A deep sea horizontal array sound source passive positioning method and system based on high-precision azimuth angle estimation

Abstract

The application relates to the field of underwater acoustic engineering, ocean engineering and sonar technology, in particular to a deep-sea horizontal array sound source passive positioning method and system based on high-precision azimuth angle estimation. The method samples sound source signals through a horizontal array and estimates the earliest arrival time, constructs a stripe slope cost function after Fourier transform and phase compensation, and obtains a reference value through blind search, combines the reference value to construct a frequency shift data beam forming to obtain a high-precision azimuth angle, simultaneously obtains a solid angle through conventional beam forming, and decouples to obtain a pitch angle; theoretical time delays of different assumed depths are calculated, a measured time delay spectrum is obtained from wideband beam output, and after matching, the actual depth of the sound source is determined according to the minimum value of the cost function. The application reduces the calculation amount, realizes decoupling of the horizontal array azimuth angle and the pitch angle, solves the problems of no pitch angle estimation capability of the horizontal array and depth ambiguity of the traditional method, and improves the efficiency and precision of deep-sea sound source passive positioning.

Description

Technical Field

[0001] This application relates to the fields of underwater acoustic engineering, marine engineering, and sonar technology, and in particular to a passive localization method and system for deep-sea horizontal array acoustic sources based on high-precision azimuth estimation. Background Technology

[0002] Deep-sea passive sound source localization has always been a hot research topic in the field of underwater acoustics. Traditional matched-field methods estimate the distance and depth of the sound source by matching the measured sound field with a copied sound field. However, the processes of copying the sound field and matching the measured field with the copied field are computationally intensive and time-consuming, and the accuracy of the matched-field method is easily affected by the mismatch of marine environmental parameters, resulting in poor tolerance.

[0003] Deep-sea sound fields exhibit distinct interference structures, and the fluctuation period of the interference fringe intensity is directly related to the sound source depth. Compared to directly matching the received sound pressure, matching the multipath interference features extracted from the received sound field has a clearer physical meaning. Existing methods for estimating sound source depth or distance using multipath interference features generally require the use of the arrival elevation angle information of the multipath signals to solve the coupling problem between sound source distance and depth estimation. This necessitates that the receiving array has elevation angle estimation capabilities. Therefore, most publicly available technologies employ vector hydrophones or vertical hydrophone arrays as receiving sensing devices. For horizontal arrays, a commonly used array configuration, most existing methods are unsuitable or limited to distance estimation scenarios for near-surface sound sources with known depths due to their lack of arrival signal elevation angle estimation capabilities. Furthermore, they suffer from depth ambiguity issues, making it impossible to estimate both sound source depth and distance. The patent with patent number ZL202411119047.X, entitled "A Passive Positioning Method and Device for Deep-Sea Targets Using a Horizontal Array", proposes a passive positioning method for targets that is adapted to deep-sea horizontal arrays and achieves target passive positioning by matching the arrival time delay of four paths. However, this method requires the received signal to have four arrival paths with equivalent energy, which is suitable for deep-sea shadow areas. Summary of the Invention

[0004] The purpose of this application is to overcome the problems of existing horizontal array positioning methods, which cannot obtain elevation angle information due to the lack of vertical aperture, and the depth ambiguity of existing interferometric feature positioning methods, thereby providing a passive positioning method and system for deep-sea horizontal array sound sources based on high-precision azimuth angle estimation.

[0005] To solve the above-mentioned technical problems, the technical solution of this application provides a passive localization method for deep-sea horizontal array acoustic sources based on high-precision azimuth estimation, comprising: Step 1: Perform time-domain sampling of the sound source signal in the deep sea using a horizontal array, select a reference array element, and estimate the earliest arrival time of the signal based on the time-domain waveform of the reference array element; Step 2: Perform Fourier transform on the time-domain sound source signals received by each element of the horizontal array to obtain array frequency domain data, and use the earliest arrival time of the signal to perform phase compensation on the frequency domain data; Step 3: Construct a fringe slope cost function that varies with frequency, perform a blind search on the fringe slope, and extract the fringe slope value that maximizes the beam output as the fringe slope reference value. Step 4: Construct broadband sound pressure frequency shift data based on the fringe slope reference value, and use the broadband sound pressure frequency shift data to perform beamforming to obtain a high-precision sound source azimuth angle estimate; and perform conventional beamforming on the phase-compensated frequency domain data to obtain a solid angle estimate that couples the azimuth and elevation angles. Step 5: Using the high-precision azimuth and solid angle estimates of the sound source, obtain the pitch angle estimate of the sound source; Step 6: Calculate the theoretical time delay corresponding to different assumed sound source depths in the deep sea using the estimated sound source pitch angle; Step 7: Use the broadband beam output results at the high-precision azimuth angle estimation value of the sound source to obtain the measured arrival time delay spectrum of the sound source; Step 8: Extract the peak value corresponding to the measured arrival delay spectrum of the sound source, match the peak value corresponding to the theoretical delay corresponding to different assumed sound source depths, and estimate the actual depth of the sound source based on the matching results.

[0006] As an improvement to the above technical solution, the specific operation of time-domain sampling of the sound source signal in step 1 includes: The received sound source signal is recorded by a horizontal array. The time-domain waveform obtained by each array element is ,in, The ordinal number of the array element. , The total number of elements in the horizontal array is , and the array length of the horizontal array is . L , No. The position of each element is ,satisfy , The signal sampling time is [value], and the total signal duration is [value]. ,satisfy .

[0007] As an improvement to the above technical solution, step 2 specifically includes: Select the Each array element serves as a reference array element; the time-domain signal recorded for the reference array elements. Select the time corresponding to the earliest arrival of the sample. As the earliest arrival time of the signal; for the time-domain waveforms of each array element. Perform a Fourier transform to obtain the frequency domain data of the array. ,in, For the signal frequency, satisfying Hz; based on the earliest arrival time of the signal Using the formula For frequency domain data Phase compensation is performed, where j is the imaginary unit.

[0008] As an improvement to the above technical solution, step 3 specifically includes: By selecting different fringe slope values, a cost function for the fringe slope varying with frequency is constructed: ; in, It is the slope of the stripes being searched. Hz / m, It's from the perspective of searching. , For signal frequency, It is the number of discrete frequency points, and , The total number of elements in the horizontal array. [This refers to the frequency band range under study.] It is the minimum value of the frequency band under study. It is the maximum value of the frequency band under study, satisfying Hz, The first fringe slope represents the slope along the fringe. Frequency domain data of each array element To process the center frequency of the frequency band, For the first The position of each array element To account for the frequency variation of broadband signals at the signal frequency The slope value of the stripes at that point, For broadband signal stripes at frequency Frequency offset at that location It is the reference speed of sound, the reference speed of sound When the waveguide sound velocity profile is known, it is the average value of the waveguide sound velocity profile; when the waveguide sound velocity profile is unknown, it is a preset value. A blind search is performed on the fringe slope to extract the fringe slope value that maximizes the beam output, which is then used as a reference value for the fringe slope. .

[0009] As an improvement to the above technical solution, step 4 specifically includes: Based on the stripe slope reference value Calculate the frequency-dependent broadband slope value and construct broadband sound pressure frequency shift data with optimized amplitude and phase consistency; Beamforming is performed using the broadband sound pressure frequency shift data to obtain the corresponding first output result. The search results the first beam output. The maximum azimuth angle is used as the high-precision azimuth angle estimate of the sound source. ,satisfy: ; For high-precision sound source azimuth angle estimation value The beam output results; By setting the fringe slope to 0, conventional beamforming is performed on the phase-compensated frequency domain data to obtain the corresponding second output result. The search results in the second beam output. The largest azimuth angle is used as the solid angle estimate. ,satisfy , solid angle estimate The beam output results.

[0010] As an improvement to the above technical solution, step 5 specifically includes: High-precision sound source azimuth angle estimation value and solid angle estimation value Substitute into the coupling formula The estimated value of the pitch angle α of the decoupled sound source was calculated.

[0011] As an improvement to the above technical solution, step 6 specifically includes: Substituting the estimated pitch angle α of the sound source into the theoretical time delay calculation formula, the depth of the sound source under different assumptions is calculated. Corresponding theoretical delay : ; in, For receiving depth The corresponding speed of sound, For receiving depth, Let z be the speed of sound at depth z. For depth, satisfy .

[0012] As an improvement to the above technical solution, step 7 specifically includes: For high-precision sound source azimuth angle The beam output results at the specified location are subjected to frequency domain mean-reduction processing, and the mean-reduction beam output spectrum is obtained. satisfy: ; in, For frequency point index, Frequency point index Frequency at that location To handle the total number of frequency points within the frequency band, For high-precision sound source azimuth angle The beam output sound field intensity; Beam output spectrum after mean removal Perform an inverse Fourier transform to obtain the measured arrival time delay spectrum of the sound source. : ; in For arrival delay.

[0013] As an improvement to the above technical solution, step 8 specifically includes: Extracting the measured arrival time delay spectrum of the sound source The time delay corresponding to the mid-peak value is used as the measured dominant path time delay of the sound source. The measured dominant path delay of the sound source Theoretical time delay corresponding to different assumed sound source depths Perform matching and construct the cost function. , where the cost function satisfy: , The arrival delay spectrum after matching is represented; the assumed sound source depth that minimizes the cost function is selected as the estimated actual sound source depth. : ; in, Assuming the depth of the sound source, Assuming the depth of the sound source The corresponding cost function, Represents constraint symbols.

[0014] To achieve another objective of the present invention, the present invention also provides a passive positioning system for a deep-sea horizontal array acoustic source based on high-precision azimuth estimation, comprising: The signal sampling module is used to perform time-domain sampling of sound source signals in the deep sea through a horizontal array, select reference array elements, and estimate the earliest arrival time of the signal based on the time-domain waveform of the reference array elements. The frequency domain processing and phase compensation module is used to perform Fourier transform on the time domain sound source signals received by each element of the horizontal array to obtain array frequency domain data, and to perform phase compensation on the frequency domain data using the earliest arrival time of the signal. The fringe slope search module is used to construct a fringe slope cost function that varies with frequency, perform a blind search on the fringe slope, and extract the fringe slope value that maximizes the beam output as the fringe slope reference value. An angle estimation module is used to construct broadband sound pressure frequency shift data based on the fringe slope reference value, perform beamforming using the broadband sound pressure frequency shift data to obtain a high-precision sound source azimuth angle estimate; and perform conventional beamforming on the phase-compensated frequency domain data to obtain a solid angle estimate coupled with the azimuth angle and elevation angle. The pitch angle decoupling module is used to obtain the pitch angle estimate of the sound source by utilizing the high-precision azimuth angle estimate and solid angle estimate of the sound source; The theoretical time delay calculation module is used to calculate the theoretical time delay corresponding to different assumed sound source depths in the deep sea using the estimated sound source pitch angle; The measured time delay spectrum acquisition module is used to obtain the measured arrival time delay spectrum of the sound source by utilizing the broadband beam output results at the high-precision azimuth angle estimation value of the sound source; and The sound source depth estimation module is used to extract the peak value corresponding to the measured arrival time delay spectrum of the sound source, match the peak value corresponding to the theoretical time delay corresponding to different assumed sound source depths, and estimate the actual depth of the sound source based on the matching results.

[0015] The advantages of this application are that, compared with traditional matched-field methods, since it only calculates and matches the arrival delay template value that contributes the most, without calculating the copied sound field or matching the measured field with the copied field, it significantly reduces the computational load and improves the efficiency of real-time localization of passive sound sources. Furthermore, this method uses a horizontal array to decouple the solid angle and azimuth angle, obtaining azimuth and elevation angle information separately. This overcomes the limitation of the horizontal array not being able to obtain the elevation angle and avoids the depth ambiguity problem inherent in existing localization methods based on interferometric features. Attached Figure Description

[0016] Figure 1 This is a simulation of the sound velocity profile in Example 1; Figure 2 This is a time-domain diagram of the signal received by the horizontal array in Example 1; Figure 3 This is the array element position-frequency amplitude spectrum of the received signal in Example 1; Figure 4 This is the azimuth-fringe slope blind search map from Example 1; Figure 5 These are beam output scan diagrams of conventional beamforming and fringe beamforming in Example 1; Figure 6 This is the broadband beam output spectrum along the azimuth angle of the sound source in Example 1. Figure 7This is the actual arrival time delay spectrum of the sound source in Example 1; Figure 8 It is the cost function for matching the actual arrival delay with the theoretical delay in Example 1; Figure 9 This is a flowchart of the passive localization method for deep-sea horizontal array acoustic sources based on high-precision azimuth estimation provided in Example 1. Detailed Implementation

[0017] The technical solutions provided in this application are further illustrated below with reference to the embodiments.

[0018] Example 1 This embodiment proposes a passive localization method for deep-sea horizontal array acoustic sources based on high-precision azimuth angle. For example... Figure 9 As shown, firstly, the received signal is sampled in the time domain using a horizontal array, and the signal arrival time is estimated based on the time-domain waveform of the reference array element. Secondly, Fourier transform is performed on the received signal of each array element to obtain frequency domain data, and the estimated signal arrival time is used to perform phase compensation on the frequency domain data. Next, a cost function of the fringe slope that varies with frequency is constructed, and a reference value of the fringe slope that maximizes the beam output is extracted by blindly searching the fringe slope. Subsequently, a broadband slope value related to the frequency is calculated based on the fringe slope reference value, thereby constructing broadband sound pressure frequency shift data with better amplitude and phase consistency. Finally, beamforming is performed using the obtained sound pressure frequency shift data to achieve high-precision sound source azimuth angle estimation. Simultaneously, conventional beamforming is performed using sound pressure frequency domain data to obtain the solid angle coupled with the elevation angle. Then, using the coupling formula between the solid angle and elevation angle, the elevation angle is estimated by decoupling the high-precision sound source azimuth and solid angle. Next, the elevation angle is substituted into the theoretical time delay calculation formula to calculate the theoretical time delay corresponding to different assumed depths. Subsequently, spectral analysis is performed along the frequency axis on the broadband beam sound field intensity at the sound source azimuth using the fringe slope reference value to obtain the measured arrival time delay spectrum of the sound source. Finally, a cost function is constructed to match the measured arrival time delay spectrum of the sound source with the theoretically calculated time delays corresponding to different assumed depths, and the depth of the sound source is estimated based on the matching results. The specific steps are as follows: Step 1: A horizontal array records the received signal, the first... The time-domain waveform obtained by each array element is ,in The total number of array elements; the array length is L , No. The position of each element is ,satisfy The unit is meters. The signal sampling time is [value], and the total signal duration is [value]. ,satisfy The unit is seconds.

[0019] Step 2: Select the first Each array element serves as a reference element, recording the time-domain signal for that element. Select the time corresponding to the earliest arriving sample The frequency domain data of the array is obtained by performing Fourier transform on the time-domain waveforms obtained from each array element. ,satisfy For the signal frequency, satisfying Hz. For frequency domain data Perform phase compensation to satisfy Step 3: Perform a blind search for the maximum beam output value under different fringe slope values, and construct the cost function through beamforming as follows. in [ ] is the frequency band range under study, which meets the requirements. Hz, It is the number of discrete frequency points, satisfying . This is the reference speed of sound, measured in m / s. The average value of the waveguide sound velocity profile is usually chosen. When this value is unknown, 1500 m / s can be selected. From the perspective of searching, it satisfies . This refers to the slope of the stripes being searched; the search range is typically set to satisfy... Hz / m, this range can also be adjusted as needed. To process the center frequency of the frequency band, To account for the frequency variation of broadband signals at frequency The slope value of the stripes at that point, For broadband signal stripes at frequency Frequency offset at that location The first fringe slope represents the slope along the fringe. Frequency domain data of each array element.

[0020] Step 4: Search The beam output estimation result when the maximum value is taken satisfies ,in, , These are the lower and upper limits of the slope search range, respectively. For selection The source azimuth obtained by beamforming at the fringe slope at the reference frequency, i.e., the estimated source azimuth, satisfies... .at the same time, The azimuth obtained by beamforming at a reference frequency with a fringe slope of 0 is the solid angle estimate of the conventional beamforming output. This satisfies... .

[0021] Step 5: Estimate the location of the sound source. Estimated solid angle of sound source Substitute into the formula ,in This is an estimate of the pitch angle of the decoupled sound source.

[0022] Step 6: Estimate the pitch angle of the sound source. Substituting into the time delay formula, we calculate the theoretical time delay corresponding to different assumed depths. The theoretical time delays at different depths satisfy the following: ,in Assuming the depth of the sound source, For receiving depth The corresponding speed of sound, For receiving depth, Let z be the speed of sound at depth z. For depth, satisfy .

[0023] Step 7: Output the beam from Step 4 In the frequency domain, mean-reduction processing is performed, and the mean-reduced beam output spectrum is obtained using the following formula: ,in This is the estimated azimuth angle. For frequency point index, Frequency point index Frequency at that location To handle the number of frequency points contained within a frequency band, To estimate the beam output sound field intensity at the azimuth angle, the mean-free beam output sound field intensity spectrum is processed. Perform an inverse Fourier transform to obtain the measured arrival time delay spectrum: ,in, It is an imaginary number. For arrival delay, For frequency, [ ] represents the frequency band range under study.

[0024] Step 8: Obtain the arrival time delay spectrum The time delay corresponding to the mid-peak value is the measured time delay of the dominant path of the sound source. The measured arrival delay Compared with the theoretical delay calculated in step 6 Perform matching to obtain the cost function for sound source depth estimation. ,satisfy The depth corresponding to the minimum value of the cost function is taken as the estimated depth of the sound source, i.e. ,in, To estimate the depth of the sound source, For constraint symbols, Assuming the depth of the sound source, Assuming the depth of the sound source The corresponding cost function.

[0025] The present invention will now be further described in conjunction with the embodiments and accompanying drawings: The passive localization method for deep-sea horizontal array acoustic sources based on high-precision azimuth angle provided in this embodiment firstly samples the received signal in the time domain using the horizontal array and estimates the signal arrival time based on the time domain waveform of the reference array element. Secondly, Fourier transform is performed on the received signal of each array element to obtain frequency domain data, and phase compensation is performed on the frequency domain data using the estimated signal arrival time. Next, a cost function of the fringe slope that varies with frequency is constructed, and a reference value of the fringe slope that maximizes the beam output is extracted by blindly searching the fringe slope. Subsequently, a broadband slope value related to the frequency is calculated based on the fringe slope reference value, thereby constructing broadband sound pressure frequency shift data with better amplitude and phase consistency. Finally, beamforming is performed using the obtained sound pressure frequency shift data to achieve high-precision azimuth angle estimation of the acoustic source. Simultaneously, conventional beamforming is performed using sound pressure frequency domain data to obtain the solid angle coupled with the elevation angle. Subsequently, the elevation angle is estimated by decoupling the sound source azimuth and solid angle using the coupling formula of the solid angle and elevation angle. Then, the elevation angle is substituted into the theoretical time delay calculation formula to calculate the theoretical time delay corresponding to different assumed depths. Subsequently, the broadband beam sound field intensity at the sound source azimuth using the fringe slope reference value is spectrally analyzed along the frequency axis to obtain the measured arrival time delay spectrum of the sound source. Then, a cost function is constructed to match the measured arrival time delay spectrum of the sound source with the theoretically calculated time delay corresponding to different assumed depths, and the depth of the sound source is estimated based on the matching result.

[0026] This embodiment uses simulation data of direct-range sound source radiation signals received by a horizontal array arranged on the deep seabed as an example. The sound velocity profile is as follows: Figure 1 The simulated seawater depth is 3000m, and the seawater density is 1.0g / L. Seawater absorbs sound silently. The speed of sound on the seabed is 1555 m / s, and the density is 1.8 g / L. Absorption at seabed: 0.3 dB / , Indicates the wavelength of the sound wave; the spectrum of the sound source. =1, sound source depth is 200m; uniform horizontal receiving array aperture is 500m, array element spacing The deployment depth is 2990m; the horizontal distance between the sound source and the center point of the receiving array is 10.5km. Background noise is not considered in the simulation. The specific steps are as follows: Step 1: Receive signals from the horizontal array pair Record it, among which ; array length is L= 500m , No. i The position of each element is The unit is meters (symbol) m ). The signal sampling time is [value], and the total signal duration is [value]. ,satisfy The unit is seconds (symbol) s ).

[0027] Step 2: Select the 101st array element as the reference signal and analyze the time-domain signal recorded by this element. The time-domain signal received by the reference array element in this embodiment is as follows: Figure 2 As shown. Estimated earliest arrival time of the signal. =7.04s. Fourier transforms were performed on the time-domain waveforms obtained from each array element to obtain the array's frequency-domain data. ,satisfy For the signal frequency, satisfying Hz. For frequency domain data Perform phase compensation to satisfy The obtained sound pressure amplitude spectrum of array element position-frequency is as follows: Figure 3 As shown.

[0028] Step 3: Perform a blind search for the maximum beam output value under different fringe slope values, and construct the cost function through beamforming as follows.

[0029] The frequency band under study is [200, 300] Hz, with 10001 discrete frequency points, satisfying the following conditions: Reference speed of sound The value was chosen as 1521 m / s. From the perspective of searching, it satisfies . It is the slope of the stripes being searched, and the search range is set to satisfy... Hz / m. Center frequency of the processed frequency band. =250Hz, To account for the frequency variation of broadband signals at frequency The slope value of the stripes at that point, For broadband signal stripes at frequency The frequency offset at that point. This is obtained as follows: Figure 4 The azimuth-fringe slope search diagram is shown.

[0030] Step 4: Search The beam output estimation result when the maximum value is taken satisfies: .

[0031] like Figure 4As shown, the cost function is The value is maximized at 0.0296 Hz / m. This represents the fringe slope at the reference frequency of 250 Hz. Figure 5 The image shows the beam output with fringe slopes of 0.0296 Hz / m and 0 Hz / m, and the estimated beam output azimuth and solid angle values ​​are as follows: , ,satisfy , .

[0032] Step 5: Estimate the location of the sound source. Estimated solid angle of sound source Substitute into the formula The estimated value of the pitch angle of the decoupled sound source was obtained by calculation. =17.08 .

[0033] Step 6: Estimate the pitch angle of the sound source. Substituting into the time delay formula, we calculate the theoretical time delay corresponding to different assumed depths. The theoretical time delays at different depths satisfy the following: ,in For the assumed sound source depth, satisfying m.

[0034] Step 7: Output the beam from Step 4 In the frequency domain, mean-reduction processing is performed, and the mean-reduced beam output spectrum is obtained using the following formula: Among them, the estimated azimuth angle , For frequency point index, Frequency point index The frequency at that location is within a processing frequency range of [200, 300] Hz, and the number of frequency points included is 10001. To estimate the beam output sound field intensity at the azimuth angle; the beam output sound field intensity spectrum after mean removal processing. The results are as follows Figure 6 As shown. The beam output sound field intensity spectrum after mean-free processing. Perform an inverse Fourier transform to obtain the measured arrival time delay spectrum: ,in, For arrival delay, Frequency. Measured arrival time delay spectrum. like Figure 7 As shown.

[0035] Step 8: Obtain the arrival time delay spectrum The time delay corresponding to the mid-peak value is the measured time delay of the dominant path of the sound source. The measured arrival delay Compared with the theoretical delay calculated in step 7 Perform matching to obtain the cost function for sound source depth estimation. ,satisfy The depth corresponding to the maximum value of the cost function is taken as the estimated depth of the sound source, i.e. The calculated cost function is as follows: Figure 8 As shown, the estimated sound source depth is 179.5m, which is close to the actual sound source depth, and the error is within the allowable range.

[0036] Example 2 The passive positioning system for deep-sea horizontal array acoustic sources based on high-precision azimuth estimation proposed in this embodiment includes: The signal sampling module is used to perform time-domain sampling of sound source signals in the deep sea through a horizontal array, select reference array elements, and estimate the earliest arrival time of the signal based on the time-domain waveform of the reference array elements. The frequency domain processing and phase compensation module is used to perform Fourier transform on the time domain sound source signals received by each element of the horizontal array to obtain array frequency domain data, and to perform phase compensation on the frequency domain data using the earliest arrival time of the signal. The fringe slope search module is used to construct a fringe slope cost function that varies with frequency, perform a blind search on the fringe slope, and extract the fringe slope value that maximizes the beam output as the fringe slope reference value. An angle estimation module is used to construct broadband sound pressure frequency shift data based on the fringe slope reference value, perform beamforming using the broadband sound pressure frequency shift data to obtain a high-precision sound source azimuth angle estimate; and perform conventional beamforming on the phase-compensated frequency domain data to obtain a solid angle estimate coupled with the azimuth angle and elevation angle. The pitch angle decoupling module is used to obtain the pitch angle estimate of the sound source by utilizing the high-precision azimuth angle estimate and solid angle estimate of the sound source; The theoretical time delay calculation module is used to calculate the theoretical time delay corresponding to different assumed sound source depths in the deep sea using the estimated sound source pitch angle; The measured time delay spectrum acquisition module is used to obtain the measured arrival time delay spectrum of the sound source by utilizing the broadband beam output results at the high-precision azimuth angle estimation value of the sound source; and The sound source depth estimation module is used to extract the peak value corresponding to the measured arrival time delay spectrum of the sound source, match the peak value corresponding to the theoretical time delay corresponding to different assumed sound source depths, and estimate the actual depth of the sound source based on the matching results.

[0037] The positioning method and system proposed in this application utilize the mathematical coupling relationship between the solid angle, elevation angle, and azimuth angle obtained by conventional beamforming. It obtains a higher accuracy azimuth angle through fringe-based beamforming and decouples the azimuth angle and elevation angle from the solid angle obtained by conventional beamforming through a coupling formula. This solves the limitation that the horizontal array cannot obtain elevation angle information due to the lack of a vertical aperture, and avoids the depth ambiguity problem existing in the positioning method using interferometric features.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand 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 all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A passive localization method for deep-sea horizontal array acoustic sources based on high-precision azimuth estimation, comprising: Step 1: Perform time-domain sampling of the sound source signal in the deep sea using a horizontal array, select a reference array element, and estimate the earliest arrival time of the signal based on the time-domain waveform of the reference array element; Step 2: Perform Fourier transform on the time-domain sound source signals received by each element of the horizontal array to obtain array frequency domain data, and use the earliest arrival time of the signal to perform phase compensation on the frequency domain data; Step 3: Construct a fringe slope cost function that varies with frequency, perform a blind search on the fringe slope, and extract the fringe slope value that maximizes the beam output as the fringe slope reference value. Step 4: Construct broadband sound pressure frequency shift data based on the fringe slope reference value, and use the broadband sound pressure frequency shift data to perform beamforming to obtain a high-precision sound source azimuth angle estimate; and perform conventional beamforming on the phase-compensated frequency domain data to obtain a solid angle estimate that couples the azimuth and elevation angles. Step 5: Using the high-precision azimuth and solid angle estimates of the sound source, obtain the pitch angle estimate of the sound source; Step 6: Calculate the theoretical time delay corresponding to different assumed sound source depths in the deep sea using the estimated sound source pitch angle; Step 7: Use the broadband beam output results at the high-precision azimuth angle estimation value of the sound source to obtain the measured arrival time delay spectrum of the sound source; Step 8: Extract the peak value corresponding to the measured arrival delay spectrum of the sound source, match the peak value corresponding to the theoretical delay corresponding to different assumed sound source depths, and estimate the actual depth of the sound source based on the matching results.

2. The passive localization method for deep-sea horizontal array acoustic sources based on high-precision azimuth estimation according to claim 1, characterized in that, The specific operations for time-domain sampling of the sound source signal in step 1 include: The received sound source signal is recorded by a horizontal array. The time-domain waveform obtained by each array element is ,in, The ordinal number of the array element. , The total number of elements in the horizontal array is , and the array length of the horizontal array is . L , No. The position of each element is ,satisfy , The signal sampling time is [value], and the total signal duration is [value]. ,satisfy .

3. The passive localization method for deep-sea horizontal array acoustic sources based on high-precision azimuth estimation according to claim 1, characterized in that, Step 2 specifically includes: Select the Each array element serves as a reference array element; the time-domain signal recorded for the reference array elements. Select the time corresponding to the earliest arrival of the sample. As the earliest arrival time of the signal; for the time-domain waveforms of each array element. Perform a Fourier transform to obtain the frequency domain data of the array. ,in, For the signal frequency, satisfying Hz; based on the earliest arrival time of the signal Using the formula For frequency domain data Phase compensation is performed, where j is the imaginary unit.

4. The passive localization method for deep-sea horizontal array acoustic sources based on high-precision azimuth estimation according to claim 3, characterized in that, Step 3 specifically includes: By selecting different fringe slope values, a cost function for the fringe slope varying with frequency is constructed: ； in, It is the slope of the stripes being searched. Hz / m, It's from the perspective of searching. , For signal frequency, It is the total number of frequency points within the processing frequency band, and , The total number of elements in the horizontal array. [This refers to the frequency band range under study.] It is the minimum value of the frequency band under study. It is the maximum value of the frequency band under study, satisfying Hz, The first fringe slope represents the slope along the fringe. Frequency domain data of each array element To process the center frequency of the frequency band, For the first The position of each array element To account for the frequency variation of broadband signals at the signal frequency The slope value of the stripes at that point, For broadband signal stripes at frequency Frequency offset at that location It is the reference speed of sound, the reference speed of sound When the waveguide sound velocity profile is known, it is the average value of the waveguide sound velocity profile; when the waveguide sound velocity profile is unknown, it is a preset value. A blind search is performed on the fringe slope to extract the fringe slope value that maximizes the beam output, which is then used as a reference value for the fringe slope. .

5. The passive localization method for deep-sea horizontal array acoustic sources based on high-precision azimuth estimation according to claim 4, characterized in that, Step 4 specifically includes: Based on the stripe slope reference value Calculate the frequency-dependent broadband slope value and construct broadband sound pressure frequency shift data with optimized amplitude and phase consistency; Beamforming is performed using the broadband sound pressure frequency shift data to obtain the corresponding first output result. The search results the first beam output. The maximum azimuth angle is used as the high-precision azimuth angle estimate of the sound source. ,satisfy: ; For high-precision sound source azimuth angle estimation value The beam output results; By setting the fringe slope to 0, conventional beamforming is performed on the phase-compensated frequency domain data to obtain the corresponding second output result. The search results in the second beam output. The largest azimuth angle is used as the solid angle estimate. ,satisfy , solid angle estimate The beam output results.

6. The passive localization method for deep-sea horizontal array acoustic sources based on high-precision azimuth estimation according to claim 5, characterized in that, Step 5 specifically includes: High-precision sound source azimuth angle estimation value and solid angle estimation value Substitute into the coupling formula The estimated pitch angle of the decoupled sound source was calculated. .

7. The passive localization method for deep-sea horizontal array acoustic sources based on high-precision azimuth estimation according to claim 6, characterized in that, Step 6 specifically includes: The estimated pitch angle of the sound source Substituting into the theoretical time delay calculation formula, calculate the depth of different assumed sound sources. Corresponding theoretical delay : ； in, For receiving depth The corresponding speed of sound, For receiving depth, Let z be the speed of sound at depth z. For depth, satisfy .

8. The passive localization method for deep-sea horizontal array acoustic sources based on high-precision azimuth estimation according to claim 7, characterized in that, Step 7 specifically includes: High-precision azimuth estimation of sound source The beam output results at the specified location are subjected to frequency domain mean-reduction processing, and the mean-reduction beam output spectrum is obtained. satisfy: ； in, For frequency point index, Frequency point index Frequency at that location To handle the total number of frequency points within the frequency band, For high-precision sound source azimuth angle estimation value The beam output sound field intensity; Beam output spectrum after mean removal Perform an inverse Fourier transform to obtain the measured arrival time delay spectrum of the sound source. : ； in For arrival delay.

9. The passive localization method for deep-sea horizontal array acoustic sources based on high-precision azimuth estimation according to claim 8, characterized in that, Step 8 specifically includes: Extracting the measured arrival time delay spectrum of the sound source The time delay corresponding to the mid-peak value is used as the measured dominant path time delay of the sound source. The measured time delay of the dominant path of the sound source Theoretical time delay corresponding to different assumed sound source depths Perform matching and construct the cost function. , where the cost function satisfy: , The arrival delay spectrum after matching is represented; the assumed sound source depth that minimizes the cost function is selected as the estimated actual sound source depth. : ； in, Assuming the depth of the sound source, Assuming the depth of the sound source The corresponding cost function, Represents constraint symbols.

10. A passive localization system for a deep-sea horizontal array acoustic source based on high-precision azimuth estimation, comprising: The signal sampling module is used to perform time-domain sampling of sound source signals in the deep sea through a horizontal array, select reference array elements, and estimate the earliest arrival time of the signal based on the time-domain waveform of the reference array elements. The frequency domain processing and phase compensation module is used to perform Fourier transform on the time domain sound source signals received by each element of the horizontal array to obtain array frequency domain data, and to perform phase compensation on the frequency domain data using the earliest arrival time of the signal. The fringe slope search module is used to construct a fringe slope cost function that varies with frequency, perform a blind search on the fringe slope, and extract the fringe slope value that maximizes the beam output as the fringe slope reference value. An angle estimation module is used to construct broadband sound pressure frequency shift data based on the fringe slope reference value, and to perform beamforming using the broadband sound pressure frequency shift data to obtain a high-precision sound source azimuth angle estimate. Furthermore, conventional beamforming is performed on the frequency domain data after phase compensation to obtain the solid angle estimate of the coupled azimuth and elevation angles; The pitch angle decoupling module is used to obtain the pitch angle estimate of the sound source by utilizing the high-precision azimuth angle estimate and solid angle estimate of the sound source; The theoretical time delay calculation module is used to calculate the theoretical time delay corresponding to different assumed sound source depths in the deep sea using the estimated sound source pitch angle; The measured time delay spectrum acquisition module is used to obtain the measured arrival time delay spectrum of the sound source by utilizing the broadband beam output results at the high-precision sound source azimuth angle estimation value. and The sound source depth estimation module is used to extract the peak value corresponding to the measured arrival time delay spectrum of the sound source, match the peak value corresponding to the theoretical time delay corresponding to different assumed sound source depths, and estimate the actual depth of the sound source based on the matching results.

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