Method and system for eliminating echo signals of target shielding area in D-MBES data acquisition simulator under sound velocity profile condition
By addressing the target occlusion problem in the D-MBES data acquisition simulator through virtual straightening of curved sound rays and convex hull occlusion algorithms, the simulation accuracy of echo signals under complex seabed topography is improved, and the problem of insufficient simulation accuracy under sound velocity profile conditions is solved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INST OF ACOUSTICS CHINESE ACAD OF SCI
- Filing Date
- 2025-12-30
- Publication Date
- 2026-05-19
AI Technical Summary
Under sound velocity profile conditions, the existing technology in the D-MBES data acquisition simulator fails to effectively handle the target obstruction problem caused by complex seabed topography, resulting in a decrease in the simulation accuracy of echo signals.
By employing the virtual straightening technique for curved sound rays and the convex hull blocking algorithm, the possible effective scattering units corresponding to the transmitted beam are calculated, the grazing angle and azimuth angle of the sound ray are calculated, geometric transformation and convex hull blocking processing are performed, and the effective scattering units in the blocked area are eliminated to obtain the true coordinates.
It improves the simulation accuracy of echo signals under sound velocity profile conditions, enhances the accuracy of multibeam sonar data simulation, and is suitable for complex seabed environments.
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Figure CN122063571A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the fields of marine acoustic seabed topography detection technology and deep-water multibeam bathymetry sonar data acquisition simulation, and particularly to a method and system for eliminating echo signals from target-obstructed areas under sound velocity profile conditions in a D-MBES data acquisition simulator. Background Technology
[0002] Deep-water multi-beam echo sounder (D-MBES) is one of the key technologies for modern marine surveying and seabed topography exploration. For deep-sea and complex seabed areas, high-precision and high-efficiency depth sounding data acquisition is particularly important. The purpose of a D-MBES data acquisition simulator is to simulate actual D-MBES operations using a digital simulation system. Its main function is to generate D-MBES test data that meets specific parameter requirements during the research, development, debugging, and maintenance of sonar equipment, thereby completing tasks such as performance testing and calibration of the sonar equipment. Different functional sonar technologies operate on different principles, leading to a high degree of specialization in sonar data acquisition simulators. Domestic D-MBES research started relatively late, and the testing of echo processing equipment during the development phase still relies on preset random data, hindering the horizontal and vertical development of D-MBES. To accelerate the research process in the domestic D-MBES field, research on dedicated data acquisition simulators is indispensable.
[0003] The construction method of underwater detection equipment data simulation mainly depends on the available computing power and the accuracy requirements for describing physical phenomena. Sonar data acquisition simulators have been studied since the 1980s. The design mechanism often ignores the sonar working environment and constructs echo signals based on problems. The ability to solve problems is obviously limited. In response to this problem, Zhang Wei et al. considered that the number of transmitting array elements of D-MBES is several times greater than that of shallow water MBES. They proposed the amplitude weighting (AW) simulation algorithm (reference [1] Zhang Wei, Liu Xiaodong, Liu Zhiyu, et al. Fast simulation method of seabed echo signal of deep water multibeam bathymetry system [J]. Acoustic Technology, 2015, 34(01):11-17). That is, the transmitting array elements are used to calculate the transmitting beam footprint, and then the transmitting array is equivalent to the transmitting point source to reduce the amount of calculation, thereby realizing the simulation of the echo signal of D-MBES single Ping. The above methods have certain feasibility and effectiveness when simulating echo data under unobstructed and gentle seabed topography conditions. However, this method does not adequately account for the obstruction caused by complex seabed topography such as protrusions or depressions, especially under sound velocity profile conditions. This deficiency leads to a significant decrease in simulation accuracy, limiting its accuracy in simulating echo signals under complex seabed topography. Summary of the Invention
[0004] The purpose of this application is to address the impact of target obstruction caused by complex seabed topography on the simulation accuracy of D-MBES echo data.
[0005] To achieve the above objectives, this invention provides a method for eliminating echo signals from target occlusion areas in a D-MBES data acquisition simulator under sound velocity profile conditions. Based on the convex hull occlusion algorithm, it proposes a virtual straightening technique for curved sound rays, effectively improving the simulation accuracy of echo signals under complex terrain conditions with sound velocity profiles. Specifically, the method includes the following steps: Step 1: Calculate the possible effective scattering elements corresponding to the transmitted beam; Step 2: In the track coordinate system, calculate the grazing angle and azimuth angle of the acoustic ray from each potentially effective scattering element within the transmitted beam to the viewpoint position; Step 3: Calculate the virtual coordinates of potentially effective scattering elements within the transmitted beam; Step 4: Perform geometric transformation on potentially effective scattering units: After transforming the viewpoint to the origin of the track coordinate system, perform geometric transformation on potentially effective scattering units; Step 5: Find the convex hull of the union of the potentially effective scattering cells and the origin of the track coordinate system, and remove the origin of the track coordinate system; Step 6: Calculate the virtual coordinates of the effective scattering cells after removing the possible effective scattering cells that may have been blocked; Step 7: Obtain the true coordinates of the effective scattering unit based on the index relationship between the virtual coordinates and the real coordinates of the scattering unit.
[0006] As an improvement to the above method, step 1 specifically includes: in the track coordinate system, using beamforming and three-dimensional beam stabilization techniques to calculate the amplitude of each seabed scattering unit, normalizing it with the maximum amplitude value, and calculating its decibel value; seabed scattering units with decibel values higher than a set threshold are potentially effective scattering units corresponding to the transmitted beam.
[0007] As another improvement to the above method, step 2 specifically includes: Consider the first ping, the strip, first The first wave within the transmission beam Coordinates of one possible effective scattering unit , , This indicates the total number of potentially effective scattering elements of the transmitted beam, and the viewpoint coordinates. The grazing angle of the acoustic rays from the effective scattering element of the transmitted beam to the viewpoint position is calculated using equations (1) and (2). and azimuth ; glancing angle The solution is obtained by iteratively solving the problem based on the three-dimensional coordinates of the viewpoint, the three-dimensional coordinates of the effective scattering unit, and equation (1). (1) in, Indicates the first in the water body Horizontal displacement of the layer; Indicates the first in the water body Propagation time of layers; The velocity of sound at the location of the sound source; Indicates the first in the water body The sound velocity gradient of the layer; Indicates water depth The speed of sound at that location; Indicates the vocal range The angle of attack at that location; Azimuth The calculation expression is: (2) in, Represents the three-dimensional coordinates of the viewpoint in the track coordinate system; the origin of the track coordinate system is the inertial navigation measurement center; the X-axis is the track direction parallel to the carrier reference plane; the Y-axis is the direction perpendicular to the left side of the track parallel to the carrier reference plane; and the Z-axis is the direction perpendicular to the carrier reference plane and upwards.
[0008] As a further improvement to the above method, step 3 specifically includes: calculating the virtual coordinates of the potentially effective scattering elements within the transmitted beam using equations (3) and (4), with the specific calculation formulas being: (3) (4) in, This represents the virtual coordinates of the potentially effective scattering unit in the track coordinate system.
[0009] As an improvement to the above method, the formula for the geometric transformation in step 4 is: (5) in, ; Indicates the mirror radius, and .
[0010] As a further improvement to the above method, step 5 specifically includes: finding potentially effective scattering elements within the transmitted beam. and the origin of the track coordinate system The convex hull of the union, with the origin removed. ,Right now: (6) in, It is the convex hull operator; It is the set union operator; It is the set difference operator.
[0011] As a further improvement to the above method, step 6 specifically includes: by... Performing an inverse transform yields the visible point from the viewpoint, thereby obtaining the effective scattering unit after removing obstructions from the transmitted beam. The inverse transform is expressed as: (7) in, express The inverse operation.
[0012] As a further improvement to the above method, the method also includes the step of calculating the seabed echo signal using the true coordinates of the effective scattering unit.
[0013] To achieve the above objectives, the present invention also provides a target occlusion region echo signal elimination system under the condition of sound velocity profile in a D-MBES data acquisition simulator. The system is characterized in that it includes: a D-MBES data acquisition simulator, a processor, and a storage medium storing a computer program, wherein the processor loads the computer program to implement the steps of the above-mentioned target occlusion region echo signal elimination method to obtain the true coordinates of the effective scattering unit.
[0014] To achieve the above objectives, the present invention also provides a computer-readable storage medium, characterized in that it includes a computer program stored thereon, the computer program being executable by a processor to implement the steps of the above-described method for eliminating echo signals from the target occlusion region.
[0015] Compared with the prior art, the significant technical advantages of the present invention are as follows: This invention organically integrates virtual straightening technology for curved sound rays and convex hull hidden point removal algorithm into the D-MBES echo data simulation process, effectively solving the problem of echo signal removal in the target obstruction area under sound velocity profile conditions, improving the accuracy of echo signal simulation, and providing an effective solution for multibeam sonar data simulation and related research in complex seabed environments. Attached Figure Description
[0016] Figure 1 This is a flowchart of a method for removing echo signals from target occlusion areas under the condition of sound speed profile in a D-MBES data acquisition simulator with specific implementation details. Figure 2 This is a schematic diagram of the occlusion model in a specific implementation method; Figure 3This is a schematic diagram illustrating the principle of virtual straightening of curved sound lines in a specific implementation method; Figure 4a In specific implementations, this represents the difference between virtual and real coordinates under positive gradient sound velocity profile conditions; Figure 4b In specific implementations, this represents the difference between virtual and real coordinates under negative gradient sound velocity profile conditions; Figure 4c The difference between the blocked area under the positive gradient sound speed profile condition and the blocked area under the constant sound speed condition is reflected in the specific implementation. Figure 4d The difference between the obstructed area under negative gradient sound speed profile conditions and the obstructed area under constant sound speed conditions is reflected in the specific implementation. Figure 5a In a specific implementation, the water body image is generated after signal processing of data simulated using the AW algorithm. Figure 5b In a specific embodiment, the method of the present invention is used to simulate water images after signal processing of data; Figure 6a This is a side-scan imaging image obtained by simulating data using the AW algorithm and processing it in a specific implementation method. Figure 6b This is a side-scan imaging image of simulated data processed by the method of the present invention in a specific embodiment; Figure 7a In specific implementation methods Figure 5a and Figure 5b The seabed topographic map used; Figure 7b In specific implementation methods Figure 6a and Figure 6b The seabed topographic map used. Detailed Implementation
[0017] To achieve the above-mentioned objectives, this invention provides a method for eliminating echo signals from target occlusion areas in a D-MBES data acquisition simulator under sound speed profile conditions. Based on the convex hull occlusion algorithm, it proposes a virtual straightening technique for curved sound lines, which effectively improves the simulation accuracy of echo signals under complex terrain conditions with sound speed profiles.
[0018] The technical solution of this invention proposes a target obstruction method under sound velocity profile conditions, which is used for high-precision simulation of multibeam bathymetry data under complex seabed topography with obstruction. The method mainly includes: ① calculating the grazing angle and azimuth angle of the acoustic rays from the viewpoint (center of the transmitting array) of the potentially effective scattering unit; ② calculating the virtual coordinates of the potentially effective scattering unit; ③ using the convex hull obstruction algorithm to remove the potentially effective scattering units obstructed by the target, thereby obtaining the effective scattering units under the virtual coordinates; ④ then obtaining the real coordinates of the effective scattering units according to the index relationship between the virtual coordinates and the real coordinates of the scattering units.
[0019] The following is a detailed description of the method for eliminating echo signals from target occlusion areas in the D-MBES data acquisition simulator under the condition of sound speed profile, proposed in this invention, with reference to the accompanying drawings. Figure 1 A flowchart of the method of the present invention is provided. The method of this specific embodiment includes the following steps: Step 1: Calculate the possible effective scattering elements corresponding to the transmitted beam; in the track coordinate system, use beamforming and three-dimensional beam stabilization techniques to calculate the amplitude of each seabed scattering element, and use the maximum amplitude. Normalize it and calculate its decibel value, i.e. , Indicates the first The amplitude of each seabed scattering element is set. A threshold value is set (the threshold value is generally greater than the decibel value corresponding to the half-power beamwidth of the beamforming, i.e., -3dB. In this embodiment, it is set to -3dB). Seabed scattering elements with amplitudes higher than the threshold value are the possible effective scattering elements corresponding to the transmitted beam.
[0020] Step 2: In the track coordinate system, calculate the grazing angle and azimuth angle of the acoustic ray from each potentially effective scattering element within the transmitted beam to the viewpoint position (center of the transmitted array); like Figure 2 As shown in the occlusion model, target occlusion is commonly seen in complex terrains such as seabed protrusions or depressions. Consider the coordinates of a potentially effective scattering unit. (No. ping, the strip, first The first wave within the transmission beam One potentially effective scattering unit, , (This indicates the total number of potentially effective scattering elements of the transmitted beam), viewpoint coordinates. The grazing angle of the acoustic rays from the effective scattering element of the transmitted beam to the viewpoint position is calculated using equations (1) and (2). and azimuth Grazing angle It is necessary to solve the problem iteratively based on the three-dimensional coordinates of the viewpoint, the three-dimensional coordinates of the effective scattering unit, and equation (1).
[0021] (1) in, Indicates the first in the water body Horizontal displacement of the layer; Indicates the first in the water body Propagation time of layers; The velocity of sound at the location of the sound source; Indicates the first in the water body The sound velocity gradient of the layer; Indicates water depth The speed of sound at that location; Indicates the vocal range The glancing angle at that location.
[0022] Azimuth The calculation expression is: (2) in, Represents the three-dimensional coordinates of the viewpoint in the track coordinate system; the origin of the track coordinate system is the inertial navigation measurement center; the X-axis is the track direction parallel to the carrier reference plane; the Y-axis is the direction perpendicular to the left side of the track parallel to the carrier reference plane; and the Z-axis is the direction perpendicular to the carrier reference plane and upwards.
[0023] Step 3: Calculate the virtual coordinates of potentially effective scattering elements within the transmitted beam; The virtual coordinates of the potentially effective scattering elements within the transmitted beam are calculated using equations (3) and (4). The specific calculation formula is as follows: (3) (4) in, This represents the virtual coordinates of the potentially effective scattering unit in the track coordinate system. Formulas (1), (2), (3), and (4) are the steps for virtual straightening of curved sound rays. Figure 3 The diagram illustrates the principle of virtual straightening of curved sound rays. Target 1 and Target 2 are transformed into virtual coordinates Target 1' and Target 2' through the virtual straightening process of curved sound rays. Figure 4a and Figure 4b As shown, Figure 4a This represents the difference between virtual and real coordinates under a positive gradient sound velocity profile. Figure 4b This represents the difference between virtual and real coordinates under negative gradient sound velocity profile conditions. Figure 4a and Figure 4b The results clearly conform to the physical laws of sound wave propagation. After... Figure 4a and Figure 4bThe transformation process unifies the originally changing sound velocity profile conditions into a constant sound velocity state in the virtual coordinates. In this state, the sound rays will propagate in a straight line, so the convex hull occlusion algorithm can be used for hidden point detection, i.e., formulas (5), (6), and (7).
[0024] Step 4: Perform geometric transformations on potentially effective scattering units; After transforming the viewpoint to the origin, a geometric transformation is performed on the potentially effective scattering units. The transformation formula is expressed as follows: (5) in, ; Indicates the mirror radius, and .
[0025] Step 5: Find the convex hull of the union of the potentially effective scattering units and the origin, and remove the origin; Find potentially effective scattering elements within the transmitted beam. and the origin of the track coordinate system The convex hull of the union, with the origin removed. ,Right now: (6) in, It is the convex hull operator; It is the set union operator; It is the set difference operator.
[0026] Step 6: Calculate the virtual coordinates of the effective scattering cells after removing the possible effective scattering cells that may have been blocked; Through the By performing an inverse transform, the visible point at this viewpoint can be obtained, and from this, the effective scattering unit after removing the obstruction of the transmitted beam can be obtained. The inverse transform is expressed as: (7) in, express The inverse operation.
[0027] Step 7: Obtain the true coordinates of the effective scattering unit based on the index relationship between the virtual coordinates and the real coordinates of the scattering unit.
[0028] The principle of the relationship between virtual coordinates and real coordinates scattering unit indices is that for matrices of the same dimension, virtual coordinates A and real coordinates B, if some rows in virtual coordinates A are effective scattering unit virtual coordinates, then the corresponding rows in B are effective scattering unit real coordinates.
[0029] Finally, the seabed echo signal is calculated using the true coordinates of the effective scattering units.
[0030] For other transmitted beams, perform the same calculations as described above.
[0031] Figure 4a , Figure 4b , Figure 4c and Figure 4d The target obstruction effect under constant sound speed and sound speed profile conditions on the same seabed is presented. The depth range of the sound speed profile covers 0–600 m, and the sound speed range is 1420–1580 m / s. According to the physical laws of sound wave propagation, under a positive gradient sound speed profile, the sound ray bends towards the sea surface. When the coordinates of the seabed scattering units are mapped to the coordinates of the virtual scattering units by virtually straightening the bent sound ray, the planar coordinates exhibit a cohesive effect; while under a negative gradient sound speed profile, the sound ray bends towards the seabed, and the planar coordinates of the virtual scattering units exhibit a diffusion effect. Figure 4a This represents the difference between virtual and real coordinates under a positive gradient sound velocity profile. Figure 4b This represents the difference between virtual and real coordinates under negative gradient sound velocity profile conditions. Figure 4a and Figure 4b The results clearly conform to the physical laws of sound wave propagation. After... Figure 4a and Figure 4b Through transformation, the originally varying sound velocity profile is unified into a constant sound velocity state in the virtual coordinates. In this state, sound rays will propagate in a straight line, so the convex hull occlusion algorithm can be used for hidden point detection. Figure 4c This represents the difference between the blocked region under positive gradient sound speed profile conditions and the blocked region under constant sound speed conditions. Figure 4d The diagram illustrates the difference in the obstructed region between the negative gradient sound speed profile and the constant sound speed profile; the obstructed region is represented by the white area in the figure. Under this condition, due to the curvature of sound rays towards the sea surface, the horizontal distance required for sound rays with the same emission grazing angle to reach the same depth scattering unit increases, resulting in a larger obstructed region compared to the constant sound speed case. Furthermore... Figure 4d Under negative gradient profile conditions, sound rays bend towards the seabed, and the horizontal distance for sound rays with the same emission glancing angle to reach the same depth scattering unit is shortened, resulting in a corresponding reduction in the blocked area compared to the case of constant sound speed. Figure Figure 4c and Figure 4d The results also align with physical laws.
[0032] Comparison of system simulation accuracy of the method of this invention: The method of this invention was applied to the D-MBES data acquisition simulator, generating 50 ping single-ping data points for the experimental seabed area (a). The experimental seabed (a) is shown below. Figure 7aThe image shows the seabed data from a single ping, with colors representing different water depths. Ridges and trenches were constructed on the -500m seabed. The ridge peaks were at a depth of -300m and 300m from the center of the transmitting array in the vertical direction of the flight path. The lowest point of the trenches was at a depth of -700m and 600m from the center of the transmitting array in the vertical direction of the flight path. The undulating terrain caused acoustic obstruction of some scattering elements by the ridges and trenches. After signal processing by the V-shaped Deep Water Multibeam Echo Sounder (VD-MBES), the water body and depth measurement results are shown in Figure 5, comparing the water imaging and depth measurement results. Figure 5a This represents a water body image after signal processing of data simulated by the AW algorithm. Figure 5b This represents a water image generated after signal processing of the simulated data by the method of this invention. Comparing it with manually labeled occluded areas, it is evident that the AW algorithm results in false terrain in the water image. Figure 5a The fake terrain is within the area bounded by the white box, while the actual terrain is... Figure 5b (As shown by the black line within the white box in the image). The method of this invention effectively eliminates the interference of hidden scattering units on the echo signal, making the seabed topography in the water image more realistic. Experimental results verify that the method of this invention effectively improves the simulation accuracy of echo data from the D-MBES data acquisition simulator.
[0033] Figure 6a and Figure 6b Side-scan imaging comparisons demonstrate the 74-ping survey line data generated using the D-MBES data acquisition simulator in the experimental seabed area (b). Experimental seabed (b) is shown below. Figure 7b As shown, colors represent different water depths. A hemisphere with a radius of 200m (target 1), a truncated pyramid with a lower base side length of 500m, an upper base side length of 400m, and a height of 50m (target 2), and a frustum with a lower base radius of 250m, an upper base radius of 200m, and a height of 50m (target 3) were constructed on the seabed at a depth of -1500m. It is known that the hemisphere obstructs some of the seabed scattering elements below it, while the truncated pyramid and frustum are fully visible and do not obstruct the view. Pink boxes indicate the starting point of the survey line, red triangles indicate the ending point, and black lines represent the survey line itself. After processing by the VD-MBES signal processing unit, the side-scan image is as follows: Figure 6a and Figure 6b The side-scan imaging comparison is shown. Among them, Figure 6a Using the AW algorithm, Figure 6bThe method of this invention is employed. A comparison reveals that, in the obscured area, the side-scan sonar image generated by the method of this invention exhibits a significant shadow area consistent with physical laws, namely the small green arc-shaped area to the left of target 1; while the image generated by the AW algorithm in the same area produces false target echo signals, leading to abnormal imaging. This phenomenon also verifies that the method of this invention is significantly superior to the AW algorithm in simulation accuracy, expanding the application scope of the D-MBES data acquisition simulator. Although the method of this invention is proposed in the context of D-MBES, it is also applicable to detection-type sonar such as shallow water multibeam bathymetry sonar, bathymetry side-scan sonar, and synthetic aperture sonar.
[0034] A specific embodiment of the present invention also provides a target obstruction area echo signal removal system under sound speed profile conditions in a D-MBES data acquisition simulator. This system includes: a D-MBES data acquisition simulator, a processor, and a storage medium storing an executable computer program. The processor loads the executable program to implement the aforementioned target obstruction area echo signal removal method under sound speed profile conditions in the D-MBES data acquisition simulator, obtaining the true coordinates of the effective scattering units. The processor can also be used to calculate seabed echo signals using the true coordinates of the effective scattering units.
[0035] A specific embodiment of the present invention also provides a computer-readable storage medium, including a computer program stored thereon, the computer program being executable by a processor to implement the steps of the target occlusion region echo signal removal method described above.
[0036] 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 method for eliminating echo signals from target obstruction areas in a D-MBES data acquisition simulator under conditions of sound velocity profiles, characterized in that, Includes the following steps: Step 1: Calculate the possible effective scattering elements corresponding to the transmitted beam; Step 2: In the track coordinate system, calculate the grazing angle and azimuth angle of the acoustic ray from each potentially effective scattering element within the transmitted beam to the viewpoint position; Step 3: Calculate the virtual coordinates of potentially effective scattering elements within the transmitted beam; Step 4: Perform geometric transformation on potentially effective scattering units: After transforming the viewpoint to the origin of the track coordinate system, perform geometric transformation on potentially effective scattering units; Step 5: Find the convex hull of the union of the potentially effective scattering cells and the origin of the track coordinate system, and remove the origin of the track coordinate system; Step 6: Calculate the virtual coordinates of the effective scattering cells after removing the possible effective scattering cells that may have been blocked; Step 7: Obtain the true coordinates of the effective scattering unit based on the index relationship between the virtual coordinates and the real coordinates of the scattering unit.
2. The method for eliminating echo signals in a target occlusion area according to claim 1, characterized in that, Step 1 specifically includes: in the track coordinate system, using beamforming and three-dimensional beam stabilization techniques to calculate the amplitude of each seabed scattering unit, normalizing it with the maximum amplitude value, and calculating its decibel value; seabed scattering units with decibel values higher than a set threshold are the possible effective scattering units corresponding to the transmitted beam.
3. The method for eliminating echo signals in a target occlusion area according to claim 1, characterized in that, Step 2 specifically includes: Consider the first ping, the strip, first The first wave within the transmission beam Coordinates of one possible effective scattering unit , , This indicates the total number of potentially effective scattering elements of the transmitted beam, and the viewpoint coordinates. The grazing angle of the acoustic rays from the effective scattering element of the transmitted beam to the viewpoint position is calculated using equations (1) and (2). and azimuth ; glancing angle The solution is obtained by iteratively solving the problem based on the three-dimensional coordinates of the viewpoint, the three-dimensional coordinates of the effective scattering unit, and equation (1). ； (1) in, Indicates the first in the water body Horizontal displacement of the layer; Indicates the first in the water body Propagation time of layers; The velocity of sound at the location of the sound source; Indicates the first in the water body The sound velocity gradient of the layer; Indicates water depth The speed of sound at that location; Indicates the vocal range The angle of attack at that location; Azimuth The calculation expression is: ； (2) in, Represents the three-dimensional coordinates of the viewpoint in the track coordinate system; the origin of the track coordinate system is the inertial navigation measurement center; the X-axis is the track direction parallel to the carrier reference plane; the Y-axis is the direction perpendicular to the left side of the track parallel to the carrier reference plane; and the Z-axis is the direction perpendicular to the carrier reference plane and upwards.
4. The method for eliminating echo signals in a target occlusion area according to claim 1, characterized in that, Step 3 specifically includes: calculating the virtual coordinates of the potentially effective scattering elements within the transmitted beam using equations (3) and (4). The calculation formula is as follows: ； (3) ； (4) in, This represents the virtual coordinates of the potentially effective scattering unit in the track coordinate system.
5. The method for eliminating echo signals in a target occlusion area according to claim 1, characterized in that, The geometric transformation formula mentioned in step 4 is: ； (5) in, ; Indicates the mirror radius, and .
6. The method for eliminating echo signals in a target occlusion area according to claim 1, characterized in that, Step 5 specifically includes: finding potentially effective scattering elements within the transmitted beam. and the origin of the track coordinate system The convex hull of the union, with the origin removed. ,Right now: ； (6) in, It is the convex hull operator; It is the set union operator; It is the set difference operator.
7. The method for eliminating echo signals in a target occlusion area according to claim 6, characterized in that, Step 6 specifically includes: through the... Performing an inverse transform yields the visible point from the viewpoint, thereby obtaining the effective scattering unit after removing obstructions from the transmitted beam. The inverse transform is expressed as: ； (7) in, express The inverse operation.
8. The method for eliminating echo signals in a target occlusion area according to claim 1, characterized in that, It also includes the step of calculating the seabed echo signal using the true coordinates of the effective scattering unit.
9. A system for eliminating echo signals from target obstruction areas in a D-MBES data acquisition simulator under conditions of sound velocity profiles, characterized in that, The system includes: a D-MBES data acquisition simulator, a processor, and a storage medium storing a computer program, wherein the processor loads the computer program to implement the steps of the target occlusion region echo signal elimination method according to any one of claims 1-7, and obtains the true coordinates of the effective scattering unit.
10. A computer-readable storage medium, characterized in that, Includes a computer program stored thereon, which can be executed by a processor to implement the steps of the target occlusion region echo signal removal method according to any one of claims 1-7.