity signal with the known local reference signal to obtain the sound pressure signal copy correlation waveform, the X-direction vibration velocity signal copy correlation waveform and the Y-direction vibration velocity signal copy correlation waveform; perform cross-spectral analysis on the sound pressure signal copy correlation waveform with the X-direction vibration velocity signal copy correlation waveform and the Y-direction vibration velocity signal copy correlation waveform to obtain the coherent demodulation value X PSD and Y PSD ; Step 3: Perform Hilbert transform on the waveform related to the copy of the sound pressure signal, the waveform related to the copy of the X-direction vibration velocity signal, and the waveform related to the copy of the Y-direction vibration velocity signal to obtain the energy envelope of the sound pressure signal, the energy envelope of the X-direction vibration velocity signal, and the energy envelope of the Y-direction vibration velocity signal; perform secondary threshold detection and discrete sampling on the energy envelope of the X-direction vibration velocity signal and the energy envelope of the Y-direction vibration velocity signal to obtain a discrete sampling sequence of the X-direction vibration velocity signal and a discrete sampling sequence of the Y-direction vibration velocity signal; Step 4: Obtain the peak position Position_x of the discrete sampling sequence of the X-direction vibration velocity signal and the peak position Position_y of the discrete sampling sequence of the Y-direction vibration velocity signal, and calculate the ratio σ of the energy envelope value of the Y-direction vibration velocity signal at Position_x to the energy envelope value of the X-direction vibration velocity signal at Position_x x ; Calculate the ratio σ of the energy envelope value of the Y-axis vibration velocity signal at Position_y and the energy envelope value of the X-axis vibration velocity signal at Position_y y ; Step 5: Determine the ratio σ x Or the ratio σ y Whether the set conditions are met, if so, intercept the energy envelope of the X-direction vibration velocity signal and the energy envelope of the Y-direction vibration velocity signal, and according to the intercepted energy envelope of the X-direction vibration velocity signal, the intercepted energy envelope of the Y-direction vibration velocity signal, and the coherent demodulation value X PSD and Y PSD The estimated value of the incoming wave direction is calculated by the observation equation. If not, the coherent demodulation value X is obtained according to the discrete sampling sequence of the X-direction velocity signal and the discrete sampling sequence of the Y-direction velocity signal. PSD and Y PSD The estimated value of the incoming wave direction is calculated by the observation equation; the observation equation is in is the estimated value of the incoming wave direction, is the energy envelope of the Y-axis vibration velocity signal, is the energy envelope of the X-axis velocity signal, N is the half window length, win vy is the energy envelope interception window of the Y-axis vibration velocity signal, win vx is the interception window of the energy envelope of the X-axis velocity signal, and M is the point in the interception window.

2. The DOA estimation method based on single pressure difference vector hydrophone according to claim 1, characterized in that: The sound pressure signal, the X-axis vibration velocity signal and the Y-axis vibration velocity signal are obtained according to the multi-channel original sound pressure signals emitted by the sound source, including: The sound pressure signal P(t) is obtained by averaging the multiple original sound pressure signals of the sound source; X-axis vibration velocity signal Y-axis vibration velocity signal Among them, v1(t), v2(t), v3(t) and v4(t) are four original sound pressure signals, Im(·) represents the imaginary part of the complex number, τ is the integration delay, and t is the absolute time.

3. The DOA estimation method based on single pressure difference vector hydrophone according to claim 2, characterized in that: Preprocess the sound pressure signal, X-axis vibration velocity signal and Y-axis vibration velocity signal, including: The sound pressure signal P(t), the X-direction vibration velocity signal Vx(t) and the Y-direction vibration velocity signal Vy(t) are synchronized by a windowed copy correlation method to obtain a synchronized sound pressure signal, a synchronized X-direction vibration velocity signal and a synchronized Y-direction vibration velocity signal; A fixed number of signal time periods in front of the maximum value of the correlation peak are set as the noise sampling interval, and the synchronized sound pressure signal, the synchronized X-direction vibration velocity signal and the synchronized Y-direction vibration velocity signal are intercepted according to the noise sampling interval to obtain the intercepted sound pressure signal, the intercepted X-direction vibration velocity signal and the intercepted Y-direction vibration velocity signal; The intercepted sound pressure signal, the intercepted X-direction vibration velocity signal and the intercepted Y-direction vibration velocity signal are respectively subjected to bandpass filtering to obtain a processed sound pressure signal, a processed X-direction vibration velocity signal and a processed Y-direction vibration velocity signal.

4. The DOA estimation method based on single pressure difference vector hydrophone according to claim 3 is characterized by: The sound pressure signal copy related waveform is cross-spectrally analyzed with the X-direction vibration velocity signal copy related waveform and the Y-direction vibration velocity signal copy related waveform to obtain the coherent demodulation value X PSD and Y PSD ,include: Copy the sound pressure signal to the relevant waveform R sp (t) Correlation waveform R with X-axis velocity signal copy svx (t) and the Y-axis velocity signal copy related waveform R svy (t) Perform cross-spectrum to obtain the actual value X of the real part of the cross-spectrum where the absolute value of the real part of the cross-spectrum is the largest PSDmax and Y PSDmax ; X PSDmax and Y PSDmax Make a threshold decision, set the threshold to zero, the decision greater than zero is +1, and the decision less than zero is -1. PSDmax and Y PSDmax The corresponding coherent demodulation value X PSD and Y PSD .

5. The DOA estimation method based on single pressure difference vector hydrophone according to claim 4, characterized in that: The energy envelope of the X-direction vibration velocity signal and the energy envelope of the Y-direction vibration velocity signal are respectively subjected to secondary threshold detection and discrete sampling to obtain a discrete sampling sequence of the X-direction vibration velocity signal and a discrete sampling sequence of the Y-direction vibration velocity signal, including: Set the set part of the noise sampling interval as the noise calculation interval, and calculate the energy envelope of the waveform related to the X-axis vibration velocity signal copy The energy envelope of the waveform related to the Y-axis velocity signal copy The maximum value M in the noise calculation interval svx and M svy , the maximum value M svx and M svy Expand the set multiples to get the first threshold value and the second threshold According to the first threshold and the second threshold Copy the relevant waveform energy envelope of the X-axis vibration velocity signal The energy envelope of the waveform related to the Y-axis velocity signal copy Perform secondary threshold detection; intercept the X-axis velocity signal and copy the relevant waveform energy envelope According to the first threshold The discrete sampling sequence of the energy envelope of the X-axis velocity signal Bayer-correlated waveform is obtained by taking m points on the left and right of the first peak of Intercept the Y-axis vibration velocity signal and copy the relevant waveform energy envelope Over the second threshold The discrete sampling sequence of the energy envelope of the Y-axis vibration velocity signal copy related waveform is obtained by taking m points on the left and right of the first peak of Among them, m is an integer and win is the capture window.

6. The DOA estimation method based on single pressure difference vector hydrophone according to claim 5, characterized in that: According to the ratio σ x and the ratio σ y Determine whether to intercept the energy envelope of the X-direction vibration velocity signal and the energy envelope of the Y-direction vibration velocity signal; if so, determine whether to intercept the energy envelope of the X-direction vibration velocity signal, the energy envelope of the Y-direction vibration velocity signal, the coherent demodulation value X PSD and Y PSD The estimated value of the incoming wave direction is calculated by the observation equation. If not, the coherent demodulation value X is obtained according to the discrete sampling sequence of the X-direction velocity signal and the discrete sampling sequence of the Y-direction velocity signal. PSD and Y PSD The estimated value of the incoming wave direction is calculated by the observation equation, include: i is the position in the discrete sampling sequence; Judgment ratio σ x Or the ratio σ y Is it less than or equal to the first set value? If so, take Position_x as the interception center and n as the half window length to re-intercept the X-axis velocity signal and copy the relevant waveform energy envelope The energy envelope of the waveform related to the Y-axis velocity signal copy According to the intercepted X-axis vibration velocity signal energy envelope, Y-axis vibration velocity signal energy envelope, coherent demodulation value X PSD and Y PSD Calculate the estimated value of the incoming wave direction through the observation equation; in is the estimated value of the incoming wave direction, is the energy envelope of the Y-axis vibration velocity signal, is the energy envelope of the X-axis vibration velocity signal, win vy-x is the interception window of the energy envelope of the Y-axis velocity signal re-intercepted with Position_x as the interception center and n as the half window length, win vx-x is the interception window of the energy envelope of the X-axis velocity signal re-intercepted with Position_x as the interception center, n is the half window length, j is the point in the interception window, j∈2n+1, n=m. If the ratio σ x Or the ratio σ y If both are not less than or equal to the first set value, the ratio σ is judged x Or the ratio σ y Is it greater than the second set value? If so, Position_y is the interception center, n is the half window length, and the X-axis velocity signal is re-intercepted to copy the relevant waveform energy envelope The energy envelope of the waveform related to the Y-axis velocity signal copy According to the intercepted X-axis vibration velocity signal energy envelope, Y-axis vibration velocity signal energy envelope, coherent demodulation value X PSD and Y PSD Calculate the estimated value of the incoming wave direction through the observation equation; win vy-y is the energy envelope interception window of the Y-axis velocity signal with Position_y as the interception center and n as the half window length, win vx-y is the interception window of the energy envelope of the X-axis velocity signal re-intercepted with Position_y as the interception center, n is the half window length, and j is the point in the interception window; If the ratio σ x Or the ratio σ y If both are not greater than the second set value, then the coherent demodulation value X is obtained according to the discrete sampling sequence of the X-direction vibration velocity signal and the discrete sampling sequence of the Y-direction vibration velocity signal. PSD and Y PSD Calculate the estimated value of the incoming wave direction through the observation equation; Among them win vy-z is the energy envelope sampling window of the Y-axis vibration velocity signal, win vx-z is the energy envelope sampling window of the X-axis velocity signal, m is the discrete sampling half-window length, and p is the point in the sampling window.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is read and executed by a processor, the DOA estimation method based on a single pressure difference vector hydrophone according to any one of claims 1 to 6 is implemented.

8. A computer 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 computer program, the steps of the DOA estimation method based on a single pressure difference vector hydrophone as claimed in any one of claims 1 to 6 are implemented.

Images