An auxiliary measuring device for reflection coefficient of a shallow stratum profiler

Abstract

The auxiliary measuring device for the reflection coefficient of a shallow layer profiler provided by the present invention includes a three-dimensional experimental platform and a transducer fixed to the three-dimensional experimental platform. The transducer emits sound waves vertically upward. After the sound waves propagate in water, they are totally reflected by the still water surface. After the reflected sound waves propagate in water, they are received by the transducer again. By changing the distance between the transducer and the still water surface, a series of echo amplitude curves of sound signals at different distances are obtained to acquire the reflection coefficient of the shallow layer profiler. The auxiliary measuring device for the reflection coefficient of a shallow layer profiler provided by the present invention utilizes the open water characteristics of a deep-sea engineering experimental pool and the total reflection characteristics of the still water surface, uses the shallow layer profiler to obtain the reflection amplitude in water, combines the reflection amplitude of submarine sediments in the actual marine environment, and calculates the reflection coefficient of submarine sediments, thereby providing a reliable reference for the inversion of physical properties of submarine sediments and bottom sediment classification.

Description

Technical Field

[0001] The present invention relates to the technical field of sediment deposition acoustics in the ocean, and particularly to an auxiliary measurement device for the reflection coefficient of a shallow stratum profiler. Background Art

[0002] Using a shallow stratum profiler to detect the reflection coefficient of submarine sediments plays an important role in the inversion of physical parameters of submarine sediments, bottom sediment classification, and acoustic field modeling. Traditional shallow stratum profilers operate on the water surface. Utilizing the total reflection characteristics of the water surface, they receive the double reflection echoes of submarine sediments. By using the amplitudes of these two echoes and spherical wave scattering correction, the submarine reflection coefficient is calculated. The errors of this method first come from the water surface. In the actual marine environment, the disturbance of the water surface will affect the total reflection effect of the water surface on sound waves. Secondly, the change of the seabed topography will cause multi-angle scattering of sound waves, affecting the vertical reflection effect. At the same time, in order to meet the measurement depth requirements, existing shallow stratum profilers will use low-frequency sound waves. The resolution of low-frequency sound waves is limited, and whether the echo truly reflects the reflection characteristics of the submarine surface sediments will be affected by the sediment characteristics.

[0003] Using a submersible carrying a high-frequency shallow stratum profiler to conduct near-bottom detection of the reflection characteristics of submarine sediments is an effective means for accurately measuring the reflection coefficient of submarine sediments. After obtaining the reflection amplitude of the sediments, since the submersible is far from the water surface, it is impossible to utilize the total reflection characteristics of the water surface to obtain the secondary echo. This detection method requires the use of a laboratory auxiliary measurement device to measure the total reflection characteristics of the shallow stratum profiler in water in order to calculate the reflection coefficient of the sediments. Therefore, the auxiliary measurement device for the reflection coefficient of a shallow stratum profiler is an important experimental basis for accurately measuring the reflection coefficient of submarine sediments. Summary of the Invention

[0004] In view of this, it is necessary to provide an auxiliary measurement device for the reflection coefficient of a shallow stratum profiler that can accurately measure the reflection coefficient of submarine sediments in view of the defects existing in the prior art.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] An auxiliary measurement device for the reflection coefficient of a shallow stratum profiler includes: a three-dimensional experimental platform and a transducer fixed on the three-dimensional experimental platform. The transducer vertically emits sound waves upward. After the sound waves propagate in water, they are totally reflected by the calm water surface. The reflected sound waves are received by the transducer again after propagating in water. By changing the distance between the transducer and the calm water surface, a series of echo amplitude curves of sound signals at different distances are obtained to acquire the reflection coefficient of the shallow stratum profiler.

[0007] In some preferred embodiments, it further includes a sound velocity sensor fixed to the three-dimensional experimental platform. The sound velocity sensor is used to measure the sound velocity in water, and calibrate the distance between the emitting surface of the transducer and the still water surface according to the sound velocity in water and the time difference between sound wave emission and reception.

[0008] In some preferred embodiments, the three-dimensional experimental platform includes a bottom frame, suspension rings connected to the four corners of the bottom frame, a first steel wire rope connected to two of the suspension rings, a second steel wire rope connected to the other two suspension rings, a first hook connected to the first steel wire rope, and a second hook connected to the second steel wire rope.

[0009] In some preferred embodiments, it further includes an attitude sensor fixed to the three-dimensional experimental platform. The roll reading of the attitude sensor reaches the roll reading when the bottom frame is horizontally placed on the ground, and the pitch reading of the attitude sensor reaches the pitch reading when the bottom frame is horizontally placed on the ground. And the emitting surface of the transducer is parallel to the still water surface. Define the plane where the three-dimensional experimental platform is located as the reference plane. The rotation of the attitude sensor around the x-axis of the reference plane is roll, and the rotation of the attitude sensor around the y-axis of the reference plane is pitch.

[0010] In some preferred embodiments, the measurement accuracy of the roll and pitch of the attitude sensor is better than 0.1°.

[0011] In some preferred embodiments, the vertical lifting accuracy of the first hook and the second hook is not less than 1 mm.

[0012] In some preferred embodiments, the first hook is further connected with a steel tape plumb bob, and the length of the steel tape plumb bob is not less than the near-field distance L of the transducer.

[0013] In some preferred embodiments, the lengths of the first steel wire rope and the second steel wire rope ensure that the distance between the transducer and the water surface is not less than the near-field distance L of the transducer.

[0014] In some preferred embodiments, the bottom frame further includes a fixture, and the transducer is fixed on the fixture.

[0015] The advantages of the present invention adopting the above technical solutions are:

[0016] The auxiliary measurement device for the reflection coefficient of a shallow layer profiler provided by the present invention includes a three-dimensional experimental platform and a transducer fixed on the three-dimensional experimental platform. The transducer emits sound waves vertically upward. After the sound waves propagate in water, they are totally reflected by the still water surface. After the reflected sound waves propagate in water, they are received by the transducer again. By changing the distance between the transducer and the still water surface, a series of echo amplitude curves of sound signals at different distances are obtained to acquire the reflection coefficient of the shallow layer profiler. The auxiliary measurement device for the reflection coefficient of the shallow layer profiler provided by the present invention utilizes the open water characteristics of a deep-sea engineering experimental pool and the total reflection characteristics of the still water surface, obtains the reflection amplitude in water using the shallow layer profiler, combines the reflection amplitude of the seabed sediments in the actual marine environment, and calculates the reflection coefficient of the seabed sediments, thereby providing a reliable reference for the inversion of physical property parameters of seabed sediments and seabed classification. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 FIG. is a schematic structural diagram of an auxiliary measurement device for the reflection coefficient of a shallow layer profiler provided by an embodiment of the present invention.

[0019] Figure 2 FIG. is a front view of the auxiliary measurement device for the reflection coefficient of a shallow layer profiler provided by an embodiment of the present invention when operating in a deep-sea engineering experimental pool. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0021] Please refer to Figure 1 and Figure 2 FIG., which is a schematic structural diagram of an auxiliary measurement device for the reflection coefficient of a shallow layer profiler provided by an embodiment of the present invention, including: a three-dimensional experimental platform 1 and a transducer 3 fixed on the three-dimensional experimental platform 1.

[0022] The working mode of the auxiliary measurement device for the reflection coefficient of the shallow layer profiler provided in the above embodiment is as follows:

[0023] The transducer 3 emits sound waves vertically upward. After the sound waves propagate in water, they are totally reflected by the still water surface. The reflected sound waves are received by the transducer 3 again after propagating in water. By changing the distance between the transducer 3 and the still water surface, a series of echo amplitude curves of sound signals at different distances are obtained to acquire the reflection coefficient of the shallow layer profiler.

[0024] For example, in an actual ocean environment, the shallow layer profiler obtains the echo amplitude A of the seabed sediment. At this time, the distance between the emission surface of the transducer and the seabed sediment is H. According to the echo amplitude curve obtained by the auxiliary measurement device for the reflection coefficient of the shallow layer profiler, the echo amplitude B at a distance H from the still water surface is obtained, and the reflection coefficient of the seabed sediment is A / B.

[0025] In some preferred embodiments, it further includes a sound velocity sensor 5 fixed to the three-dimensional experimental platform 1. The sound velocity sensor 5 is used to measure the sound velocity in water, and according to the sound velocity in water and the time difference between sound wave emission and reception, the distance between the emission surface of the transducer 3 and the still water surface is calibrated.

[0026] Specifically, an external signal generator is used to record the emission and reception waveforms, and the time difference of the signal between the emission surface of the transducer 3 and the still water surface is obtained according to the emission and reception waveforms; the sound velocity sensor 5 is used to obtain the sound velocity in water, and the product of the time difference and the sound velocity divided by 2 is the distance between the emission surface of the transducer 3 and the still water surface.

[0027] In some preferred embodiments, the three-dimensional experimental platform 1 includes a bottom frame 2, suspension rings 7 connected to the four corners of the bottom frame 2, a first steel wire rope 8 connected to two of the suspension rings 7, a second steel wire rope 10 connected to the other two suspension rings 7, a first hook 9 connected to the first steel wire rope 8, and a second suspension ring 11 connected to the second steel wire rope 10.

[0028] Furthermore, the vertical lifting precision of the first hook 9 and the second hook 11 is not lower than 1 mm.

[0029] In some preferred embodiments, the first hook 9 is further connected with a steel tape plumb bob 12, and the length of the steel tape plumb bob 12 is not lower than the near-field distance L of the transducer 3.

[0030] In some preferred embodiments, the lengths of the first steel wire rope 8 and the second steel wire rope 10 ensure that the distance between the transducer 3 and the water surface is not lower than the near-field distance L of the transducer.

[0031] In some preferred embodiments, the bottom frame 2 further includes a fixture 4, and the transducer 3 is fixed on the fixture 4.

[0032] In some preferred embodiments, it further includes an attitude sensor 6 fixed to the three-dimensional experimental platform 1. The roll reading of the attitude sensor 6 reaches the roll reading when the bottom frame 2 is horizontally placed on the ground, and the pitch reading of the attitude sensor reaches the pitch reading when the bottom frame 2 is horizontally placed on the ground. And the emitting surface of the transducer 3 is parallel to the still water surface. Define the plane where the three-dimensional experimental platform 1 is located as the reference plane. The rotation of the attitude sensor 6 around the x-axis of the reference plane is roll, and the rotation of the attitude sensor around the y-axis of the reference plane is pitch.

[0033] Further, the measurement accuracy of the roll and pitch of the attitude sensor 6 is better than 0.1°.

[0034] Please refer to Figure 2 , before the experimental platform 1 enters the water, first make the bottom frame 2 horizontally sit on the ground, record the roll and pitch readings of the attitude sensor 6 at this time, use the first hook 9 and the second hook 11 to lift the bottom frame 2, adjust the first steel wire rope 8 and the second steel wire rope 10 to make the roll reading of the attitude sensor 6 reach the roll reading when the bottom frame 2 is horizontally placed on the ground, use the first hook 9 and the second hook 11 to lift the bottom frame 2 into the water, make the distance between the transducer 3 and the still water surface not less than the near-field distance L of the transducer 3, and judge the water depth through the scale of the steel ruler plumb bob 12. Respectively adjust the hook 9 and the hook 11 to make the pitch reading of the attitude sensor 6 reach the pitch reading when sitting horizontally on the ground. At this time, the emitting surface of the transducer 3 is parallel to the still water surface.

[0035] It can be understood that if the distance between the transducer 3 and the still water surface is changed, it is necessary to adjust the hook 9 and the hook 11 again until the readings of the attitude sensor 6 return to the horizontally placed state.

[0036] The auxiliary measuring device for the reflection coefficient of the shallow layer profiler provided by the present invention utilizes the open water characteristics of the deep-sea engineering experimental pool and the total reflection characteristics of the still water surface, obtains the reflection amplitude in the water using the shallow layer profiler, combines the reflection amplitude of the seabed sediment in the actual marine environment, and calculates the reflection coefficient of the seabed sediment, so as to provide a reliable reference for the inversion of the physical properties of the seabed sediment and the bottom sediment classification.

[0037] Of course, the auxiliary measuring device for the reflection coefficient of the shallow layer profiler of the present invention can also have various transformations and modifications, and is not limited to the specific structure of the above-mentioned embodiments. In short, the protection scope of the present invention should include those transformations, substitutions and modifications that are obvious to those of ordinary skill in the art.

Claims

1. An auxiliary measuring device for the reflection coefficient of a shallow layer profiler, characterized in that Comprising: A three-dimensional experimental platform and a transducer fixed to the three-dimensional experimental platform. The transducer emits sound waves vertically upward. After the sound waves propagate in water, they are totally reflected by the still water surface. The reflected sound waves are received by the transducer again after propagating in water. By changing the distance between the transducer and the still water surface, an echo amplitude curve of the acoustic signal at a series of distances is obtained to acquire the reflection coefficient of the shallow layer profiler. It further comprises a sound velocity sensor fixed to the three-dimensional experimental platform. The sound velocity sensor is used to measure the sound velocity in water. According to the sound velocity in water and the time difference between the sound wave emission and reception, the distance between the emission surface of the transducer and the still water surface is calibrated. The three-dimensional experimental platform includes a bottom frame, suspension rings connected to the four corners of the bottom frame, a first steel wire rope connected to two of the suspension rings, a second steel wire rope connected to the other two suspension rings, a first hook connected to the first steel wire rope, and a second hook connected to the second steel wire rope.

2. The auxiliary measuring device for reflection coefficient of a shallow layer profiler as described in claim 1, wherein The vertical lifting precision of the first hook and the second hook is not less than 1 mm.

3. The auxiliary measuring device for reflection coefficient of a shallow stratum profiler according to claim 1, characterized in that It further comprises an attitude sensor fixed to the three-dimensional experimental platform. The roll reading of the attitude sensor reaches the roll reading when the bottom frame is horizontally on the ground, and the pitch reading of the attitude sensor reaches the pitch reading when the bottom frame is horizontally on the ground. Moreover, the emission surface of the transducer is parallel to the still water surface. The plane where the three-dimensional experimental platform is located is defined as the reference plane. The rotation of the attitude sensor around the x-axis of the reference plane is roll, and the rotation of the attitude sensor around the y-axis of the reference plane is pitch.

4. The shallow layer profiler reflection coefficient auxiliary measurement device according to claim 3, characterized in that, The measurement precision of the roll and pitch of the attitude sensor is better than 0.1°.

5. The shallow layer profiler reflection coefficient auxiliary measurement device according to claim 4, wherein, The first hook is further connected with a steel tape weight, and the length of the steel tape weight is not less than the near-field distance of the transducer.

6. The shallow layer profiler reflection coefficient auxiliary measurement device according to claim 5, wherein The lengths of the first steel wire rope and the second steel wire rope ensure that the distance between the transducer and the water surface is not less than the near-field distance of the transducer.

7. The auxiliary measuring device for reflection coefficient of a shallow layer profiler according to claim 5, characterized in that The bottom frame further includes a fixture, and the transducer is fixed to the fixture.

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