A Simulation and Evaluation Method for the Characteristics of Transmitting-Receiving Co-located Time-domain Echo Broadening of an Underwater Vehicle

Abstract

The present invention provides a method for evaluating the time-domain echo broadening characteristics of a transceiver co-located underwater vehicle, including determining the geometric model parameters of the underwater vehicle, determining the time-domain acoustic wave information under full-angle incidence and converting it into a frequency-domain signal, determining the coordinates of the incident point and the receiving point, evaluating the reflection coefficient and transmission coefficient of the underwater vehicle's outer shell at different frequencies under full angle, establishing a model according to the shell form of the underwater vehicle to calculate the full-angle target frequency-domain transfer function; processing the full-angle target frequency-domain transfer function and the incident frequency-domain signal to obtain the time-domain echo broadening characteristics of the transceiver co-located underwater vehicle, and comparing the index requirements to obtain an evaluation conclusion. The present invention takes the geometric model of the underwater vehicle, material parameters, and the incident signal under full angle as inputs, and realizes the evaluation of the time-domain echo broadening characteristics index of the transceiver co-located underwater vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater vehicle acoustic stealth demonstration and evaluation, and particularly relates to a method for evaluating the characteristics of time-domain echo broadening of a combined transceiver for an underwater vehicle. Background Art

[0002] At present, there is no analysis method based on quantitative calculation or simulation for evaluating the characteristics of time-domain echo broadening of a combined transceiver for an underwater vehicle at home and abroad. In the overall design stage of an underwater vehicle, the overall design results of the underwater vehicle include documents and drawings such as the overall design specification, basic structure design specification, body line drawing, basic structure drawing, general arrangement drawing, and appendage structure drawing. The form, size, shell thickness and other parameter information of the inner and outer shell structures, base structures and inter-side structures of the underwater vehicle related to the overall design of the underwater vehicle have been initially determined. Therefore, an evaluation of the characteristics of time-domain echo broadening of the combined transceiver of the overall design of the underwater vehicle is established with these parameters and the incident signal as inputs, so as to realize a quantitative risk assessment of the time-domain echo broadening characteristic index of the overall design of the underwater vehicle, which has important practical application value for the acoustic stealth technology of the underwater vehicle. Summary of the Invention

[0003] Object of the Invention: In the overall design stage, according to the overall design scheme of the underwater vehicle, using the Kirchhoff approximation, with the full-angle combined transceiver target characteristic data and the incident signal as inputs, the characteristics of time-domain echo broadening are evaluated and compared with the index requirements to realize the risk assessment of the reachability of the time-domain echo broadening characteristic index of the overall design.

[0004] Technical Solution: A simulation evaluation method for the characteristics of time-domain echo broadening of a combined transceiver for an underwater vehicle, comprising the following steps:

[0005] Step 1. Analyze the overall design results of the underwater vehicle and sort out the structural modeling parameters to establish a geometric simulation model;

[0006] Analyze the overall design results of the underwater vehicle, including documents and drawings such as the overall design specification, basic structure design specification, body line drawing, basic structure drawing, general arrangement drawing, etc., and the form, size, shell thickness and other parameters of the inner and outer shell structures of the underwater vehicle related to the overall design of the underwater vehicle; according to the relevant data parameters, use three-dimensional modeling method to establish a full-scale geometric simulation model of the underwater vehicle structure. The geometric simulation model includes the form, structure, size, etc. of the inner and outer shells; the geometric simulation model does not need to be established as a solid model with thickness parameters, but only needs to be established as a shell model, and preferably the coordinate origin is adjusted to the geometric acoustic center of the geometric simulation model.

[0007] Step 2. Determine the time-domain acoustic wave information at all incident angles, and convert the incident time-domain acoustic wave information at all angles into the incident frequency-domain acoustic wave signal at all angles;

[0008] The incident time-domain acoustic wave information includes: setting the type, frequency, pulse width, sampling frequency, and emission interval of the incident time-domain pulse signal, so as to obtain the incident time-domain acoustic wave information. For the incident signal x(t) of the determined time-domain acoustic wave information at all angles, it is transformed into the frequency-domain signal X(f) through Fourier transform;

[0009] Step 3. Establish a coordinate system to determine the coordinates of the incident / receiving angles and describe them using the horizontal azimuth angle and the distance between the incident / receiving point and the equivalent geometric acoustic center of the underwater vehicle;

[0010] In the form of coordinates, a coordinate system is established with the equivalent geometric center of the underwater vehicle as the origin, and the coordinates of the incident point and the receiving point are represented on the horizontal plane by the horizontal azimuth angle; The transmitting / receiving points within the full angle range must simultaneously satisfy the far-field condition, that is, the distance r from the observation point to the equivalent geometric acoustic center of the underwater vehicle is not less than the ratio of the square of the total length L of the underwater vehicle to the acoustic wavelength λ; The incident acoustic wave is a point source, and under the far-field condition, it is approximately a plane wave when it reaches the target position; The scattered acoustic wave is regarded as the secondary radiation of the underwater vehicle's shell.

[0011] Step 4. Evaluate the reflection coefficient and transmission coefficient of the underwater vehicle's shell at different frequencies and all angles according to the wall thickness and material of the underwater vehicle's shell;

[0012] Generally, the structure of an underwater vehicle is mostly a single-shell or double-shell structure. Its reflection coefficient and transmission coefficient can be attributed to the acoustic propagation theory of layered elastic media. For any layer of medium, the acoustic wave potential function can be defined in the form of the longitudinal wave potential function and the flexural wave potential function for the acoustic pressure of adjacent two layers of media, and then the acoustic reflection and transmission coefficients are deduced;

[0013] Step 5. According to the shell form of the underwater vehicle, that is, two forms of single-shell structure or double-shell structure, as well as the shell reflection coefficient and transmission coefficient, establish an overall evaluation model of the full-angle target frequency-domain transfer function and calculate the full-angle target frequency-domain transfer function;

[0014] Step 5.1 Establish an evaluation model for the structural plate elements of the underwater vehicle; The inner and outer shells of the actual-scale geometric model of the underwater vehicle's structure are respectively divided into triangular surface meshes, and the topological information and node information of the triangular surface meshes are exported and saved separately;

[0015] Step 5.2 Read the node information and the triangular surface mesh file, draw the mesh models of the inner and outer shells of the underwater vehicle respectively. After setting the initial incident / receiving points, check the normal direction of the triangular surface mesh to ensure that the normal direction of the triangular surface mesh faces the outside of the underwater vehicle;

[0016] Step 5.3: Establish an acoustic scattering model for the underwater vehicle's hull and express it in the form of summing up surface elements. For a double-hull structure, consider the outer hull of the underwater vehicle as a thin steel elastic shell, taking into account the reflection and transmission of sound waves. At the same time, the sound waves transmitted through the outer hull to the inner hull are transmitted again and pass through the outer hull once more, and together with the first reflection of the outer hull, they are received by the receiving point. Finally, calculate the sum of the scattering contributions of all surface elements within the incident RF signal frequency band at all angles, that is, the target frequency-domain transfer function at all angles.

[0017] Step 6: Process the target frequency-domain transfer function at all angles and the incident RF-domain signal to obtain the co-located transmit-receive time-domain echo broadening characteristics of the underwater vehicle.

[0018] Multiply the target frequency-domain transfer function at all angles by the incident RF-domain signal to obtain the echo in the frequency domain at all angles. Finally, perform an inverse Fourier transform on the echo in the frequency domain at all angles to obtain the co-located transmit-receive time-domain echo broadening characteristics of the underwater vehicle. Use the cloud map of the sound pressure amplitude at the angle-echo time at all angles as the evaluation index for the co-located transmit-receive time-domain echo broadening characteristics of the underwater vehicle.

[0019] Step 7: Compare the co-located transmit-receive time-domain echo acoustic scattering characteristics obtained from the evaluation in Step 6 with the index requirements to obtain the evaluation conclusion of the co-located transmit-receive time-domain echo broadening characteristics of the underwater vehicle.

[0020] According to the requirements of the evaluation index system, calculate the co-located transmit-receive time-domain echo broadening characteristics of the underwater vehicle corresponding to the full-angle azimuth angles at the evaluation focus frequencies such as 500 Hz, 1 kHz, 3 kHz, 5 kHz, 10 kHz, etc. Compare and analyze the cloud map of the sound pressure amplitude at the angle-echo time with the design index to judge the risk of the index reachability.

[0021] The present invention provides a simulation and evaluation method for the time-domain echo broadening characteristics of a co-located transceiver of an underwater vehicle during the scheme design stage. According to the overall design scheme of the underwater vehicle, using the Kirchhoff approximation, the present invention takes the geometric model of the underwater vehicle, material parameters, and incident signals at all angles as inputs to evaluate the time-domain echo broadening characteristics of the co-located transceiver at all angles, and compares with the index requirements to achieve a method for risk assessment of the time-domain echo broadening characteristics index of the co-located transceiver. This evaluation method mainly includes six steps: analyzing the overall scheme design results of the underwater vehicle and sorting out the structural modeling parameters to establish a geometric simulation model, determining the acoustic wave signals in the frequency domain with all-angle incidence, establishing a coordinate system to determine the coordinates of all incident / receiving angles, evaluating the reflection coefficient and transmission coefficient of the underwater vehicle's hull at different frequencies and all angles, establishing an overall evaluation model of the target frequency-domain transfer function at all angles and calculating the target frequency-domain transfer function at all angles, and processing the target frequency-domain transfer function at all angles and the incident frequency-domain signal to obtain the time-domain echo broadening characteristics of the co-located transceiver of the underwater vehicle. This method can calculate the time-domain echo broadening characteristics of the co-located transceiver, has the advantages of fast calculation speed and reliable evaluation results, and can be widely applied to the evaluation and design fields of underwater weapons targets such as underwater vehicles, underwater unmanned submersibles, and torpedoes.

[0022] Advantageous effects: The method of the present invention is reasonable and feasible, overcomes the uncertainty in the evaluation of the time-domain echo broadening characteristics of the co-located transceiver of the current underwater vehicle, can realize the quantitative simulation calculation of the time-domain echo broadening characteristics of the co-located transceiver of single and double-hull underwater vehicles, and obtains an evaluation conclusion on the risk size of the time-domain echo broadening characteristics index of the overall scheme through comparison with the index requirements. Compared with the current evaluation method of the time-domain echo broadening characteristics of the co-located transceiver, it can greatly improve the rationality and accuracy of the evaluation results of the time-domain echo broadening characteristics of the overall scheme of the underwater vehicle.

[0023] The overall scheme transceiver co-located time-domain echo broadening characteristic evaluation method applicable to the overall scheme design stage of an underwater vehicle can, according to the overall design scheme of the underwater vehicle, take the geometric model of the underwater vehicle, material parameters, and incident signals at all angles as inputs to evaluate the time-domain echo broadening characteristics of the co-located transceiver at all angles, compare with the requirements of the time-domain echo broadening characteristics index of the co-located transceiver, and realize the evaluation of the risk size of the time-domain echo broadening characteristics index. Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the geometric model of the Benchmark underwater vehicle in a preferred embodiment of the simulation and evaluation method for the time-domain echo broadening characteristics of the co-located transceiver of the underwater vehicle described in the present invention;

[0025] Figure 2 is Figure 1Schematic diagram of the outer shell grid of the Benchmark underwater vehicle in the illustrated embodiment;

[0026] Figure 3 is Figure 1 Schematic diagram of the inner shell grid of the Benchmark underwater vehicle in the illustrated embodiment;

[0027] Figure 4 is Figure 1 Schematic diagram of the normal of the outer shell grid of the Benchmark underwater vehicle in the illustrated embodiment;

[0028] Figure 5 is Figure 1 Schematic diagram of the normal of the inner shell grid of the Benchmark underwater vehicle in the illustrated embodiment;

[0029] Figure 6 is Figure 1 Schematic diagram of the incident signal of the Benchmark underwater vehicle in the illustrated embodiment being a single - frequency signal with a frequency of 5000 Hz and a pulse width of 1 ms;

[0030] Figure 7 Figure 1 Schematic diagram of the incident signal of the Benchmark underwater vehicle in the illustrated embodiment being a single - frequency signal with a frequency of 10 kHz and a pulse width of 1 ms;

[0031] Figure 8 is Figure 1 Schematic diagram of the angle - echo time - acoustic pressure amplitude nephogram at all angles at a detection distance of 1000 m when the incident signal of the Benchmark underwater vehicle in the illustrated embodiment is a single - frequency signal with a frequency of 5 kHz and a pulse width of 5 ms;

[0032] Figure 9 is Figure 1 Schematic diagram of the angle - echo time - acoustic pressure amplitude nephogram at all angles at a detection distance of 1000 m when the incident signal of the Benchmark underwater vehicle in the illustrated embodiment is a single - frequency signal with a frequency of 10 kHz and a pulse width of 5 ms; Detailed implementation manners

[0033] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation manners.

[0034] The simulation and evaluation method for the time - domain echo broadening characteristics of the integrated transceiver underwater vehicle in this embodiment performs the following steps:

[0035] Step 1. Analyze the overall design results of the underwater vehicle and sort out the structural modeling parameters to establish a geometric simulation model;

[0036] Analyze the overall design results of the underwater vehicle, including the overall design specification, basic structure design specification, body line drawing, basic structure drawing, general arrangement drawing and other documents and drawing materials, as well as the form, size, shell thickness and other parameters of the inner and outer shell structures of the underwater vehicle related to the overall scheme of the underwater vehicle; according to the relevant data parameters, establish a full-scale geometric simulation model of the underwater vehicle structure by using the three-dimensional modeling method, and this geometric simulation model includes the forms, structures, sizes, etc. of the inner and outer shells; this geometric simulation model does not need to be established as a solid model with thickness parameters, but only needs to be established as a shell model, and preferably adjust the coordinate origin to the geometric acoustic center of the geometric simulation model.

[0037] Step 2. Determine the time-domain acoustic wave information at all incident angles, and convert the incident time-domain acoustic wave information at all angles into the incident frequency-domain acoustic wave signal at all angles;

[0038] Determining the incident time-domain acoustic wave information includes setting the types of incident time-domain pulse signals, such as typical single-frequency frequencies of 500 Hz, 1 kHz, 3 kHz, 5 kHz, 10 kHz, etc., setting the pulse width to 1 ms, 5 ms, etc., and the sampling frequency is generally more than 2.5 times the transmitting frequency. For the incident signal x(t) of the determined time-domain acoustic wave information at all angles, it is transformed into the frequency-domain signal X(f) through Fourier transform;

[0039] Step 3. Establish a coordinate system to determine the coordinates of the incident / receiving angles and describe them using the horizontal azimuth angle and the distance between the incident / receiving point and the equivalent geometric acoustic center of the underwater vehicle;

[0040] In the form of coordinates, establish a coordinate system with the equivalent geometric center of the underwater vehicle as the origin, and use the horizontal azimuth angle to represent the coordinates of the incident point and the receiving point on the horizontal plane; the transmitting / receiving points at all angles must simultaneously meet the far-field conditions, that is, the distance r from the observation point to the equivalent geometric acoustic center of the underwater vehicle is not less than the ratio of the square of the total length L of the underwater vehicle to the acoustic wavelength λ; the incident acoustic wave is a point source, and under the far-field conditions, it is approximately a plane wave when reaching the target position; the scattered acoustic wave is regarded as the secondary radiation of the underwater vehicle shell.

[0041] Step 4. Evaluate the reflection coefficient and transmission coefficient of the underwater vehicle shell at different frequencies and all angles according to the wall thickness and material of the underwater vehicle shell;

[0042] For the theoretical model calculation of the acoustic scattering problem of any multi-layer, for any layer l, define the following acoustic wave potential function:

[0043] φ l =[A l exp(iα l z)+B l exp(-ia l z)]exp[i(σx - ωt)] (1)

[0044] ψ t = [C t exp(iβ t z) + D t exp(-iβ t z)] exp[i(σx - ωt)] (2)

[0045] where φ l is the longitudinal wave potential function, and ψ t is the flexural wave potential function.

[0046] B l and D t are the amplitudes of the incident waves; A l and C t are the amplitudes of the reflected waves, and there are:

[0047]

[0048]

[0049] σ l = k t sinθ l (5)

[0050] where k l and K t are the wave numbers of the longitudinal wave and the flexural wave.

[0051] Through a series of derivation processes, the expression of the acoustic reflection coefficient can finally be obtained as follows:

[0052]

[0053] where,

[0054] C ij = F IJ - F 4J * F i1 / F 41 (7)

[0055] Z0 = ρ0c0 / cosθ0 (8)

[0056] Z n+1 = ρ n+1 c n+1 / cosθ n+1 (9)

[0057] According to the condition that the sum of the squares of the reflection coefficient and the transmission coefficient is 1 when ignoring losses, the transmission coefficient can be deduced from the above reflection coefficient;

[0058] Step 5. Based on the hull form of the underwater vehicle, i.e., single hull structure or double hull structure, as well as the reflection coefficient and transmission coefficient of the outer shell, establish an overall evaluation model for the full-angle target frequency-domain transfer function, and calculate the full-angle target frequency-domain transfer function;

[0059] Step 5.1 Establish an evaluation model for the structural plate elements of the underwater vehicle; respectively divide the inner and outer hulls of the actual-scale geometric model of the underwater vehicle's structure into triangular surface meshes, and export the topological information and node information of the triangular surface meshes, and save them separately;

[0060] Step 5.2 Read the node information and triangular surface mesh files, and draw the mesh models of the inner and outer hulls of the underwater vehicle respectively. After setting the initial incident / receiving points, check the normal direction of the triangular surface mesh to ensure that the normal direction of the triangular surface mesh faces the outside of the underwater vehicle;

[0061] Step 5.3 Establish an acoustic scattering model for the underwater vehicle's hull, and express it in the form of a sum of surface elements. For the double hull structure, regard the outer hull of the underwater vehicle as a thin steel elastic shell, considering the reflection and transmission of sound waves; at the same time, the sound waves transmitted through the outer hull to the inner hull are transmitted again, pass through the outer hull, and are received by the receiving point together with the first reflection of the outer hull. Finally, calculate the sum of the scattering contributions of all surface elements within the incident radio frequency domain signal band at all angles, that is, the target frequency-domain transfer function at all angles;

[0062] Step 5.4 In Step 5.3, the Kirchhoff approximation is used to establish an acoustic scattering model for the single hull underwater vehicle, that is, express the integral form of the Kirchhoff approximation method in the form of a sum of surface elements, regard the target surface of the underwater vehicle as absolutely rigid, do not consider the transmission of sound waves, and use the sum of surface elements to obtain the total scattered sound pressure;

[0063] The Kirchhoff formula gives the scattered sound field:

[0064]

[0065] In formula (10), φ s is the scattered sound pressure, r2 is the radius vector of the scattering point, n is the outer normal of the surface, and S is the surface of the scatterer. For high-frequency cases, it is usually assumed that:

[0066] a) The contribution of the geometric shadow area to the sound field can be ignored; the actual integration area is the part of the surface that is in the illuminated area when viewed from the emission point and the receiving point.

[0067] b) The surface of the scatterer satisfies the rigid boundary condition.

[0068] Further simplify to obtain the scattered sound pressure for the collocated transmitter and receiver:

[0069]

[0070] In Equation (11), the integral term can be transformed into an operation of surface element coordinates.

[0071] Step 5.5: Use the Kirchhoff approximation to establish an acoustic scattering model of a double-hull underwater vehicle. The basic principle is also to express the integral form of the Kirchhoff approximation method as a form of surface element summation. However, different from Step 5.4, the total acoustic scattering characteristic I of the underwater vehicle is equal to the echo intensity I out of the outer hull plus the inner hull, that is, the echo intensity I in of the inner hull. Among them, the echo intensity I out of the outer hull is generated by the plate with water on both sides, and the echo intensity I in of the inner hull is the pure inner hull (outer hull) echo intensity I in,0 when the outer hull (outer hull) is assumed to be non-existent and only the inner hull (inner hull) exists, plus the two transmission losses of the outer hull (outer hull). Define the reflection coefficient of the target at the azimuth angle as and the transmission coefficient as Use TS out and TS in,0 to represent the acoustic scattering characteristics of the outer hull (outer hull) and the pure inner hull (inner hull) respectively, and obtain the total echo intensity converted to a distance of 1 m

[0072]

[0073] In Equation (12), I i is the incident sound intensity; thus, the total acoustic scattering characteristic is

[0074]

[0075] Step 6: Process the target frequency-domain transfer function over all angles and the incident frequency-domain signal to obtain the time-domain echo broadening characteristic of the underwater vehicle with co-located transceiver;

[0076] Multiply the target frequency-domain transfer function over all angles by the incident frequency-domain signal to obtain the echo in the frequency domain over all angles. Finally, perform an inverse Fourier transform on the echo in the frequency domain over all angles to obtain the time-domain echo broadening characteristic of the underwater vehicle with co-located transceiver; use the angle-echo time sound pressure amplitude cloud map at all angles as the evaluation index for the time-domain echo broadening characteristic of the underwater vehicle with co-located transceiver

[0077] Step 7: Compare the time-domain echo broadening characteristic of the co-located transceiver obtained by evaluating and calculating in Step 6 with the index requirements to obtain the evaluation conclusion of the time-domain echo broadening characteristic index of the underwater vehicle with co-located transceiver.

[0078] According to the requirements of the evaluation index system, evaluate the results of the time-domain echo broadening characteristics of the transceiver co-location corresponding to the full azimuth angle at the evaluation focus frequencies of 500 Hz, 1 kHz, 3 kHz, 5 kHz, 10 kHz, etc., compare and analyze with the design indicators, and judge the risk of reachability of the indicators.

[0079] Figure 8 and Figure 9 are the sound pressure amplitude cloud maps of the angle-echo time corresponding to the Benchmark underwater vehicle at different frequency pulse widths and the same detection distance. The abscissa represents different incident angles, the ordinate represents the echo time, and the color represents the echo target strength value; taking the 0-degree azimuth as an example, the earliest echo time is around 1.3 s, because the detection distance is set to 1000 m, plus the geometric length of the model itself. Using the round-trip distance of detection and the propagation speed of sound waves underwater, that is, the time when the echo returns, the echo generated by the sound wave that reaches the head first. Around 1.31 s later, it is the echo generated by the bow rudders on both sides. The subsequent echoes represent the structures such as the conning tower and the stern rudder in turn. The angle-echo time sound pressure amplitude cloud map can intuitively show the structural characteristics of the underwater vehicle.

[0080] Thus, it can be seen that this method can evaluate the risk of the time-domain echo broadening characteristic index of the transceiver co-location for the underwater vehicle.

Claims

1. A simulation and evaluation method for the time-domain echo broadening characteristics of a combined transceiver underwater vehicle, characterized in that The steps include: Step 1. Determine the total length, shell form, shell wall thickness, material parameters of the geometric model of the underwater vehicle, and the coordinate origin of the geometric model of the underwater vehicle according to the overall design results of the underwater vehicle and the structural modeling parameters, and define this coordinate origin as the equivalent geometric acoustic center of the underwater vehicle; Step 2. Determine the time-domain acoustic wave information under all-angle incidence, and convert the incident time-domain acoustic wave information under all angles into the incident frequency-domain acoustic wave signal under all angles; Step 3. Determine the coordinates of the incident / receiving angle and describe them using the horizontal azimuth angle and the distance between the incident / receiving point and the equivalent geometric acoustic center of the underwater vehicle in Step 1; Step 4. Evaluate the reflection coefficient and transmission coefficient of the outer shell of the underwater vehicle at different frequencies under all angles according to the wall thickness and material of the outer shell of the underwater vehicle; Step 5. Establish an overall evaluation model of the target frequency-domain transfer function under all angles according to the shell form of the underwater vehicle, as well as the outer shell reflection coefficient and transmission coefficient, and calculate the target frequency-domain transfer function under all angles; Step 6. Multiply the target frequency-domain transfer function under all angles by the incident frequency-domain signal to obtain the echo in the frequency domain under all angles. Finally, through the inverse Fourier transform of the echo in the frequency domain under all angles, obtain the characteristics of the time-domain echo broadening of the transceiver co-located underwater vehicle; Step 7. Compare the characteristics of the time-domain echo broadening of the transceiver co-located obtained by evaluating and calculating in Step 6 with the index requirements to obtain the evaluation conclusion of the characteristics index of the time-domain echo broadening of the transceiver co-located underwater vehicle.

2. The simulation evaluation method for the transmit-receive co-located time-domain echo broadening characteristic of an underwater vehicle according to claim 1, wherein The overall design results of the underwater vehicle in Step 1 include the overall design specification, basic structure design specification, body plan, basic structure drawing, and general arrangement drawing. The structural modeling parameters include the inner and outer shell structural forms, dimensions, and shell thickness parameters related to the overall plan of the underwater vehicle; for structures without clear thickness parameters, refer to the relevant parameter values of the standard underwater vehicle.

3. The simulation and estimation method for the transmit-receive co-located time-domain echo broadening characteristic of an underwater vehicle according to claim 1, characterized in that The all angles in Step 2 refer to all angles from 0 to 360 degrees of the horizontal azimuth angle of the underwater vehicle; The incident time-domain acoustic wave information includes: setting the type, frequency, pulse width, and sampling frequency of the incident time-domain pulse signal to obtain the incident time-domain acoustic wave information, and converting it into the incident frequency-domain acoustic wave signal through Fourier transform.

4. The simulation and evaluation method for the transmit-receive co-located time-domain echo broadening characteristics of an underwater vehicle according to claim 1, wherein The transmitting / receiving points under all angles in Step 3 must simultaneously meet the far-field condition, that is, the distance r from the observation point to the equivalent geometric acoustic center of the underwater vehicle is not less than the ratio of the square of the total length L of the underwater vehicle to the acoustic wavelength λ.

5. The simulation and evaluation method for the time-domain echo broadening characteristic of a combined transceiver in an underwater vehicle according to claim 1, wherein The incident acoustic wave in Step 3 is a point source, and under the far-field condition, it is approximately a plane wave when it reaches the target position; the scattered acoustic wave is regarded as the secondary radiation of the underwater vehicle shell.

6. The simulation and evaluation method for the time-domain echo broadening characteristics of a combined transceiver of an underwater vehicle according to claim 1, characterized in that Step 5 also includes: Step 5.1 Establish an evaluation model of the structural plate element of the underwater vehicle; respectively divide the inner and outer shells of the geometric model of the actual scale of the underwater vehicle structure into triangular surface meshes, and export the topological information and node information of the triangular surface meshes, and save them separately; Step 5.2 Read the node information and triangular surface mesh file, and respectively draw the mesh models of the inner and outer shells of the underwater vehicle. After setting the initial incident / receiving points, check the normal direction of the triangular surface mesh to ensure that the normal direction of the triangular surface mesh faces the outside of the underwater vehicle; Step 5.3 Establish an acoustic scattering model for the underwater vehicle's shell and express it in the form of summation of surface elements. For the double-shell structure, regard the outer shell of the underwater vehicle as a thin steel elastic shell, considering the reflection and transmission of sound waves; at the same time, the sound waves transmitted through the outer shell to the inner shell are transmitted again, pass through the outer shell, and are received by the receiving point together with the first reflection of the outer shell. Finally, calculate the sum of the scattering contributions of all surface elements within the incident radio frequency domain signal frequency band at all angles, that is, the target frequency domain transfer function at all angles.

7. The simulation and evaluation method for the time-domain echo broadening characteristic of the integrated transceiver of an underwater vehicle according to claim 1, characterized in that In Step 7, use the angle-echo time sound pressure amplitude cloud map at all angles as the evaluation index for the transceiver co-located time domain echo broadening characteristics of the underwater vehicle.

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