Method and system for measuring target strength based on boundary acoustic reflection

Abstract

The present invention discloses a method and a system for self-measurement of target strength based on boundary acoustic reflection. The method for self-measurement of target strength is as follows: a sonar transmitter / receiver mounted on a target to be measured measures acoustic intensity I s Step 1: transmitting a sound wave A of a vertical boundary; Step 2: receiving the reflection of the sound wave A from the vertical boundary with a sonar transmitting and receiving device, time-reversing the received sound wave, and transmitting the inverted sound wave B' to the vertical boundary; Step 3: receiving the reflection of the sound wave B' from the vertical boundary with a sonar transmitting and receiving device, and measuring the acoustic intensity I of the received sound wave C. i Step 3: A sonar transmitting and receiving device receives scattered sound waves from the target excited by the sound wave C and reflected by the vertical boundary, time-reverses the received sound waves, and transmits the inverted sound wave D' to the vertical boundary. Step 4: The sonar transmitting and receiving device receives the reflection of the sound wave D' by the vertical boundary and calculates the acoustic intensity I of the received sound wave E. T Step 5 to calculate the target strength TS of the target to be measured: ##EQU00017## and step 6 of calculating the target strength. This method does not require any test equipment, but instead realizes self-measurement of target strength using only sonar transmitting and receiving equipment mounted on the target itself.

Description

[Technical field]

[0001] The present invention relates to the field of acoustic measurement technology, and in particular to a method and system for self-measurement of target strength based on boundary acoustic reflection. [Background technology]

[0002] With the development of underwater acoustic technology, the noise level of sonar targets is becoming lower and lower, some of which are close to or even lower than the noise level of the marine environment in level 3 sea conditions, making it difficult to detect using passive sonar. Active sonar is the most effective way to detect such quiet targets. In active sonar detection technology, the stealth performance of sensitive targets and the detection performance of sonar equipment must both be reflected and verified from the strength of the target echo. As an important sonar parameter, target strength determines the detection performance of sonar. Underwater target strength is obtained by the acoustic scattering test of the target. The current acoustic scattering test of large underwater targets requires the use of ships to separately place the test equipment, and the results are easily affected by the scattering characteristics of the target and the shallow water environment, the operation is complicated, the measurement task is heavy, the period is long, and the measurement fluctuation is large, which affects the robustness of the obtained target strength value. Summary of the Invention [Means for solving the problem]

[0003] An object of the present invention is to provide a method and system for self-measurement of target strength based on boundary acoustic reflection, which does not require test equipment and can be realized only by sonar transmitting and receiving equipment mounted on the target to be measured itself.

[0004] The technical solutions are as follows: In one aspect of the present invention, a target strength self-measurement method based on boundary acoustic reflection is disclosed, the method includes the following steps:

[0005] S1, using a sonar transmitter / receiver mounted on the target itself, acoustic intensity I s The sound wave A is transmitted, and the distance dis between the vertical boundary and the target is dis ≧ L 2 / λ, where L is the maximum linearity of the target and λ is the wavelength of the acoustic wave.

[0006] S2, the sonar transmitting / receiving equipment receives the reflection of sound wave A by the vertical boundary, assumes that what is received is sound wave B, time-reverses sound wave B to obtain sound wave B', and transmits sound wave B' to the vertical boundary.

[0007] S3, the sonar transmitting / receiving device receives the reflection of the sound wave B' from the vertical boundary, assumes that what is received is the sound wave C, and calculates the sound intensity I based on the signal of the sound wave C. i Calculate.

[0008] S4, the sonar transmitting and receiving equipment receives a scattered sound wave D of the target excited by the sound wave C and reflected by the vertical boundary, time-reverses the sound wave D to obtain a sound wave D', and transmits the sound wave D' to the vertical boundary.

[0009] S5, the sonar transmitting / receiving device receives the reflection of the sound wave D' from the vertical boundary, assumes that what is received is the sound wave E, and calculates the sound intensity I based on the signal of the sound wave E. T Calculate.

[0010] S6, target strength TS of the measurement target:

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[0011] Preferably, the vertical boundary is a cliff wall.

[0012] Preferably, the sonar transmitting and receiving equipment is a two-way transducer.

[0013] Preferably, the measurement target is located in water.

[0014] Preferably, the sonar transmitting and receiving equipment transmits sound waves horizontally to a vertical boundary.

[0015] In another aspect, the present invention further discloses a target strength self-measurement system for implementing the above method, the target strength self-measurement system is provided on a target to be measured, and includes a sonar transceiver device for transmitting and receiving an acoustic signal, a signal time reversal module for time-reversing the acoustic signal, an acoustic intensity acquisition module for calculating the acoustic intensity of the acoustic signal, and a target intensity calculation module for calculating the target strength of the target to be measured.

[0016] The steps for calculating the target intensity of the measurement target are as follows: The sonar transmitter and receiver is placed on the vertical boundary with an acoustic intensity of I s The sound wave A is transmitted, and the distance dis between the vertical boundary and the target is dis ≧ L 2 / λ, where L is the maximum linearity of the target and λ is the wavelength of the sound wave. The sonar transmitter / receiver receives the reflection of sound wave A from a vertical boundary and assumes that what is received is sound wave B. The signal time reversal module time-reverses the sound wave B to obtain sound wave B'; The sonar transmitter transmits sound waves B' to the vertical boundary, The sonar transmitter / receiver receives the reflection of sound wave B' from a vertical boundary and assumes that what is received is sound wave C. The acoustic intensity acquisition module measures the acoustic intensity I of sound wave C. i Calculate The sonar transmitting and receiving device receives scattered sound waves D from the target excited by the sound waves C and reflected by the vertical boundary; The signal time reversal module time-reverses the sound wave D to obtain a sound wave D'; The sonar transmitter / receiver transmits sound waves D' to the vertical boundary, The sonar transmitter / receiver receives the reflection of sound wave D' from a vertical boundary and assumes that what is received is sound wave E. The acoustic intensity acquisition module measures the acoustic intensity I of sound wave E.T Calculate The target strength calculation module calculates the target strength TS of the target being measured:

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[0017] The target strength self-measurement method and target strength self-measurement system based on boundary acoustic reflection disclosed in the present invention have the following advantages: (1) It does not require independent test equipment, but uses sonar transmitting and receiving equipment mounted on the target to be measured itself; (2) It does not require strict free-field test conditions, and utilizes the acoustic focusing principle of active time reversal mirror technology to form an incident sound field similar to a plane wave, meets the incident acoustic conditions in target strength test, and utilizes the channel matching principle of active time reversal mirror technology to excite the test sound field of the target, calibrate the channel effect, improve the signal-to-target echo ratio, and reduce the measurement error. [Brief description of the drawings]

[0018] [Figure 1] 1 is a flow chart of a target strength self-measurement method based on boundary acoustic reflection disclosed in the present invention. [Diagram 2] 1 is a schematic diagram of an implementation scenario of a target strength self-measurement method based on boundary acoustic reflection in an embodiment; FIG. [Diagram 3] FIG. 1 is a schematic diagram of a target strength self-measurement system based on boundary acoustic reflection disclosed in the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The present invention will be further described below in combination with the drawings and specific embodiments.

[0020] The present invention discloses a method for target strength self-measurement based on boundary acoustic reflection, which includes the following steps, as shown in FIG. S1, using a sonar transmitter / receiver mounted on the target itself, acoustic intensity I s The sound wave A is transmitted, and the distance dis between the vertical boundary and the target is dis ≧ L 2 / λ, where L is the maximum linearity of the target and λ is the wavelength of the acoustic wave.

[0021] In this embodiment, the measurement target is located underwater, and is provided with a bi-directional transducer that can transmit directional sound waves and convert the received sound waves into electrical signals, as shown in Figure 2. In this embodiment, the vertical boundary is a cliff wall, making full use of the underwater environment in which the measurement target exists.

[0022] S2, the sonar transmitting / receiving equipment receives the reflection of sound wave A by the vertical boundary, assumes that what is received is sound wave B, time-reverses sound wave B to obtain sound wave B', and transmits sound wave B' to the vertical boundary.

[0023] S3, the sonar transmitting / receiving device receives the reflection of the sound wave B' from the vertical boundary, assumes that what is received is the sound wave C, and calculates the sound intensity I based on the signal of the sound wave C. i Calculate.

[0024] S4, the sonar transmitting and receiving equipment receives a scattered sound wave D of the target excited by the sound wave C and reflected by the vertical boundary, time-reverses the sound wave D to obtain a sound wave D', and transmits the sound wave D' to the vertical boundary.

[0025] S5, the sonar transmitting / receiving device receives the reflection of the sound wave D' from the vertical boundary, assumes that what is received is the sound wave E, and calculates the sound intensity I based on the signal of the sound wave E. T Calculate.

[0026] In the above step, the sonar transmitting and receiving equipment transmits sound waves horizontally to the vertical boundary, so that the vertical boundary can reflect the sound waves better.

[0027] S6, target strength TS of the measurement target:

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[0028] The proof of the above target strength calculation formula is as follows. Sound Intensity I s Assume that the time domain signal of sound wave A is s(t) and the time domain signal of sound wave B is s'(t),

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[0029] By time-reversing the sound wave s'(t), we obtain sound wave B', whose time domain signal is

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[0030] This embodiment discloses a self-measurement system for realizing the above-mentioned target strength self-measurement method. As shown in Figure 3, the self-measurement system is installed in the target to be measured, and includes a sonar transceiver device 1 for transmitting and receiving a sonic signal, a signal time reversal module 2 for time-reversing the sonic signal, an acoustic intensity acquisition module 3 for calculating the acoustic intensity of the sonic signal, and a target intensity calculation module 4 for calculating the target intensity of the target to be measured.

[0031] The steps for calculating the target intensity of the measurement target are as follows: The sonar transmitter and receiver is placed on the vertical boundary with an acoustic intensity of I s The sound wave A is transmitted, and the distance dis between the vertical boundary and the target is dis ≧ L 2 / λ, where L is the maximum linearity of the target and λ is the wavelength of the sound wave. The sonar transmitter / receiver receives the reflection of sound wave A from a vertical boundary and assumes that what is received is sound wave B. The signal time reversal module time-reverses the sound wave B to obtain sound wave B'; The sonar transmitter transmits sound waves B' to the vertical boundary, The sonar transmitter / receiver receives the reflection of sound wave B' from a vertical boundary and assumes that what is received is sound wave C. The acoustic intensity acquisition module measures the acoustic intensity I of sound wave C. i Calculate The sonar transmitting and receiving device receives scattered sound waves D from the target excited by the sound waves C and reflected by the vertical boundary; The signal time reversal module time-reverses the sound wave D to obtain a sound wave D'; The sonar transmitter / receiver transmits sound waves D' to the vertical boundary, The sonar transmitter / receiver receives the reflection of sound wave D' from a vertical boundary and assumes that what is received is sound wave E. The acoustic intensity acquisition module measures the acoustic intensity I of sound wave E. T Calculate The target strength calculation module calculates the target strength TS of the target being measured:

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Claims

1. A method for self-measurement of target strength based on boundary acoustic reflection, comprising: Using sonar transmitter and receiver mounted on the target itself, acoustic intensity I is measured at the vertical boundary. ｓ A step of transmitting a sound wave A of, wherein the distance dis between the vertical boundary and the target is dis ≧ L ２ / λ, where L is the maximum linearity of the target and λ is the wavelength of the acoustic wave; Step S2, in which the sonar transceiver receives a reflection of the sound wave A from a vertical boundary, assumes that what is received is a sound wave B, time-reverses the sound wave B to obtain a sound wave B', and transmits the sound wave B' to the vertical boundary; The sonar transceiver receives the reflection of the sound wave B' from the vertical boundary, assumes that what is received is sound wave C, and calculates an acoustic intensity I based on the signal of sound wave C. ｉ S3: calculating Step S4: the sonar transceiver receives a scattered sound wave D from the target excited by the sound wave C and reflected by the vertical boundary, time-reverses the sound wave D to obtain a sound wave D', and transmits the sound wave D' to the vertical boundary; The sonar transceiver receives the reflection of the sound wave D' from the vertical boundary, assumes that what is received is a sound wave E, and calculates an acoustic intensity I based on the signal of the sound wave E. Ｔ Step S5 of calculating Target strength TS of the measurement target: ##EQU00015## and (S6) calculating the boundary acoustic reflection-based target strength self-measurement method.

2. The method for target strength self-measurement based on boundary acoustic reflection according to claim 1, characterized in that the vertical boundary is a cliff wall.

3. The method for target strength self-measurement based on boundary acoustic reflection as claimed in claim 1, characterized in that the sonar transmitting and receiving device is a dual-purpose transducer.

4. The method for self-measurement of target strength based on boundary acoustic reflection as claimed in claim 1 , wherein the measurement target is located in water.

5. The method for self-measurement of target strength based on boundary acoustic reflection as claimed in claim 1, characterized in that the sonar transmitting and receiving equipment transmits sound waves horizontally to a vertical boundary.

6. A target strength self-measurement system based on boundary acoustic reflection, comprising: a sonar transceiver device for transmitting and receiving an acoustic signal, the sonar transceiver device being provided on a target to be measured; a signal time reversal module for time-reversing the acoustic signal; an acoustic intensity acquisition module for calculating an acoustic intensity of the acoustic signal; and a target strength calculation module for calculating a target strength of the target to be measured, In the step of calculating the target strength of the measurement target, The sonar transmitting and receiving equipment transmits sound intensity I ｓ The sound wave A is transmitted, and the distance dis between the vertical boundary and the target is dis ≧ L ２ / λ, where L is the maximum linearity of the target and λ is the wavelength of the acoustic wave; The sonar transmitting and receiving equipment receives the reflection of sound wave A by a vertical boundary and assumes that what is received is sound wave B. The signal time reversal module time-reverses the sound wave B to obtain sound wave B'; The sonar transmitting and receiving equipment transmits a sound wave B' to the vertical boundary; The sonar transmitting and receiving equipment receives the reflection of sound wave B' from a vertical boundary and assumes that what is received is sound wave C; The acoustic intensity acquisition module acquires the acoustic intensity I of the sound wave C. ｉ Calculate The sonar transmitting and receiving device receives scattered sound waves D from the target excited by the sound waves C and reflected by the vertical boundary; The signal time reversal module time-reverses the sound wave D to obtain a sound wave D', The sonar transmitting and receiving equipment transmits sound waves D' to the vertical boundary; The sonar transmitting and receiving equipment receives the reflection of the sound wave D' by the vertical boundary and assumes that what is received is the sound wave E; The acoustic intensity acquisition module acquires the acoustic intensity I of the sound wave E. Ｔ Calculate The target strength calculation module calculates the target strength TS of the target to be measured: ##EQU00016## A target strength self-measurement system based on boundary acoustic reflection, characterized in that:

7. The target strength self-measurement system based on boundary acoustic reflection according to claim 6, characterized in that the vertical boundary is a cliff wall.

8. 7. The target strength self-measurement system based on boundary acoustic reflection as claimed in claim 6, wherein said sonar transmitting and receiving equipment is a two-way transducer.

9. The target strength self-measurement system based on boundary acoustic reflection as claimed in claim 6, wherein the measurement target is located underwater.

10. The target strength self-measurement system based on boundary acoustic reflection as claimed in claim 6, characterized in that the sonar transmitting and receiving equipment transmits sound waves horizontally to a vertical boundary.

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