A cross-zone sound source localization method using dual hydrophones in deep-sea environment

Abstract

The present invention discloses a cross-sound zone sound source localization method using dual hydrophones in a deep-sea environment, comprising: step 1: using the dual hydrophones to receive broadband signals radiated by a sound source in a specified sea area, and simultaneously using other hydroacoustic equipment to obtain environmental parameters of the sea area; step 2: using a time-spectral energy accumulation method to extract the arrival times of different sound lines from the received signal of one of the hydrophones, and estimating two multipath time delay differences; step 3: using a sound field calculation model BELLHOP to simulate two multipath time delay differences in different sound zones when the sound source is at different grid virtual points; step 4: calculating a cost function, and estimating the position of a target sound source; step 5: repeating steps 2 and 4 for the signal received by another hydrophone, and estimating the position of the target sound source; and step 6: performing a similarity analysis on four estimation results obtained by positioning the two hydrophones, and taking the average of the two estimation results with the greatest similarity as the final sound source position estimation result.

Description

Technical Field

[0001] The present invention relates to the fields of underwater acoustic engineering, ocean engineering, sonar technology, and in particular to a cross-acoustic zone sound source positioning method using dual hydrophones in a deep-sea environment. Background Art

[0002] In deep-sea environments, signals received at different distances follow different propagation paths, forming distinct sound zones. Using multipath structural parameters (such as time-domain multipath delay differences, frequency-domain interference structures, and spatial multipath arrival angles) in different sound zones to localize sound sources is a current research hotspot in underwater acoustics. While sound source localization methods for different sound zones have been extensively studied, research on cross-sound zone sound source localization remains relatively scarce. A major limitation to this development is the misjudgment of sound zones due to the similarity of multipath structures within these zones. Consequently, most current sound source localization methods are applicable to a single sound zone, significantly reducing the scope of target positioning.

[0003] In order to obtain the multipath characteristic parameters of the sound field, the commonly used receiving methods include horizontal array receiving and vertical array receiving. However, when using array receiving, there are problems such as difficulty in deployment, array calibration and array element synchronization. Therefore, many scholars have begun to try to reduce the number of array elements and use dual hydrophone arrays or single hydrophones for positioning. For example, the method in reference [1] ("Passive localization in the deep ocean based on cross-correlation function matching", published in "J.Acoust.Soc.Am." Vol. 139, No. 6, June 2016, starting page EL196) uses a dual hydrophone array to receive the sound source signal and performs cross-correlation function matching based on the arrival time of the sound lines received by the two hydrophones to estimate the sound source position. However, this method is only applicable to the direct sound area and cannot be applied to sound source positioning in other sound areas. To achieve cross-sound zone sound source positioning, it is necessary to utilize the common features between different sound zones. For example, reference [2] (“Depth estimation for broadband sources with a vertical line array in deep water”, published in J.Acoust.Soc.Am., Vol. 155, No. 2, February 2024, starting at page 1103) provides a theoretical formula for calculating multipath delay difference, and this formula only depends on the multipath arrival angle and sound velocity profile, so it can be applied to different sound zones. The positioning method in this document mainly uses a vertical array to obtain the multipath arrival angle and multipath delay difference of the target, and then matches them with the multipath delay difference calculated by the theoretical formula to achieve sound source depth estimation in the direct sound zone and the first shadow zone. However, this method only gives the sound source depth estimation result and cannot be used for sound source distance estimation, and still needs to overcome the problems faced by array reception. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings of the prior art and proposes a method for cross-sound zone sound source localization using dual hydrophones in a deep-sea environment. The method is applicable to both the direct sound zone and the shadow zone.

[0005] To achieve the above objectives, the present invention proposes a method for cross-sound zone sound source localization using dual hydrophones in a deep-sea environment, comprising:

[0006] Step 1: Use dual hydrophones to receive broadband signals radiated from sound sources in a designated sea area, and simultaneously use other hydroacoustic equipment to obtain environmental parameters of the sea area;

[0007] Step 2: Use the time-spectral energy accumulation method to extract the arrival times of different sound lines from the received signal of one of the hydrophones and estimate the difference in the two multipath delays;

[0008] Step 3: Use the sound field calculation model BELLHOP to simulate the two multipath delay differences in different sound zones when the sound source is at different grid virtual points;

[0009] Step 4: Calculate the cost function and estimate the target sound source position;

[0010] Step 5: Repeat steps 2 to 4 for the signal received by another hydrophone to estimate the location of the target sound source;

[0011] Step 6: Perform similarity analysis on the four estimation results obtained by the two hydrophone positioning, and take the average of the two estimation results with the greatest similarity as the final sound source position estimation result.

[0012] Preferably, the placement positions of the dual hydrophones meet set requirements from the sea surface and the seabed to ensure that the sound signals reflected by the sea surface or the seabed can be received; the distance between the dual hydrophones meets set requirements to ensure that the signals received by the two hydrophones are different.

[0013] Preferably, the other equipment in step 1 includes:

[0014] Temperature, salinity, and depth meters to obtain seawater sound velocity profiles; and

[0015] Multi-beam systems or nautical charts are used to obtain information such as sea depth and topography.

[0016] Preferably, the step 2 comprises:

[0017] Perform a segmented short-time Fourier transform on the original acoustic signal received by the hydrophone to obtain the signal's time-frequency spectrum STFT(f,t);

[0018] The spectrum energy within the signal bandwidth in the time-spectrum diagram STFT(f,t) is accumulated to obtain the curve S(t) showing the change of signal frequency domain energy over time:

[0019]

[0020] Where f and t represent frequency and time respectively, f high and f low Respectively represent the upper and lower bounds of the broadband sound source frequency;

[0021] Normalize the curve S(t) showing the change of signal frequency domain energy over time, extract the time corresponding to the first maximum value and the time corresponding to the maximum amplitude from the first cluster of signals, and extract the time corresponding to the maximum amplitude from the second cluster of signals;

[0022] If the sound source is in the direct sound zone, the above three moments correspond to the arrival times of the direct sound ray, the sea surface reflected sound ray and the seabed reflected sound ray respectively;

[0023] If the sound source is in the shadow area, the above three moments correspond to the arrival times of the seabed reflection sound line, the sea surface-seabed reflection sound line, and the seabed-sea surface reflection sound line respectively;

[0024] The time difference between the first moment and the second moment is recorded as The time difference between the first moment and the third moment is recorded as In this way, two multipath delay differences are estimated from the received signal.

[0025] Preferably, the step 3 comprises:

[0026] Divide the area where the sound source to be located may exist into a grid, and each grid point is a grid virtual point; the depth and distance of each grid virtual point are recorded as z and r respectively;

[0027] According to the range of the direct sound zone and the shadow zone at different sound source depths, the two delay differences of the direct sound zone are simulated and calculated respectively. and And the two delay differences in the shadow area and Among them, when the sound reaches the direct sound area, the two delay differences are and They represent the time delay difference between the direct sound line and the sound line reflected from the sea surface, and the time delay difference between the direct sound line and the sound line reflected from the seabed. In the shadow area, the two delay differences

[0028] and They represent the time delay difference between the seabed reflected sound line and the sea surface-seabed reflected sound line, and the time delay difference between the seabed sound line and the seabed-sea surface reflected sound line respectively.

[0029] Preferably, step 4 includes:

[0030] According to the two multipath delay differences obtained in step 2 and The two delay differences of the direct sound zone obtained in step 3 are and And the two delay differences in the shadow area and Substitute the following formulas to calculate the corresponding cost function L(z,r):

[0031]

[0032] According to the obtained cost function of the direct sound area and the cost function of the shadow area, the minimum value of each cost function is selected respectively, thereby obtaining the positioning result of the direct sound area and the positioning result of the shadow area.

[0033] Preferably, step 6 includes:

[0034] Perform similarity analysis on the four positioning results obtained by the two hydrophones, and take the average of the two positioning results with the greatest similarity as the final sound source position estimation result

[0035] The similarity S(i,j) is obtained according to the following formula:

[0036]

[0037] in, and denote the i-th estimated target depth and distance respectively, and Denote the j-th estimated target depth and distance, respectively, i≠j; i,j∈{1,2,3,4}; where subscripts 1 and 2 represent the positioning results of the first hydrophone using the simulated time delay difference in the direct sound zone and the shadow zone, respectively; subscripts 3 and 4 represent the positioning results of the second hydrophone using the simulated time delay difference in the direct sound zone and the shadow zone, respectively;

[0038] When S(i,j) is 1, it means that the two positioning results are completely consistent;

[0039] When S(i,j)∈(0,1), it means that the two positioning results are different;

[0040] When S(i,j) is 0, it means that at least one positioning result does not exist;

[0041] Select the average of the two results with the largest S(i,j) as the depth estimation result of the final target And the distance estimation results

[0042] Compared with the prior art, the advantages of the present invention are:

[0043] The method of the present invention utilizes dual hydrophones to receive sound source signals, which, to a certain extent, alleviates problems encountered during array reception, such as array calibration and array element synchronization. For a single sound zone, the method performs joint matching based on two multipath time delay differences, eliminating the ambiguity of single time delay positioning results. Furthermore, the method addresses the problem of misjudgment of sound zones by using the positioning results of dual hydrophones for comprehensive analysis to screen out the correct sound source position, thereby achieving cross-sound zone sound source positioning. The method can be applied to both direct sound zones and shadow zones for sound source depth and distance estimation. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a flow chart of a method for cross-acoustic zone sound source localization using dual hydrophones in a deep-sea environment according to the present invention;

[0045] Figure 2are the sound velocity profile and seabed topography measured in the offshore experiment and the seabed parameters used in the simulation in the embodiment of the present invention;

[0046] FIG3( a ) is a waveform of the original signal received by the hydrophone at a depth of 1806 m according to an embodiment of the present invention;

[0047] FIG3( b ) is a time-frequency spectrum obtained by using a piecewise short-time Fourier transform according to an embodiment of the present invention;

[0048] FIG3( c ) is a curve showing the variation of frequency domain energy over time and the extraction result of multipath sound ray arrival time obtained after accumulating spectrum energy in an embodiment of the present invention;

[0049] FIG4( a ) shows the cost function and sound source position estimation result calculated by simulating the delay difference of the direct sound zone when the receiving depth is 1806 m in an embodiment of the present invention;

[0050] FIG4( b ) shows the cost function and the sound source position estimation result calculated by using the shadow area simulation delay difference when the receiving depth is 1806 m in an embodiment of the present invention;

[0051] FIG4( c ) is a cost function and sound source position estimation result calculated using the direct sound zone simulation delay difference when the receiving depth is 2885 m in an embodiment of the present invention;

[0052] FIG4( d ) is a cost function and a sound source position estimation result calculated by simulating the time delay difference in the shadow sound zone when the receiving depth is 2885 m in an embodiment of the present invention;

[0053] FIG5( a ) is a diagram showing the sound source distance estimation results for different sound zones in an offshore experiment according to an embodiment of the present invention;

[0054] FIG5( b ) is a diagram showing the sound source depth estimation results for different sound zones in an offshore experiment according to an embodiment of the present invention;

[0055] FIG5( c ) is a diagram showing the relative error of the sound source distance estimation in different sound zones in the offshore experiment according to an embodiment of the present invention;

[0056] FIG5( d ) shows the relative error of the sound source depth estimation in different sound zones in the offshore experiment according to an embodiment of the present invention. DETAILED DESCRIPTION

[0057] The present invention proposes a cross-acoustic zone sound source localization method using dual hydrophones in a deep-sea environment. First, a dual hydrophone buoy system is deployed at an appropriate location in the deep-sea environment to receive broadband sound pressure radiated by the sound source. The deployment location needs to be a certain distance from the sea surface or seabed in order to receive the sound signals transmitted through the sea surface and reflected by the seabed. At the same time, the depths of the two hydrophones cannot be too close, otherwise the received signals will lack differentiation. Secondly, a time-frequency spectrum energy accumulation method is used to extract the multipath delay difference from the received signal. The specific operation is to perform a segmented short-time Fourier transform on the original received signal to obtain a signal time-frequency spectrum diagram. Then, the spectrum energy within the signal bandwidth range in the spectrum is accumulated to obtain a spectrum energy change curve over time. The time corresponding to the maximum value is extracted from it, which is the relative time when different sound lines arrive at the receiving point, and then the multipath delay difference is calculated. A simulation model was used to calculate the multipath delay differences between the direct sound zone and the shadow zone. The delay differences extracted from the received signal and the theoretically calculated delay differences were then applied to cost functions. The cost functions were minimized to estimate the sound source location. Because the delays in both sound zones were used, the same hydrophone produced two localization results. The same operation was performed on another hydrophone, resulting in a total of four sound source location estimates. These four localization results were analyzed for similarity, and the average of the two most similar results was taken as the final sound source location estimate, eliminating erroneous results caused by misjudgment of the sound zone.

[0058] This method can realize the sound source positioning of deep-sea direct sound zone and shadow zone through dual hydrophones. The system complexity is low and easy to implement. It overcomes the limitation that the original positioning method is only applicable to a single sound zone, realizes deep-sea cross-sound zone sound source positioning, and improves the range of sound source positioning.

[0059] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0060] Example

[0061] The embodiment of the present invention proposes a method for cross-sound zone sound source localization using dual hydrophones in a deep-sea environment, and the implementation process is divided into the following steps: Figure 1 As shown:

[0062] Step 1: Deploy a dual-hydrophone buoy system at a suitable location in the designated sea area to record the broadband signal radiated by the sound source, and use other hydroacoustic equipment to obtain the environmental parameters of the sea area.

[0063] This example uses two hydrophones at receiving depths of 1806m and 2885m on a vertical array in a certain East Indian Ocean sea trial as an example. The hydrophone sampling rate is 16kHz. The sound source of the sea trial experiment is a broadband explosion sound source with a calibration depth of 50m and 200m. The explosion sound source is thrown at different distances from the sound source on the same survey line. In the experiment, the seawater sound velocity profile is obtained by a temperature-salinity-depth meter (CTD), and the seawater depth, seabed topography and other information are obtained by a multi-beam system or a nautical chart. The results are as follows: Figure 2 The following example demonstrates the complete sound source localization method using a signal with a source depth of 200m and a source distance of 6.367km.

[0064] Step 2: Use the time-spectral energy accumulation method to extract the arrival times of different sound lines from the received signal of a single hydrophone and estimate the two multipath delay differences.

[0065] Figure 3(a) 、 3(b) Figure 3(c) shows the specific process of extracting the arrival time of multipath sound lines from the received signal using the time-frequency spectrum energy accumulation method. Figure 3(a) corresponds to the original sound signal received by the hydrophone at 1806 m. The received signal shown in Figure 3(a) is segmented and short-time Fourier transformed to obtain the signal's time-frequency spectrum STFT(f,t), as shown in Figure 3(b). Then, the spectrum energy within the signal bandwidth in the time-frequency spectrum is accumulated to obtain the curve S(t) showing the change of signal frequency domain energy over time:

[0066]

[0067] Where f and t represent frequency and time, f high and f low Respectively represent the upper and lower bounds of the broadband sound source frequency. In this embodiment, the sound source is an explosion sound source, and there are signals in the full frequency band. Therefore, the upper and lower bounds of the frequency are 8kHz and 0Hz respectively. The normalized results after accumulation are shown in Figure 3(c). The moments corresponding to the first maximum value and the maximum amplitude are extracted from the first cluster of signals (between 5.3s and 5.5s), marked with red solid lines and green solid lines respectively. The moment corresponding to the maximum amplitude is extracted from the second cluster of signals (between 6.8s and 7s), marked with blue solid lines. If the sound source is in the direct sound zone, these three moments (red line, green line, blue line in order) correspond to the arrival times of the direct (D) sound line, the sea surface reflection (SR) sound line and the seabed reflection (BR) sound line respectively; if the sound source is in the shadow zone, these three moments correspond to the arrival times of the seabed reflection sound (BR) line, the sea surface-seabed reflection (SBR) sound line and the seabed-sea surface reflection (BSR) sound line respectively. The time difference between the first moment and the second moment is then recorded as The time difference between the first moment and the third moment is recorded as In this way, two multipath delay differences are estimated from the received signal.

[0068] Step 3: Use the sound field calculation model BELLHOP to simulate two multipath delays in different sound zones when the sound source is at different grid virtual points.

[0069] Using the measured environmental parameters and the receiving depth of the hydrophone, the sound field model BELLHOP is used for calculation to simulate two multi-path time delays in different sound zones when the sound source is at different grid virtual points. The area where the sound source to be located may exist is grid-divided, and each grid point is the above-mentioned grid virtual point. It is generally believed that the depth range of the sound source is 0-300m and the distance range is 0-50km. Taking into account the calculation accuracy and calculation speed, it is recommended to set the depth grid step to 1m and the distance grid step to 0.01km; the depth and distance of each grid virtual point are recorded as z and r. Then, according to the range of the direct sound zone and the shadow zone at different sound source depths, the two time delays in the two sound zones are simulated and calculated respectively. and For the direct sound area, the two types of time delay differences are the time delay difference between the direct sound line and the sound line reflected from the sea surface, and the time delay difference between the direct sound line and the sound line reflected from the seabed; for the shadow area, the two types of time delay differences are the time delay difference between the sound line reflected from the seabed and the sound line reflected from the sea surface to the seabed, and the time delay difference between the sound line reflected from the seabed to the sea surface.

[0070] Step 4: Calculate the cost function and estimate the target sound source position.

[0071] The cost function is used to calculate the output value of the cost function at each grid simulation point. The grid point position where the cost function takes the minimum value is the sound source position estimation result. The cost function is as follows:

[0072]

[0073] Since it is unknown which sound zone the sound source belongs to, the delay differences simulated in the direct sound zone and the shadow zone are used for positioning respectively. The multipath delay difference extracted from the received signal and the multipath delay difference calculated by simulation are substituted into the cost function for calculation. That is, the multipath delay difference extracted from the received signal in step 2 and the two delays of the direct sound zone calculated by simulation in step 3 are substituted into the cost function respectively. The multipath delay difference extracted from the received signal in step 2 and the two delays of the shadow zone calculated by simulation in step 3 are substituted into the cost function respectively. The results are as follows: Figure 4(a) and 4(b) As shown in the figure, the grid point corresponding to the minimum value of the cost function is also the intersection of the two fuzzy curves, which is the positioning result. It can be seen that two positioning results are obtained: one is the correct result, and the other is an incorrect result caused by misjudging the sound zone by using the delay difference of the wrong sound zone for matching. In this case, it is impossible to determine which result is correct based on a single hydrophone. The positioning results of the two hydrophones need to be analyzed together.

[0074] Step 5: Repeat steps 2 to 4 for the signal received by another hydrophone to estimate the location of the target sound source.

[0075] Using steps 2 to 4 to process the signal received by another depth hydrophone, including extracting the delay difference from the signal, calculating the simulated delay difference, and matching the cost function for positioning, two positioning results will also be obtained, such as Figure 4(c) and 4(d) The results of sound source localization using a hydrophone at a receiving depth of 2885m.

[0076] Step 6: Perform similarity analysis on the four positioning results obtained by the two hydrophones, and take the average of the two positioning results with the greatest similarity as the final sound source position estimation result.

[0077] Perform similarity analysis on the four positioning results obtained in steps 2 to 5. Here, the similarity parameter is used to characterize the consistency of the two results, where the similarity is defined as:

[0078]

[0079] Where S(i,j) is the similarity between the i-th and j-th results, and is the estimated target depth and distance, subscripts 1 and 2 represent the positioning results of the first hydrophone using the simulated delay difference in the direct sound zone and the shadow zone respectively, and subscripts 3 and 4 represent the positioning results of the second hydrophone using the simulated delay difference in the direct sound zone and the shadow zone respectively. Then the average of the two results with the largest similarity is selected as the final positioning result, that is,

[0080]

[0081] in and Represent the final target depth and distance estimation results respectively. When the two positioning results are completely consistent, the similarity is 1; when the two positioning results are different, the similarity is between 0 and 1; when one of the positioning results does not exist, it is considered that the two results are infinitely different and the similarity is 0. The similarity of the positioning results is calculated as S(1,2)=0.901、S(1,3)=0.996、S(1,4)=0、S(2,3)=0.905、S(2,4)=0、S(3,4)=0, so the positioning results with the greatest similarity are the first and third results, that is, Figure 4(a) and 4(c) The results shown in the figure take the average of the two positioning results to obtain the final target position estimation result, with a depth of 204m and a distance of 6.475km, which are close to the actual target position.

[0082] The above steps are used to process the sound source signals at other distances and depths, and the final estimated target position and relative error results are as follows: Figure 5(a) 、 5(b) , 5(c), and 5(d). Figure 4(a) shows the cost function and sound source position estimation results calculated using the simulated time delay difference in the direct sound zone at a receiving depth of 1806m; Figure 4(b) shows the cost function and sound source position estimation results calculated using the simulated time delay difference in the shadow zone at a receiving depth of 1806m; Figure 4(c) shows the cost function and sound source position estimation results calculated using the simulated time delay difference in the direct sound zone at a receiving depth of 2885m; Figure 4(d) shows the cost function and sound source position estimation results calculated using the simulated time delay difference in the shadow zone at a receiving depth of 2885m. As shown in Figure 5(a), the sound source distance estimation results for different sound zones in the offshore experiment; Figure 5(b) shows the sound source depth estimation results for different sound zones in the offshore experiment; Figure 5(c) shows the relative error of the sound source distance estimation for different sound zones in the offshore experiment; and Figure 5(d) shows the relative error of the sound source depth estimation for different sound zones in the offshore experiment. As can be seen from the figure, the estimated sound source position and the actual sound source position are basically consistent, whether in the direct sound zone or the shadow zone; the relative error in distance is basically less than 5%, and the large relative error in close distance (within 2km) is mainly caused by the small distance base. In fact, the absolute error in close distance is less than 300m; the relative error of the sound source depth estimation is mostly within 15%, and the error at several individual distances is close to 20%. The average relative error of the depth estimation is 6.95%. Measured data verification shows that the method of the present invention can effectively estimate the sound source position in the deep-sea direct sound zone and shadow zone, and can realize cross-sound zone sound source positioning in deep-sea environments.

[0083] 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 method for cross-sound zone sound source localization using dual hydrophones in a deep-sea environment, comprising: Step 1: Use dual hydrophones to receive broadband signals radiated from sound sources in a designated sea area, and simultaneously use other hydroacoustic equipment to obtain environmental parameters of the sea area; Step 2: Use the time-spectral energy accumulation method to extract the arrival times of different sound lines from the received signal of one of the hydrophones and estimate the difference in the two multipath delays; Step 3: Use the environmental parameters to simulate the two multipath delay differences in different sound zones when the sound source is at different grid virtual points through the sound field calculation model BELLHOP; Step 4: Calculate the cost function and estimate the target sound source position; Step 5: Repeat steps 2 to 4 for the signal received by another hydrophone to estimate the location of the target sound source; Step 6: Perform similarity analysis on the four estimation results obtained by the two hydrophone positioning, and take the average of the two estimation results with the greatest similarity as the final sound source position estimation result; Other equipment in step 1 include: Temperature, salinity, and depth meters to obtain seawater sound velocity profiles; and Multi-beam systems or nautical charts to obtain sea depth and topographic information; The step 4 comprises: According to the two multipath delay differences obtained in step 2 and The two delay differences of the direct sound zone obtained in step 3 are and And the two delay differences in the shadow area and Substitute the following formulas to calculate the corresponding cost function L(z,r): According to the obtained cost function of the direct sound area and the cost function of the shadow area, the minimum value of each cost function is selected to obtain the positioning result of the direct sound area and the positioning result of the shadow area; The step 6 comprises: The similarity S(i,j) is obtained according to the following formula: in, and denote the i-th estimated target depth and distance respectively, and Denote the j-th estimated target depth and distance, respectively, i≠j; i,j∈{1,2,3,4}; where subscripts 1 and 2 represent the positioning results of the first hydrophone using the simulated time delay difference in the direct sound zone and the shadow zone, respectively; subscripts 3 and 4 represent the positioning results of the second hydrophone using the simulated time delay difference in the direct sound zone and the shadow zone, respectively; When S(i,j) is 1, it means that the two positioning results are completely consistent; When S(i,j)∈(0,1), it means that the two positioning results are different; When S(i,j) is 0, it means that at least one positioning result does not exist; Select the average of the two results with the largest S(i,j) as the depth estimation result of the final target And the distance estimation results 2. The method for cross-sound zone sound source localization using dual hydrophones in a deep-sea environment according to claim 1, characterized in that: The deployment positions of the dual hydrophones meet the set requirements from the sea surface and the seabed to ensure that the sound signals reflected by the sea surface or the seabed can be received; the distance between the dual hydrophones meets the set requirements to ensure that the signals received by the two hydrophones are different.

3. The method for cross-sound zone sound source localization using dual hydrophones in a deep-sea environment according to claim 1, characterized in that: The step 2 includes: Perform a segmented short-time Fourier transform on the original acoustic signal received by the hydrophone to obtain the signal's time-frequency spectrum STFT(f,t); The spectrum energy within the signal bandwidth in the time-spectrum diagram STFT(f,t) is accumulated to obtain the curve S(t) showing the change of signal frequency domain energy over time: Where f and t represent frequency and time respectively, f high and f low Respectively represent the upper and lower bounds of the broadband sound source frequency; Normalize the curve S(t) showing the change of signal frequency domain energy over time, extract the time corresponding to the first maximum value and the time corresponding to the maximum amplitude from the first cluster of signals, and extract the time corresponding to the maximum amplitude from the second cluster of signals; If the sound source is in the direct sound zone, the above three moments correspond to the arrival times of the direct sound ray, the sea surface reflected sound ray and the seabed reflected sound ray respectively; If the sound source is in the shadow area, the above three moments correspond to the arrival times of the seabed reflection sound line, the sea surface-seabed reflection sound line, and the seabed-sea surface reflection sound line respectively; The time difference between the first moment and the second moment is recorded as The time difference between the first moment and the third moment is recorded as In this way, two multipath delay differences are estimated from the received signal.

4. The method for cross-sound zone sound source localization using dual hydrophones in a deep-sea environment according to claim 3, characterized in that: The step 3 comprises: Divide the area where the sound source to be located may exist into a grid, and each grid point is a grid virtual point; the depth and distance of each grid virtual point are recorded as z and r respectively; According to the range of the direct sound zone and the shadow zone at different sound source depths, the two delay differences of the direct sound zone are simulated and calculated respectively. and And the two delay differences in the shadow area and Among them, when the sound reaches the direct sound area, the two delay differences are and They represent the time delay difference between the direct sound line and the sound line reflected from the sea surface, and the time delay difference between the direct sound line and the sound line reflected from the seabed. In the shadow area, the two delay differences and They represent the time delay difference between the seabed reflected sound line and the sea surface-seabed reflected sound line, and the time delay difference between the seabed sound line and the seabed-sea surface reflected sound line respectively.

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