Water surface target passive distance measurement method based on vertical double hydrophones, storage medium and equipment

Abstract

The invention discloses a water surface target passive ranging method based on vertical double hydrophones, a storage medium and equipment, and belongs to the technical field of underwater acoustic detection and array signal processing. The problems that an existing water surface target distance measurement method is small in application range and a geometric structure used for distance measurement is complex are solved. The hydrophone is arranged close to the seabed and is mainly used for positioning a target directly reaching a sound area, the hydrophone and the target are vertically arranged, and only a depth difference exists between the hydrophone and the target, so that the target can be accurately positioned through self-correlation operation of signals received by the hydrophone. The time delay between the deep sea direct sound and the seabed reflected sound can be extracted by using the obtained hydrophone autocorrelation function, an equation set is established by using the time delay between the deep sea direct sound and the seabed reflected sound, and the horizontal distance between the hydrophone and the water surface target is obtained by solving the equation set. By means of the distance measuring method, the water surface target can be detected in real time, and the distance measuring result of the water surface target is obtained. The method can be applied to water surface target distance measurement.

Description

Technical Field

[0001] The invention belongs to the technical field of underwater acoustic detection and array signal processing, and in particular relates to a passive ranging method for surface targets based on vertical dual hydrophones, a storage medium and a device. Background Art

[0002] At present, the demand for passive positioning technology of underwater targets is becoming more and more urgent, and it is gradually developing towards deep-sea passive detection methods. There is an obvious multi-path structure in the propagation of sound waves in water. The time delay of different paths reaching the hydrophone is closely related to the geometric structure between the sound source position and the hydrophone. For surface targets, the time delay difference between the direct wave and the sea surface reflection wave is very small and difficult to extract; while the seabed terrain is flat in most cases, and the seabed reflection structure is relatively stable. However, there are relatively few studies on passive positioning using seabed acoustic reflections. The following research has been conducted using seabed reflections for passive positioning: Reference 1 (Xu Jialin, Guo Lianghao, Ren Yun. Multipath delay difference analysis of deep-sea seabed acoustic reflection zone and near-sea surface sound source positioning [J]. Acta Acoustics, 2023, 48(04): 618-631. DOI: 10.15949 / j.cnki.0371-0025.2023.04.013.) mainly studied the four sound lines in the seabed acoustic reflection zone. According to the time when the four sound line paths in the seabed acoustic reflection zone arrive at the receiving point, six different sound line arrival delay differences can be obtained. The delay difference contains the sound source location information. The distance and depth of the sound source are estimated by extracting information from the six delay differences, but the geometric structure is relatively complex. Reference 2 (Sun Dajun, Lu Mingyang, Mei Jidan, et al. Passive positioning based on generalized Radon transform of seabed reflection delay [J]. Acta Acoustica Sinica, 2023, 48(06): 1142-1153.) proposed a target parameter estimation method based on generalized Radon transform. The idea of ​​Radon transform is introduced through the geometric mathematical model between direct sound and seabed reflection sound, and the motion parameter estimation of the surface uniform speed direct target is realized through two hydrophones. However, it is only applicable to the positioning of direct moving targets, and is not applicable to the positioning of non-direct moving targets. Therefore, the scope of application of the positioning method is relatively small.

[0003] In summary, the existing target positioning methods have limitations to varying degrees in practical applications. Therefore, the existing target positioning technology still cannot meet the ranging requirements of surface targets. Therefore, proposing a new surface target ranging method is an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to solve the problems of small application range and complex geometric structure of existing surface target ranging methods, and propose a surface target passive ranging method based on vertical dual hydrophones, storage medium and equipment.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: a passive ranging method for surface targets based on vertical dual hydrophones, the method specifically comprising the following steps:

[0006] Step 1: performing autocorrelation operation on the received signals of the two hydrophones respectively to obtain the autocorrelation functions of the two hydrophones, and the line connecting the two hydrophones is perpendicular to the water surface;

[0007] Step 2: extracting the seabed reflection delay τ1 according to the autocorrelation function of the first hydrophone, and extracting the seabed reflection delay τ2 according to the autocorrelation function of the second hydrophone;

[0008] Step 3: Establish a set of equations for calculating the horizontal distance between the hydrophone and the surface target at time t according to the seabed reflection delay τ1 and the seabed reflection delay τ2;

[0009] Step 4: Solve the equations established in step 3 to obtain the horizontal distance between the surface target and the hydrophone;

[0010] Step 5: Execute steps 1 to 4 for the signal received by the hydrophone at each moment to obtain the distance course measurement result for the surface target.

[0011] Furthermore, the autocorrelation operation is performed on the received signals of the two hydrophones respectively, specifically:

[0012] The signal g1(t) received by the first hydrophone at time t is expressed as:

[0013]

[0014] Where h1(t) represents the impulse response function of the first hydrophone channel at time t, represents convolution, s(t) represents the signal emitted by the target at time t, and n1(t) represents the noise signal received by the first hydrophone at time t;

[0015] The signal g2(t) received by the second hydrophone at time t is expressed as:

[0016]

[0017] Where h2(t) represents the impulse response function of the second hydrophone channel at time t, represents convolution, n2(t) represents the noise signal received by the second hydrophone at time t;

[0018] Then the autocorrelation functions of the first hydrophone and the second hydrophone at time t are expressed as:

[0019] R1(τ)=E[g1(t)g1(t-τ)]

[0020] R2(τ)=E[g2(t)g2(t-τ)]

[0021] Where R1(τ) represents the autocorrelation function of the first hydrophone, R2(τ) represents the autocorrelation function of the second hydrophone, and E[·] represents the expectation.

[0022] Furthermore, the impulse response function h1(t) of the first hydrophone channel at time t is:

[0023]

[0024] Where N is the number of eigenvalues ​​reaching the hydrophone, a i represents the amplitude of the i-th eigenvalue, τ 1,i represents the time delay of the i-th eigenwave reaching the first hydrophone, i = 0 represents the direct wave, and δ(t) is the unit impulse response;

[0025] The impulse response function h2(t) of the second hydrophone channel at time t is:

[0026]

[0027] Among them, τ 2,i represents the time delay of the i-th eigenvalue ray reaching the second hydrophone.

[0028] Furthermore, the equation group for calculating the horizontal distance between the hydrophone and the surface target at time t is established according to the seabed reflection delay τ1 and the seabed reflection delay τ2, specifically:

[0029]

[0030] Wherein, H is the equivalent reflection depth of the seabed, r is the horizontal distance between the surface target and the hydrophone, H1 is the depth of the first hydrophone, H2 is the depth of the second hydrophone, h is the source depth of the noise signal radiated by the surface target, c is the equivalent sound speed in water, τ1 is the seabed reflection delay of the first hydrophone, and τ2 is the seabed reflection delay of the second hydrophone.

[0031] Furthermore, in step 4, the multivariate Newton iteration method is used to solve the system of equations established in step 3.

[0032] Furthermore, the specific process of step 4 is as follows:

[0033] Step 41: Initialize the number of iterations k = 1 and initialize X 0 =[r0,H0] T, H0 represents the initialization value of the equivalent reflection depth of the seabed, r0 represents the initialization value of the horizontal distance between the hydrophone and the surface target;

[0034] Step 42: According to X k Calculate X k+1 =[r k+1 ,H k+1 ] T :

[0035]

[0036] Where G is the Jacobian matrix, Represents the iteration increment;

[0037] Step 43: Determine whether the iteration increment satisfies Among them, ε is the set threshold, ||·||2 means calculating the 2-norm;

[0038] If satisfied, then H k+1 As an estimate of the depth of the seafloor reflection point, r k+1 As an estimate of the horizontal distance between the surface target and the hydrophone;

[0039] If not satisfied, set k=k+1 and return to step 42.

[0040] Furthermore, the Jacobian matrix G is:

[0041]

[0042] A computer storage medium stores at least one instruction, and the at least one instruction is loaded and executed by a processor to implement a passive ranging method for surface targets based on vertical dual hydrophones.

[0043] A passive ranging device for a surface target based on vertical dual hydrophones, the device comprising a processor and a memory, the memory storing at least one instruction, the at least one instruction being loaded and executed by the processor to implement a passive ranging method for a surface target based on vertical dual hydrophones.

[0044] The beneficial effects of the present invention are:

[0045] The hydrophone in the present invention is arranged close to the seabed, mainly to locate the target in the direct sound zone, and because the arrangement mode is vertical, the only difference between the two is the depth. By performing autocorrelation operation on the hydrophone receiving signal, the time delay between the deep-sea direct sound and the seabed reflected sound can be extracted by using the obtained hydrophone autocorrelation function, and the time delay between the deep-sea direct sound and the seabed reflected sound is used to establish an equation group, and then the horizontal distance between the hydrophone and the surface target is obtained by solving the equation group. The distance measurement method of the present invention can be used to detect the surface target in real time and obtain the distance measurement result of the surface target.

[0046] The method of the present invention only requires two vertically arranged hydrophones to be implemented, and the ranging result can be obtained through a simple geometric ranging structure. Moreover, there is no need to restrict the surface target to make a straight-line movement, and the ranging can still be achieved in a non-straight-line movement, and the application range is wide; and the method of the present invention has a small amount of calculation, which effectively ensures the real-time performance of the ranging. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a flow chart of a method for passive ranging of surface targets based on vertical dual hydrophones of the present invention;

[0048] Figure 2 is a schematic diagram of target motion;

[0049] Figure 3 It is a schematic diagram of the arrival of direct sound waves and sound waves reflected from the seabed;

[0050] Figure 4 is the autocorrelation function of the first hydrophone;

[0051] Figure 5 is the autocorrelation function of the second hydrophone;

[0052] Figure 6 It is the error curve graph in the iterative process of solving the system of equations;

[0053] Figure 7 It is a graph of the calculation results during the iterative process of solving the system of equations;

[0054] Figure 8 It is the moving target ranging result diagram. DETAILED DESCRIPTION

[0055] Specific implementation method 1: Combination Figure 1 The present embodiment describes a method for passive ranging of a surface target based on vertical dual hydrophones, and the method specifically comprises the following steps:

[0056] Step 1: performing autocorrelation operation on the received signals of the two hydrophones respectively to obtain the autocorrelation functions of the two hydrophones, and the line connecting the two hydrophones is perpendicular to the water surface;

[0057] Step 2: extract the seabed reflection delay τ1 (i.e., the time delay difference between the target radiation noise signal reaching the corresponding hydrophone through direct transmission and seabed reflection) according to the autocorrelation function of the first hydrophone, and extract the seabed reflection delay τ2 according to the autocorrelation function of the second hydrophone;

[0058] Step 3: Based on the virtual source method and according to the seabed reflection delay τ1 and the seabed reflection delay τ2, a set of equations for calculating the horizontal distance between the hydrophone and the surface target at time t is established;

[0059] Step 4: Solve the equations established in step 3 to obtain the horizontal distance between the surface target and the hydrophone;

[0060] Step 5: Execute steps 1 to 4 for the signal received by the hydrophone at each moment to obtain the distance course measurement result for the surface target.

[0061] In practical applications, the initial value of the iteration at the current moment can be selected as the iteration result at the previous moment to increase the iteration speed. Figure 8 The estimation results at different distances are given, and it can be seen that they are basically consistent with the actual horizontal distance.

[0062] Specific implementation method 2: This implementation method is different from the specific implementation method 1 in that the autocorrelation operation is performed on the received signals of the two hydrophones respectively, specifically:

[0063] The signal g1(t) received by the first hydrophone at time t is expressed as:

[0064]

[0065] Where h1(t) represents the impulse response function of the first hydrophone channel at time t, represents convolution, s(t) represents the signal emitted by the target at time t, and n1(t) represents the noise signal received by the first hydrophone at time t;

[0066] The signal g2(t) received by the second hydrophone at time t is expressed as:

[0067]

[0068] Where h2(t) represents the impulse response function of the second hydrophone channel at time t, represents convolution, n2(t) represents the noise signal received by the second hydrophone at time t;

[0069] Assuming that the noises received by the two hydrophones are uncorrelated, after the signals are bandpass filtered, the autocorrelation functions of the first and second hydrophones at time t are expressed as:

[0070] R1(τ)=E[g1(t)g1(t-τ)]

[0071] R2(τ)=E[g2(t)g2(t-τ)]

[0072] Where R1(τ) represents the autocorrelation function of the first hydrophone, R2(τ) represents the autocorrelation function of the second hydrophone, and E[·] represents the expectation.

[0073] The other steps and parameters are the same as those in the first embodiment.

[0074] Using the fact that the seabed reflection coefficient is positive, the seabed reflected sound is consistent with the direct sound in phase, and the peak value in the autocorrelation function is positive, the autocorrelation function under different delays is plotted, and the peak position is the seabed reflection delay calculated at that moment. From the properties of the autocorrelation function, we can know that the time delay corresponding to the place with the largest peak in the autocorrelation function is 0. Except for the place with the largest peak, the time delay corresponds to the maximum peak in other places. Therefore, according to the principle of the autocorrelation function, the seabed reflection delay τ1 is determined according to the autocorrelation function of the first hydrophone, and the seabed reflection delay τ2 is determined according to the autocorrelation function of the second hydrophone. The seabed reflection delay is the arrival delay difference between the direct wave and the seabed reflection wave.

[0075] Specific implementation method three: This implementation method is different from specific implementation method one or two in that the impulse response function h1(t) of the first hydrophone channel at time t is:

[0076]

[0077] Where N is the number of eigenvalues ​​reaching the hydrophone, a i represents the amplitude of the i-th eigenvalue, τ 1,i represents the time delay of the i-th eigenwave reaching the first hydrophone, i = 0 represents the direct wave, and δ(t) is the unit impulse response;

[0078] The impulse response function h2(t) of the second hydrophone channel at time t is:

[0079]

[0080] Among them, τ 2,i represents the time delay of the i-th eigenvalue ray reaching the second hydrophone.

[0081] The other steps and parameters are the same as those in the first or second embodiment.

[0082] like Figure 2As shown, the top view of the target motion model is given as follows: the y-axis is due north, the x-axis is due east, the target moves straight toward the north at a uniform speed, the red curve is the target motion trajectory, and the blue circle is the position of the hydrophone.

[0083] Figure 3 A schematic diagram of the sound lines of the direct wave and the seabed reflection wave is given. It can be seen that the sound path of the target radiated noise signal reaching the hydrophone through direct and seabed reflection can be expressed as:

[0084]

[0085] Where r represents the horizontal distance between the hydrophone and the sound source, H represents the equivalent reflection depth of the seabed, H1 represents the depth of the first hydrophone, d1 represents the depth difference between the two hydrophones, and h represents the distance between the sound source and the sea surface. The time delay between the direct sound received by the first hydrophone and the reflected sound from the seabed is expressed as τ1 = (R 1BR -R 1D ) / c, the time delay between the direct sound received by the second hydrophone and the reflected sound from the seabed is expressed as τ2 = (R 2BR -R 2D ) / c, c is the equivalent speed of sound.

[0086] Figure 4 and Figure 5 The autocorrelation functions of the first and second hydrophones receiving 10-100 Hz broadband signals in the deep sea environment are given respectively. The red dotted lines in the figure are the extracted seabed reflection delays of different hydrophones, which increase with decreasing distance. At the same time, the seabed reflection delay of the first hydrophone is greater than that of the second hydrophone.

[0087] According to the above relationship, the following set of equations can be established.

[0088] Specific implementation method 4: This implementation method is different from any one of specific implementation methods 1 to 3 in that the equation group for calculating the horizontal distance between the hydrophone and the surface target at time t is established according to the seabed reflection delay τ1 and the seabed reflection delay τ2, specifically:

[0089] After obtaining the seabed reflection delay received by different hydrophones, the following set of equations can be established based on simple geometric relationships:

[0090]

[0091] Wherein, H is the equivalent reflection depth of the seabed (also called effective depth. Since low-frequency sound waves have strong penetrability and there is a sediment layer of a certain thickness on the seabed, they often penetrate into the sediment layer. Therefore, the actual reflection point depth is not necessarily the seawater depth. Moreover, due to the coupling between the thickness of the sediment layer and the sound velocity, it cannot be accurately estimated. In order to simplify the model, the concept of effective depth is introduced to compensate for the propagation of sound waves in the sediment layer), r is the horizontal distance between the surface target and the hydrophone (since the two hydrophones are arranged vertically, in the present invention, the horizontal distances between the target and the two hydrophones are equal), H1 is the depth of the first hydrophone, H2 is the depth of the second hydrophone, h is the depth of the noise signal source radiated by the surface target, c is the equivalent sound velocity in water, τ1 is the seabed reflection delay of the first hydrophone, and τ2 is the seabed reflection delay of the second hydrophone.

[0092] The other steps and parameters are the same as those in Specific Embodiments 1 to 3.

[0093] The first term on the right side of each equation represents the distance traveled by the seabed reflected sound line, the second term represents the distance traveled by the direct sound line, and the third term represents the product of the sound speed and the seabed reflection delay (that is, the distance traveled by the seabed reflected sound line more than the direct sound line). By solving the equation group, the horizontal distance and equivalent reflection depth can be obtained. The solved horizontal distance and equivalent reflection depth satisfy that F1(r,H) and F2(r,H) are both equal to 0.

[0094] Moreover, due to the complex sedimentary layers on the deep seabed, when the sound wave is reflected on the seabed, the actual seabed reflection point is not necessarily the sea depth (the depth from the sea surface to the seabed). If the sea depth is calculated as the actual seabed reflection point, there will be a large ranging error. Therefore, the present invention vertically arranges two hydrophones and introduces an equivalent reflection depth. Based on the equivalent reflection depth, the target horizontal distance and the equivalent reflection depth are solved, which improves the accuracy of the horizontal distance solution and solves the problem that the distance measurement will cause a large error when the sea depth is used as the seabed reflection point.

[0095] Specific implementation method five: This implementation method is different from any one of specific implementation methods one to four in that, in step four, the multivariate Newton iteration method is used to solve the equation group established in step three.

[0096] The other steps and parameters are the same as those in Specific Embodiments 1 to 4.

[0097] Specific implementation method 6: This implementation method is different from the specific implementation methods 1 to 5 in that the specific process of step 4 is as follows:

[0098] Step 41: Initialize the number of iterations k = 1 and initialize X 0 =[r0,H0] T, H0 represents the initialization value of the equivalent reflection depth of the seabed (which can be selected as the actual ocean depth, that is, the depth from the sea surface to the surface of the sediment layer), r0 represents the initialization value of the horizontal distance between the hydrophone and the surface target;

[0099] Step 42: According to X k Calculate X k+1 =[r k+1 ,H k+1 ] T :

[0100]

[0101] Where G is the Jacobian matrix, Represents the iteration increment;

[0102] Step 43: Determine whether the iteration increment satisfies Among them, ε is the set threshold (the specific value can be set according to the actual situation), ‖·‖2 means calculating the 2-norm;

[0103] If satisfied, then H k+1 As an estimate of the depth of the seafloor reflection point, r k+1 As an estimate of the horizontal distance between the surface target and the hydrophone;

[0104] If not satisfied, set k=k+1 and return to step 42.

[0105] The other steps and parameters are the same as those in Specific Implementation Methods 1 to 5.

[0106] The system of equations established in step 3 is a nonlinear system of equations. After the initial value is given, the iteration is continued until the iteration termination condition is reached. The invention sets the iteration termination condition as the 2-norm value of the iteration increment is less than 10 -3 . Figure 6 and Figure 7 The iterative process at the first moment is given. At this moment, the horizontal distance between the hydrophone and the surface target is 7238.48 meters. The initial value is selected as X=[5000; 4360]. It can be seen that with the progress of the iteration process, the errors of the two equations move in the direction of negative gradient, the error gradually approaches zero, and the initial value also gradually approaches the true value. The estimated result obtained by the final iteration is 7729.89 meters, which is close to the true value. Due to the obvious sound line bending phenomenon in the deep sea, there is a theoretical error in the virtual source model, but in general the error is acceptable.

[0107] Specific implementation method 7: This implementation method is different from any one of specific implementation methods 1 to 6 in that the Jacobian matrix G is:

[0108]

[0109] The other steps and parameters are the same as those in Specific Embodiments 1 to 6.

[0110] Specific implementation example eight: A computer storage medium of this implementation example stores at least one instruction, and the at least one instruction is loaded and executed by a processor to implement the passive ranging method for surface targets based on vertical dual hydrophones.

[0111] It should be understood that the instructions include computer program products, software or computerized methods corresponding to any method described in the present invention; the instructions can be used to program a computer system, or other electronic device. Computer storage media may include readable media on which instructions are stored, which may include but are not limited to magnetic storage media, optical storage media; magneto-optical storage media include read-only memory, random access memory, erasable programmable memory such as, and and flash memory layers, or other types of media suitable for storing electronic instructions.

[0112] Specific embodiment 9: This embodiment is a passive ranging device for surface targets based on vertical dual hydrophones, the device includes a processor and a memory. It should be understood that including any device including a processor and a memory described in the present invention, the device may also include other units and modules that perform display, interaction, processing, control, etc. and other functions through signals or instructions;

[0113] At least one instruction is stored in the memory, and the at least one instruction is loaded and executed by the processor to implement the passive ranging method for surface targets based on vertical dual hydrophones.

[0114] The above calculation examples of the present invention are only used to explain the calculation model and calculation process of the present invention in detail, and are not intended to limit the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A passive ranging method for surface targets based on vertical dual hydrophones, characterized in that: The method specifically comprises the following steps: Step 1: performing autocorrelation operation on the received signals of the two hydrophones respectively to obtain the autocorrelation functions of the two hydrophones, and the line connecting the two hydrophones is perpendicular to the water surface; Step 2: extracting the seabed reflection delay τ1 according to the autocorrelation function of the first hydrophone, and extracting the seabed reflection delay τ2 according to the autocorrelation function of the second hydrophone; Step 3: Establish a set of equations for calculating the horizontal distance between the hydrophone and the surface target at time t according to the seabed reflection delay τ1 and the seabed reflection delay τ2; Step 4: Solve the equations established in step 3 to obtain the horizontal distance between the surface target and the hydrophone; Step 5: Execute steps 1 to 4 for the signal received by the hydrophone at each moment to obtain the distance course measurement result for the surface target.

2. The method for passive ranging of surface targets based on vertical dual hydrophones according to claim 1, characterized in that: The autocorrelation operation is performed on the received signals of the two hydrophones respectively, specifically: The signal g1(t) received by the first hydrophone at time t is expressed as: Where h1(t) represents the impulse response function of the first hydrophone channel at time t, represents convolution, s(t) represents the signal emitted by the target at time t, and n1(t) represents the noise signal received by the first hydrophone at time t; The signal g2(t) received by the second hydrophone at time t is expressed as: Where h2(t) represents the impulse response function of the second hydrophone channel at time t, represents convolution, n2(t) represents the noise signal received by the second hydrophone at time t; Then the autocorrelation functions of the first hydrophone and the second hydrophone at time t are expressed as: R1(τ)=E[g1(t)g1(t-τ)] R2(τ)=E[g2(t)g2(t-τ)] Where R1(τ) represents the autocorrelation function of the first hydrophone, R2(τ) represents the autocorrelation function of the second hydrophone, and E[·] represents the expectation.

3. The method for passive ranging of surface targets based on vertical dual hydrophones according to claim 2 is characterized in that: The impulse response function h1(t) of the first hydrophone channel at time t is: Where N is the number of eigenvalues ​​reaching the hydrophone, a i represents the amplitude of the i-th eigenvalue, τ 1,i represents the time delay of the i-th eigenwave reaching the first hydrophone, i = 0 represents the direct wave, and δ(t) is the unit impulse response; The impulse response function h2(t) of the second hydrophone channel at time t is: Among them, τ 2,i represents the time delay of the i-th eigenvalue ray reaching the second hydrophone.

4. The method for passive ranging of surface targets based on vertical dual hydrophones according to claim 3 is characterized in that: The equation group for calculating the horizontal distance between the hydrophone and the surface target at time t is established according to the seabed reflection delay τ1 and the seabed reflection delay τ2, specifically: Wherein, H is the equivalent reflection depth of the seabed, r is the horizontal distance between the surface target and the hydrophone, H1 is the depth of the first hydrophone, H2 is the depth of the second hydrophone, h is the source depth of the noise signal radiated by the surface target, c is the equivalent sound speed in water, τ1 is the seabed reflection delay of the first hydrophone, and τ2 is the seabed reflection delay of the second hydrophone.

5. The method for passive ranging of surface targets based on vertical dual hydrophones according to claim 4 is characterized in that: In the step 4, the multivariate Newton iteration method is used to solve the equation group established in the step 3.

6. The method for passive ranging of surface targets based on vertical dual hydrophones according to claim 5, characterized in that: The specific process of step 4 is as follows: Step 41: Initialize the number of iterations k = 1 and initialize X 0 =[r0,H0] T , H0 represents the initialization value of the equivalent reflection depth of the seabed, r0 represents the initialization value of the horizontal distance between the hydrophone and the surface target; Step 42: According to X k Calculate X k+1 =[r k+1 ,H k+1 ] T : Where G is the Jacobian matrix, Represents the iteration increment; Step 43: Determine whether the iteration increment satisfies Among them, ε is the set threshold, ||·||2 means calculating the 2-norm; If satisfied, then H k+1 As an estimate of the depth of the seafloor reflection point, r k+1 As an estimate of the horizontal distance between the surface target and the hydrophone; If not satisfied, set k=k+1 and return to step 42.

7. The method for passive ranging of surface targets based on vertical dual hydrophones according to claim 6 is characterized in that: The Jacobian matrix G is:

8. A computer storage medium, characterized in that The storage medium stores at least one instruction, and the at least one instruction is loaded and executed by the processor to implement the passive ranging method for surface targets based on vertical dual hydrophones as described in any one of claims 1 to 7.

9. A passive ranging device for surface targets based on vertical dual hydrophones, characterized in that: The device includes a processor and a memory, wherein the memory stores at least one instruction, and the at least one instruction is loaded and executed by the processor to implement a passive ranging method for surface targets based on vertical dual hydrophones as described in any one of claims 1 to 7.

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