Target detection method and system based on deep-sea large-aperture vertical array

Abstract

The invention relates to the technical field of underwater acoustic engineering, ocean engineering and sonar, in particular to a target detection method and system based on a deep-sea large-aperture vertical array. The method comprises the following steps: step 1, receiving a time domain signal radiated by a target sound source through a large-aperture vertical array laid in deep sea in a bottom-supported manner; 2, performing fast Fourier transform on the time domain signals received by each array element to obtain corresponding signal frequency spectrums; 3, calculating a steering vector according to the phase difference of the depth of each array element of the large-aperture vertical array relative to the reference array element; and based on the steering vector, processing the signal spectrums of different array elements through a spatial power spectrum estimation method to obtain spatial power spectrum estimation results at different angles of arrival so as to realize detection of a target sound source.

Description

Technical Field

[0001] The present invention relates to the fields of underwater acoustic engineering, ocean engineering and sonar technology, and in particular to a target detection method and system based on a deep-sea large-aperture vertical array. Background Art

[0002] In deep-sea environments, bottom-mounted vertical arrays are a common formation for detecting and locating sound source targets. Leveraging the acoustic propagation characteristics of the direct sound zone, they enable comprehensive detection of sound source targets at medium and short ranges. As target sound source levels decrease and the number of interfering vessels increases, the required array aperture becomes larger. More receiving elements and a larger array aperture improve both beamforming gain and angular resolution, thereby enhancing interference suppression.

[0003] However, as the array aperture gradually increases, the performance of the spatial power spectrum estimation method based on the plane wave assumption is gradually limited. For vertical arrays with smaller apertures, under the far-field assumption, the differences in the arrival angles of the sound source target at different array elements can be ignored. For each array element, the sound source can be regarded as coming from the same arrival angle. For vertical arrays with larger apertures, when the far-field approximation does not hold in the deep-sea direct sound zone, the arrival angles of the sound source target relative to different array elements will differ. If the steering vector constructed based on the plane wave assumption is still used for spatial power spectrum estimation, the energy of the sound source will be dispersed within a certain width of the arrival angle range (from the arrival angle of the shallowest array element to the arrival angle of the deepest array element) in the spatial power spectrum estimation result, thereby reducing the detection ability of weak targets. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problem of degraded target detection performance of large-aperture vertical arrays based on the traditional far-field plane wave assumption, thereby providing a target detection method and system based on a deep-sea large-aperture vertical array, which uses the phase difference of each array element of the vertical array relative to a reference array element to construct a steering vector.

[0005] To solve the above technical problems, the technical solution of the present invention provides a target detection method based on a deep-sea large-aperture vertical array, comprising:

[0006] Step 1: Receive the time domain signal radiated by the target sound source through a large-aperture vertical array deployed on the bottom of the deep sea;

[0007] Step 2: Perform fast Fourier transform on the time domain signal received by each array element to obtain the corresponding signal spectrum;

[0008] Step 3: Calculate the steering vector based on the phase difference of the depth of each element of the large-aperture vertical array relative to the reference element. Based on the steering vector, process the signal spectra of different elements using the spatial power spectrum estimation method to obtain spatial power spectrum estimation results at different arrival angles to achieve detection of the target sound source.

[0009] As an improvement to the above method, the deployment depth of the large-aperture vertical array is 400-6000m, and the sea depth D of the deep sea ranges from 1000-6000m.

[0010] As an improvement to the above method, the depths of the elements of the large aperture vertical array are d1, ..., d m ,...,d M ; Where d1 is the depth of the first array element, d m is the depth of the mth array element, d M is the depth of the Mth array element; the total number of array elements of the large aperture vertical array is M, and the sampling rate of the large aperture vertical array is f s , the sampling rate f s The range is 100Hz~40kHz.

[0011] As an improvement to the above method, in step 2, the time domain signal received by the mth array element is subjected to fast Fourier transform to obtain the signal at frequency f. l The signal spectrum at x m (f l ); where l = 1, 2, ..., L, L is the number of frequency points used, f1 is the preset lower bound of the frequency range of the spatial power spectrum estimation during target detection, and f L The preset upper bound of the frequency range of the spatial power spectrum estimation for target detection.

[0012] As an improvement to the above method, the preset lower bound f1 of the target detection spatial power spectrum estimation frequency range is in the range of 0.1Hz to 3.5kHz, and the preset upper bound f1 of the target detection spatial power spectrum estimation frequency range is in the range of 0.1Hz to 3.5kHz. L The range is 5Hz~4kHz.

[0013] As an improvement of the above method, the spatial power spectrum estimation method includes: a conventional beamforming spatial power spectrum estimation method.

[0014] As an improvement to the above method, step 3 specifically includes:

[0015] Calculate at frequency f l And the angle θ k The beam output sound field B(θ k ):

[0016]

[0017] Where, the arrival angle θ k From -90° to 90°, the value is taken every 0.01° to 1°; A(θ k ,f l ) is the steering vector obtained by calculating the phase difference between the depth of each element of the large aperture vertical array and the reference element during beamforming, wherein the reference element is any element in the large aperture vertical array; X(f l ) is the target sound source radiation signal received by the large aperture vertical array at the frequency point f l The spectrum vector at the location; the superscript H represents the conjugate transpose operator; f1 is the preset lower bound of the frequency range of the spatial power spectrum estimation during target detection, f L is the preset upper bound of the frequency range of the spatial power spectrum estimation during target detection;

[0018]

[0019] Where, for an arrival angle θ greater than zero degrees k , propagation path length r m (θ k )for:

[0020]

[0021] Among them, d ref is the depth of the reference element, d m is the depth of the mth array element;

[0022] For an arrival angle θ equal to zero degrees k , propagation path length r m (θ k )for:

[0023] r m (θ k )=d m

[0024] For an arrival angle θ less than zero degrees k , propagation path length r m (θ k )for:

[0025]

[0026] Where D is the ocean depth; c is the seawater sound speed at the center of the receiving array.

[0027] As an improvement to the above method, the reference array element is an array element at the center of a large aperture vertical array.

[0028] As an improvement to the above method, the target sound source radiation signal received by the large aperture vertical array is at the frequency point f l The spectrum vector X(f l )for:

[0029] X(f l )=[x1(f l ),x2(f l ),...,x m (f l ),...,x M (f l )] T

[0030] Among them, x1(f l ) is the first array element at frequency f l The signal spectrum at x2(f l ) is the second array element at frequency f l The signal spectrum at x m (f l ) is the mth array element at frequency f l The signal spectrum at x M (f l ) is the Mth array element at frequency f l The signal spectrum at ; the total number of array elements of the large aperture vertical array is M; the superscript T represents the transpose operator.

[0031] To achieve another object of the present invention, the present invention further provides a target detection system based on a deep-sea large-aperture vertical array, comprising:

[0032] A large-aperture vertical array, deployed on the bottom of the deep sea, is used to receive time-domain signals radiated by target sound sources;

[0033] A fast Fourier transform module, used to perform fast Fourier transform on the time domain signal received by each array element to obtain the corresponding signal spectrum; and

[0034] The estimation module is used to calculate the steering vector based on the phase difference of the depth of each element of the large-aperture vertical array relative to the reference element; based on the steering vector, it is used to process the signal spectra of different elements using the spatial power spectrum estimation method to obtain spatial power spectrum estimation results at different arrival angles to achieve detection of the target sound source.

[0035] Compared to existing technologies, the present invention proposes a target detection method and system based on a deep-sea large-aperture vertical array. The system is configured as a large-aperture vertical acoustic array deployed near the seafloor. The present invention deploys the large-aperture vertical array near the seafloor to receive time-domain signals radiated by target sound sources. The target sound source is detected through processing such as fast Fourier transforms, steering vector calculation, and spatial power spectrum estimation. The present invention uses a specific element of the vertical array as a phase reference point. Based on the assumption of constant sound velocity at sea depth, the steering vector is calculated using geometric relationships. This solves the problem of degraded target detection performance caused by the different arrival angles of the sound source at different elements in the vertical array, as observed in traditional spatial power spectrum estimation methods based on the plane wave assumption. The present invention uses a specific element of the vertical array as the phase reference point. This method ignores the differences in sound velocity at different depths in the seawater. Based on the assumption that the sound velocity of deep-sea water from the surface to the seafloor is constant, the method uses geometric relationships to calculate the phase differences of other elements in the vertical array relative to the reference element. Based on this phase difference, the corresponding steering vector is constructed, thereby solving the problem of different arrival angles of the sound source at different elements and improving target detection performance. In addition, since a certain array element is selected as the reference array element to construct the steering vector, the target detection method and system proposed in the present invention retain the channel response from the target sound source to the reference array element. Therefore, the target detection method and system proposed in the present invention can also be further used for subsequent target position and ocean environment parameter inversion and other related work. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The seawater sound velocity profile and vertical array deployment depth used in the simulation experiment of the present invention;

[0037] Figure 2(a) shows the motion trajectory of the sound source in the simulation experiment of the present invention;

[0038] Figure 2(b) shows the sound source transmission and reception distance in the simulation experiment of the present invention;

[0039] Figure 3(a) shows the spatial power spectrum estimation results obtained by conventional beamforming of the target sound source at all times of the simulation experiment under medium and high signal-to-noise ratio based on the plane wave assumption;

[0040] FIG3( b ) shows the spatial power spectrum estimation results obtained by conventional beamforming of the target sound source at all times of the simulation experiment at medium and high signal-to-noise ratios based on the method provided by the present invention;

[0041] Figure 4(a) shows the spatial power spectrum estimation results obtained by conventional beamforming of the target sound source at all times of the simulation experiment under low and medium signal-to-noise ratios based on the plane wave assumption;

[0042] FIG4( b ) shows the spatial power spectrum estimation results obtained by conventional beamforming of the target sound source at all moments of the simulation experiment at low and medium signal-to-noise ratios based on the method provided by the present invention;

[0043] Figure 5This is a flow chart of the target detection method based on deep-sea large-aperture vertical array provided by the present invention. DETAILED DESCRIPTION

[0044] The technical solution provided by the present invention is further illustrated below with reference to embodiments.

[0045] Example 1

[0046] This embodiment provides a target detection method based on a deep-sea large-aperture vertical array, including:

[0047] Step 1: Receive the time domain signal radiated by the target sound source through a large-aperture vertical array deployed on the bottom of the deep sea;

[0048] Step 2: Perform fast Fourier transform on the time domain signal received by each array element to obtain the corresponding signal spectrum;

[0049] Step 3: Calculate the steering vector based on the phase difference of the depth of each element of the large-aperture vertical array relative to the reference element. Based on the steering vector, process the signal spectra of different elements using the spatial power spectrum estimation method to obtain spatial power spectrum estimation results at different arrival angles to achieve detection of the target sound source.

[0050] Specifically, the deployment depth of the large-aperture vertical array is 400-6000m, and the sea depth D of the deep sea ranges from 1000-6000m.

[0051] Specifically, the depths of the elements of the large aperture vertical array are d1, ..., d m ,...,d M ; Where d1 is the depth of the first array element, d m is the depth of the mth array element, d M is the depth of the Mth array element; the total number of array elements of the large aperture vertical array is M, and the sampling rate of the large aperture vertical array is f s , the sampling rate f s The range is 100Hz~40kHz.

[0052] Specifically, in step 2, the time domain signal received by the mth array element is subjected to fast Fourier transform to obtain the signal at frequency f. l The signal spectrum at x m (f l ); where l = 1, 2, ..., L, where L is the number of frequency points used. f1 is the preset lower bound of the frequency range of the spatial power spectrum estimation during target detection, and f L The preset upper bound of the frequency range of the spatial power spectrum estimation for target detection.

[0053] Specifically, the preset lower bound f1 of the target detection spatial power spectrum estimation frequency range is in the range of 0.1 Hz to 3.5 kHz, and the preset upper bound f L The range is 5Hz~4kHz.

[0054] Specifically, the spatial power spectrum estimation method includes: a conventional beamforming spatial power spectrum estimation method.

[0055] Specifically, the step 3 includes:

[0056] Calculate at frequency f l And the angle θ k The beam output sound field B(θ k ):

[0057]

[0058] Where, the arrival angle θ k From -90° to 90°, the value is taken every 0.01° to 1°; A(θ k ,f l ) is the steering vector obtained by calculating the phase difference between the depth of each element of the large aperture vertical array and the reference element during beamforming, wherein the reference element is any element in the large aperture vertical array; X(f l ) is the target sound source radiation signal received by the large aperture vertical array at the frequency point f l The spectrum vector at the location; the superscript H represents the conjugate transpose operator; f1 is the preset lower bound of the frequency range of the spatial power spectrum estimation during target detection, f L is the preset upper bound of the frequency range of the spatial power spectrum estimation during target detection;

[0059]

[0060] Where, for an arrival angle θ greater than zero degrees k , propagation path length r m (θ k )for:

[0061]

[0062] Among them, d ref is the depth of the reference element, d m is the depth of the mth array element;

[0063] For an arrival angle θ equal to zero degrees k , propagation path length r m (θ k )for:

[0064] rm (θ k )=d m

[0065] For an arrival angle θ less than zero degrees k , propagation path length r m (θ k )for:

[0066]

[0067] Where D is the ocean depth; c is the seawater sound speed at the center of the receiving array.

[0068] Specifically, the reference array element is an array element at the center of a large aperture vertical array.

[0069] Specifically, the target sound source radiation signal received by the large aperture vertical array is at the frequency point f l The spectrum vector X(f l )for:

[0070] X(f l )=[x1(f l ),x2(f l ),...,x m (f l ),...,x M (f l )] T

[0071] Among them, x1(f l ) is the first array element at frequency f l The signal spectrum at x2(f l ) is the second array element at frequency f l The signal spectrum at x m (f l ) is the mth array element at frequency f l The signal spectrum at x M (f l ) is the Mth array element at frequency f l The signal spectrum at ; the total number of array elements of the large aperture vertical array is M; the superscript T represents the transpose operator.

[0072] The following will illustrate this method using a simulation experiment of underwater sound source radiation signals received by a deep-sea vertical array deployed near the seabed as an example. The sea depth in the simulation experiment is 3000m, and the seawater sound velocity profile used in the simulation is shown in Figures 2(a) and 2(b). The receiving array is a 200-element synchronous equidistant vertical linear array deployed near the seabed, with an array aperture of 1000m, an array element spacing of 5m, an array center depth of approximately 2440m, and an array deployment depth of 1000m. Figure 1The sound source depth is set to 200m. The sound source first approaches and then moves away from the receiving array. The receiving and transmitting distance first decreases from 15km to 2.6km and then increases to 11.2km. Figure 2(a) shows the motion trajectory of the sound source target relative to the vertical array, and Figure 2(b) shows the receiving and transmitting distance information of the sound source target relative to the vertical array. The target sound source is detected through fast Fourier transform, steering vector calculation, spatial power spectrum estimation and other processing. Figure 5 As shown, the process is divided into the following steps:

[0073] Step 1: 200 yuan synchronous vertical linear array is deployed near the seabed to collect the time domain signal p radiated by the target sound source m (t), the vertical array element depth increases from 1940m to 2940m.

[0074] Step 2: Perform fast Fourier transform on the time domain signal collected by the vertical array element array to obtain the mth array element at frequency f l The spectrum at x m (f l ), where l = 1, 2, ..., L, L is the number of frequency points used, f1 and f L They are the lower and upper bounds of the frequency range selected for spatial power spectrum estimation during target detection, respectively. The range of f1 is 0.1Hz~3.5kHz, and f L The range of f1 is 5Hz~4kHz. In this embodiment, f1 and f L The values ​​are 50Hz and 100Hz respectively. The target sound source radiation signal received by the vertical array is at the frequency point f l The spectrum vector X(f l )for:

[0075] X(f l )=[x1(f l ),x2(f l ),...,x M (f l )] T

[0076] Where, the superscript T represents the transposition operator;

[0077] Step 3: Use conventional beamforming and other spatial power spectrum estimation methods to calculate the spatial power spectrum of the vertical array at different angles. Taking the conventional beamforming method as an example, the following formula is used to calculate the spatial power spectrum at the frequency point f l , angle θ k The beam output sound field B(θ k ):

[0078]

[0079] Where, the arrival angle θk The angle range is from -90° to 90°, and the angle interval is set to 0.01° to 1°. In this embodiment, the angle interval is set to 0.2°; A(θ k ,f l ) is the steering vector A(θ used in beamforming k ,f l ):

[0080]

[0081] For an arrival angle θ equal to zero degrees k , propagation path length r m (θ k )=d m ;

[0082] For θ greater than zero degrees k , propagation path length Among them, d ref is the depth of the reference array element. In this embodiment, the reference array element is selected as the array element at the vertical center of the array;

[0083] For θ less than zero degrees k , propagation path length Where D is the sea depth, which is 3000m. c is the seawater sound velocity at the center of the receiving array, and the superscript H represents the conjugate transpose operator.

[0084] Example 2

[0085] This embodiment provides a target detection system based on a deep-sea large-aperture vertical array, including:

[0086] A large-aperture vertical array, deployed on the bottom of the deep sea, is used to receive time-domain signals radiated by target sound sources;

[0087] A fast Fourier transform module, used to perform fast Fourier transform on the time domain signal received by each array element to obtain the corresponding signal spectrum; and

[0088] The estimation module is used to calculate the steering vector based on the phase difference of the depth of each element of the large-aperture vertical array relative to the reference element; based on the steering vector, it is used to process the signal spectra of different elements using the spatial power spectrum estimation method to obtain spatial power spectrum estimation results at different arrival angles to achieve detection of the target sound source.

[0089] Figure 3 shows the spatial power spectrum estimation results for a target sound source during its motion when the source level is high and under high signal-to-noise ratio conditions. Figure 3(a) shows the results based on the plane wave assumption, while Figure 3(b) shows the results of our proposed method. As can be seen, the peak value in Figure 3(a) is 105.7 dB. Due to the differences in the arrival angles of the target sound source relative to different array elements, the target sound source energy is dispersed across a certain range of arrival angles in the spatial power spectrum estimation results based on the plane wave assumption in far-field conditions, which reduces the detection capability of the target sound source. Meanwhile, the direct wave and the sea surface reflection wave are both lost. However, the peak value of our proposed method, shown in Figure 3(b), is 109.9 dB, which better achieves in-phase superposition detection of the received signals from each element in the vertical array. Furthermore, our method better preserves the channel response from the target sound source to the reference array element, and the arrival angle variations corresponding to the multipath paths of the direct wave, sea surface reflection wave, seabed reflection wave, and seabed and sea surface reflection wave are more clearly shown in the spatial power spectrum estimation results. Figure 4 shows the results of the spatial power spectrum estimation during target sound source motion when the target sound source level is low. Figure 4(a) shows the result based on the plane wave assumption, while Figure 4(b) shows the result of our method. It can be seen that the traditional spatial power spectrum estimation method based on the plane wave assumption shown in Figure 4(a) does not clearly show the trajectory of the target sound source's arrival angle changes during the entire target motion period. However, in the results of our method shown in Figure 4(b), the trajectory of the target sound source's arrival angle changes can be clearly observed during the 20-45 minute period, enabling detection of the target sound source.

[0090] The present invention selects a certain array element of the vertical array as the phase reference point, and innovatively proposes a target detection method and system based on a deep-sea large-aperture vertical array. The present invention ignores the difference in sound speed at different depths of seawater, and based on the assumption that the sound speed of seawater from the sea surface to the seabed in the deep sea is constant, the geometric relationship is used to calculate the phase difference of other array elements of the vertical array relative to the reference array element, and the corresponding steering vector is constructed based on the phase difference, thereby solving the problem of different arrival angles of the sound source at different array elements and improving the target detection performance. In addition, since a certain array element is selected as the reference array element to construct the steering vector, the target detection method and system proposed by the present invention retain the channel response from the target sound source to the reference array element. Therefore, the target detection method and system proposed by the present invention can be further used in subsequent related work such as target position and ocean environment parameter inversion.

[0091] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and are intended to be encompassed by the claims of the present invention.

Claims

1. A target detection method based on a deep-sea large-aperture vertical array, comprising: Step 1: Receive the time domain signal radiated by the target sound source through a large-aperture vertical array deployed on the bottom of the deep sea; Step 2: Perform fast Fourier transform on the time domain signal received by each array element to obtain the corresponding signal spectrum; Step 3: Calculate the steering vector based on the phase difference of the depth of each element of the large-aperture vertical array relative to the reference element. Based on the steering vector, process the signal spectra of different elements using the spatial power spectrum estimation method to obtain spatial power spectrum estimation results at different arrival angles to achieve detection of the target sound source.

2. The target detection method based on deep-sea large aperture vertical array according to claim 1, characterized in that: The deployment depth of the large-aperture vertical array is 400-6000m, and the sea depth D of the deep sea ranges from 1000-6000m.

3. The target detection method based on deep-sea large aperture vertical array according to claim 1, characterized in that: The depths of the elements of the large aperture vertical array are d1,...,d m ,...,d M ; Among them, d1 is the depth of the first array element, d m is the depth of the mth array element, d M is the depth of the Mth array element; the total number of array elements of the large aperture vertical array is M, and the sampling rate of the large aperture vertical array is f s , the sampling rate f s The range is 100Hz~40kHz.

4. The target detection method based on deep-sea large aperture vertical array according to claim 1, characterized in that: In step 2, the time domain signal received by the mth array element is subjected to fast Fourier transform to obtain the signal at frequency f l The signal spectrum at x m (f l ); where l = 1, 2, ..., L, L is the number of frequency points used, f1 is the preset lower bound of the frequency range of the spatial power spectrum estimation during target detection, and f L The preset upper bound of the frequency range of the spatial power spectrum estimation for target detection.

5. The target detection method based on deep-sea large aperture vertical array according to claim 4, characterized in that: The preset lower bound f1 of the target detection spatial power spectrum estimation frequency range is in the range of 0.1 Hz to 3.5 kHz, and the preset upper bound f L The range is 5Hz~4kHz.

6. The target detection method based on deep-sea large aperture vertical array according to claim 1, characterized in that: The spatial power spectrum estimation method includes: a conventional beamforming spatial power spectrum estimation method.

7. The target detection method based on deep-sea large aperture vertical array according to claim 6, characterized in that: The step 3 specifically includes: Calculate at frequency f l And the angle θ k The beam output sound field B(θ k ): Where, the arrival angle θ k From -90° to 90°, the value is taken every 0.01° to 1°; A(θ k ,f l ) is the steering vector obtained by calculating the phase difference between the depth of each element of the large aperture vertical array and the reference element during beamforming, wherein the reference element is any element in the large aperture vertical array; X(f l ) is the target sound source radiation signal received by the large aperture vertical array at the frequency point f l The spectrum vector at the location; the superscript H represents the conjugate transpose operator; f1 is the preset lower bound of the frequency range of the spatial power spectrum estimation during target detection, f L is the preset upper bound of the frequency range of the spatial power spectrum estimation during target detection; Where, for an arrival angle θ greater than zero degrees k , propagation path length r m (θ k )for: Among them, d ref is the depth of the reference element, d m is the depth of the mth array element; For an arrival angle θ equal to zero degrees k , propagation path length r m (θ k )for: r m (i k )=d m For an arrival angle θ less than zero degrees k , propagation path length r m (θ k )for: Where D is the ocean depth; c is the seawater sound speed at the center of the receiving array.

8. The target detection method based on deep-sea large aperture vertical array according to claim 7, characterized in that: The reference array element is an array element at the center of a large aperture vertical array.

9. The target detection method based on deep-sea large aperture vertical array according to claim 7, characterized in that: The target sound source radiation signal received by the large aperture vertical array is at the frequency point f l The spectrum vector X(f l )for: X(f l )=[x1(f l ),x2(f l ),...,x m (f l ),...,x M (f l )] T Among them, x1(f l ) is the first array element at frequency f l The signal spectrum at x2(f l ) is the second array element at frequency f l The signal spectrum at x m (f l ) is the mth array element at frequency f l The signal spectrum at x M (f l ) is the Mth array element at frequency f l The signal spectrum at ; the total number of array elements of the large aperture vertical array is M; the superscript T represents the transpose operator.

10. A target detection system based on a deep-sea large-aperture vertical array, comprising: A large-aperture vertical array, deployed on the bottom of the deep sea, is used to receive time-domain signals radiated by target sound sources; A fast Fourier transform module is used to perform fast Fourier transform on the time domain signal received by each array element to obtain the corresponding signal spectrum; and The estimation module is used to calculate the steering vector based on the phase difference of the depth of each element of the large-aperture vertical array relative to the reference element; based on the steering vector, it is used to process the signal spectra of different elements using the spatial power spectrum estimation method to obtain spatial power spectrum estimation results at different arrival angles to achieve detection of the target sound source.

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