Vector receiving array based on standard scatterer and sound wave propagation direction measuring method

Abstract

The invention belongs to the field of acoustics (underwater sound), provides a vector receiving array based on a standard reflector scattering sound field, and can complete measurement of a broadband sound wave propagation direction only by using two scalar hydrophones and a small rigid ball by using angular spectrum characteristics of standard reflector sound field distribution. The device is simple and stable in structure, can be used in measurement such as underwater sonar sound source level calibration, and has a wide application prospect.

Description

Technical Field

[0001] The invention relates to the field of measurement and testing, in particular to the field of acoustics (underwater acoustics), and mainly relates to a vector receiving array based on a standard scatterer and a method for measuring the propagation direction of sound waves. Background Art

[0002] Vector measurement of underwater sound fields is one of the important research topics in the field of hydroacoustics. In water, there are only longitudinal waves, that is, sound waves where the vibration direction of particles overlaps with the propagation direction. Therefore, as long as the propagation direction of the sound wave can be measured, the direction of the sound wave vibration velocity can be measured to complete the vector measurement.

[0003] At present, the devices that can be used to measure the propagation direction of sound waves include linear arrays, planar arrays, vector hydrophones, etc. The direction-finding principles of linear arrays and planar arrays are the same. They all use the law of sound propagation to calculate the propagation matrix according to the distribution of array elements, and then find the propagation direction by inverse operation of the propagation matrix. Linear arrays can only measure one-dimensional propagation direction information, while planar arrays can complete three-dimensional measurements. Vector hydrophones are divided into three types: pressure difference vector hydrophones, isochronous vector hydrophones, and micro-thermal flow vector hydrophones. Among them, pressure difference vector hydrophones and micro-thermal flow vector hydrophones can be installed with hard connections, while isochronous vector hydrophones are installed using hanging soft connections. The directivity of a linear array can be adjusted by changing the number of array elements and the distribution of array elements. Generally speaking, the larger the aperture, the higher the directivity, but it will be more difficult to retract and release, and the practicality will be reduced. The directivity curve of a vector hydrophone is generally in the shape of a figure 8, and the directivity can be improved by forming an array of vector hydrophones. For the same directivity, the aperture of the vector hydrophone array is smaller than that of the general hydrophone array, but the volume of the array is still large and the stability is also lower than that of the general hydrophone array. Summary of the invention

[0004] The purpose of the present invention is to further reduce the volume of the vector measurement array and to provide a vector receiving array based on a standard scatterer and a method for measuring the direction of sound wave propagation.

[0005] The object of the present invention is achieved through the following technical solutions: A vector receiving array based on a standard scatterer, comprising a standard scatterer, a scalar hydrophone A and a scalar hydrophone B, the scalar hydrophone A and the scalar hydrophone B are symmetrically mounted on both sides of the standard scatterer, and the scalar hydrophone A, the scalar hydrophone B and the standard scatterer are connected in a hard connection to ensure that the relative positions between the two hydrophones and the standard scatterer are fixed during use.

[0006] As a preferred technical solution, the scalar hydrophone A and the standard scatterer, as well as the scalar hydrophone B and the standard scatterer are fixedly connected via connecting rods to form a hard connection structure.

[0007] As a preferred technical solution, the standard scatterer is a rigid sphere, and the scalar hydrophone A and the scalar hydrophone B are the same hydrophones.

[0008] The present invention also provides a method for measuring the sound wave propagation direction using a vector receiving array based on a standard scatterer. When measuring the sound propagation direction, the vector receiving array utilizes the angular spectrum characteristics of the scattered sound field of the standard scatterer, compares the ratio of the sound pressure at the positions of scalar hydrophone A and scalar hydrophone B, and calculates the sound propagation direction information.

[0009] As a preferred technical solution, the specific steps include:

[0010] Step S1, placing a vector receiving array based on a standard scatterer at a certain depth underwater, and generating a scattered wave acoustic field after a plane wave hits a standard scatterer in a normal incident direction;

[0011] Step S2, collecting received sound wave signal data through scalar hydrophone A and scalar hydrophone B, and performing FFT processing on the effective time domain signal;

[0012] Step S3, selecting the frequency point with the highest signal-to-noise ratio, and recording the ratio of the amplitudes of scalar hydrophone A and scalar hydrophone B at the frequency point;

[0013] Step S4, calculating the ratio α of the hydrophone sound pressures corresponding to different incident angles, calculating the incident angle θ corresponding to the hydrophone sound pressure ratio according to formula (2), and finally determining the propagation direction of the sound wave;

[0014]

[0015] in, It is the scattered wave sound field generated when a plane wave hits a rigid ball at normal incidence.

[0016] The beneficial effects of the present invention are as follows: the present invention designs a vector receiving array based on the scattered sound field of a standard reflector, and utilizes the angular spectrum characteristics of the sound field distribution of the standard scatterer to complete the measurement of the propagation direction of broadband sound waves using only two scalar hydrophones and a rigid ball. The present invention has a simple and stable structure, can be used in underwater sonar sound source level calibration and other measurements, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art or ordinary technicians, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 Schematic diagram of the scattered sound field when a rigid ball with a radius of 0.1m encounters a plane wave with a frequency of 5000Hz.

[0019] Figure 2 It is a schematic diagram of the structure of the vector receiving array based on the standard scatterer of the present invention.

[0020] Figure 3 Schematic diagram of the curve of the sound pressure intensity received by two scalar hydrophones changing with the incident angle.

[0021] Description of the reference numerals: standard scatterer 1 , scalar hydrophone A2 , scalar hydrophone B3 , connecting rod 4 . DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0023] When a plane wave hits a rigid sphere at normal incidence, the resulting scattered wave acoustic field expression is:

[0024]

[0025] in,

[0026] It can be seen that the scattered sound field has obvious directivity, and the directivity index corresponding to different directions is also different. Through simulation, it can be seen more intuitively, such as Figure 1 As shown in the figure, the scattered sound field of a rigid ball with a radius of 0.1m encounters a plane wave with a frequency of 5000Hz.

[0027] The present invention designs a vector receiving array, including a standard scatterer 1, a scalar hydrophone A2 and a scalar hydrophone B3, wherein the standard scatterer 1 at the center is a rigid sphere, and two scalar hydrophones (standard scatterer 1 and scalar hydrophone A2) are symmetrically and rigidly installed on both sides of the sphere, and can be rigidly connected by a connecting rod 4, such as Figure 2 shown.

[0028] If the radius of the standard scatterer is 0.1m and the hydrophone is 0.1m away from the standard scatterer, then as the incident angle of the incident wave changes, the sound pressure intensity received by the two hydrophones changes as follows: Figure 3 shown.

[0029] The present invention adopts the sound wave propagation direction measurement method based on the vector receiving array of the standard scatterer, and its mechanism is: when measuring the sound propagation direction, the vector receiving array utilizes the angular spectrum characteristics of the scattered sound field of the standard scatterer, compares the ratio of the sound pressure at the position of the scalar hydrophone A2 and the scalar hydrophone B3, and calculates the sound propagation direction information.

[0030] The method for measuring the direction of sound wave propagation specifically comprises the following steps:

[0031] Step S1, placing a vector receiving array based on a standard scatterer at a certain depth underwater;

[0032] Step S2, collecting received sound wave signal data through scalar hydrophone A2 and scalar hydrophone B3, and performing FFT processing on the effective time domain signal;

[0033] Step S3, selecting the frequency point with the highest signal-to-noise ratio, and recording the ratio of the amplitudes of the scalar hydrophone A2 and the scalar hydrophone B3 at the frequency point;

[0034] Step S4: According to formula (1), the ratio α of the hydrophone sound pressures corresponding to different incident angles can be calculated, and according to formula (2), the incident angle θ corresponding to the hydrophone sound pressure ratio can be calculated, and finally the propagation direction of the sound wave can be determined. That is, by comparing the ratio of the sound pressures received by the hydrophone and comparing the calculation result of formula (2), the incident angle θ of the sound wave can be obtained.

[0035]

[0036] in, It is the scattered wave sound field generated when a plane wave hits a rigid ball at normal incidence.

[0037] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A vector receiving array based on a standard scatterer, characterized in that: The invention comprises a standard scatterer (1), a scalar hydrophone A (2) and a scalar hydrophone B (3), wherein the scalar hydrophone A (2) and the scalar hydrophone B (3) are symmetrically mounted on both sides of the standard scatterer (1), and the scalar hydrophone A (2), the scalar hydrophone B (3) and the standard scatterer (1) are connected in a hard connection to ensure that the relative positions of the two hydrophones and the standard scatterer are fixed during use.

2. The vector receiving array based on standard scatterers according to claim 1, characterized in that: The scalar hydrophone A (2) and the standard scatterer (1), as well as the scalar hydrophone B (3) and the standard scatterer (1) are fixedly connected via a connecting rod (4) to form a hard connection structure.

3. The vector receiving array based on standard scatterers according to claim 2, characterized in that: The standard scatterer (1) is a rigid sphere, and the scalar hydrophone A (2) and the scalar hydrophone B (3) are identical hydrophones.

4. A method for measuring the direction of sound wave propagation using a vector receiving array based on a standard scatterer as claimed in any one of claims 1 to 3, characterized in that: When measuring the sound propagation direction, the vector receiving array utilizes the angular spectrum characteristics of the scattered sound field of the standard scatterer, compares the ratio of the sound pressure at the position of the scalar hydrophone A (2) and the scalar hydrophone B (3), and calculates the sound propagation direction information.

5. The method for measuring the direction of sound wave propagation according to claim 4, characterized in that: The specific steps are as follows: Step S1, placing a vector receiving array based on a standard scatterer at a certain depth underwater, and generating a scattered wave acoustic field after a plane wave hits a standard scatterer (1) in a normal incident direction; Step S2, collecting received sound wave signal data through scalar hydrophone A (2) and scalar hydrophone B (3), and performing FFT processing on the effective time domain signal; Step S3, selecting a frequency point with the highest signal-to-noise ratio, and recording the ratio of the amplitudes of the scalar hydrophone A (2) and the scalar hydrophone B (3) at the frequency point; Step S4, calculating the ratio α of the hydrophone sound pressures corresponding to different incident angles, calculating the incident angle θ corresponding to the hydrophone sound pressure ratio according to formula (2), and finally determining the propagation direction of the sound wave; in, It is the scattered wave sound field generated when a plane wave hits a rigid ball at normal incidence.

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