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Hydrophone test approach for ocean sound field phase velocity

A hydrophone and phase velocity technology, applied in the direction of measuring propagation velocity, instruments, measuring devices, etc., can solve the problems of impossible ocean sound field phase velocity test, difficulty in determining the reference phase, and high cost of acquisition

Inactive Publication Date: 2008-04-02
INST OF ACOUSTICS CHINESE ACAD OF SCI
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  • Application Information

AI Technical Summary

Problems solved by technology

[0006] These methods all have a major premise, that is, the distance between the sound source and the receiving point must be accurately known, which is often difficult to obtain or expensive in the marine environment
The reason that directly restricts the application of this method to the ocean sound field is that due to the limitation of the transmitting transducer, at present, only light bulbs, air guns and other sound sources can be used to produce broadband pulse sound sources. Therefore, the transmission waveform cannot be determined. If the waveform is unknown, it is difficult to determine the reference phase of each normal wave at different frequencies, so that the phase velocity cannot be obtained
In this way, it is impossible to use the existing technology to realize the phase velocity test of the ocean acoustic field

Method used

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  • Hydrophone test approach for ocean sound field phase velocity
  • Hydrophone test approach for ocean sound field phase velocity
  • Hydrophone test approach for ocean sound field phase velocity

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0077] Embodiment 1 uses 2 test ships to complete the ocean acoustic field phase velocity test

[0078] As shown in Figure 6, two test ships are used to complete the ocean acoustic field phase velocity test: one ship is used to receive signals, which is called the receiving ship, and the other ship is responsible for transmitting broadband pulses, called the transmitting ship.

[0079] The receiving ship deploys the hydrophone array on the seabed and connects it with the data acquisition system on the ship through a transmission cable. The number of hydrophones in the array is not limited, but it should be ensured that the distance of each pair of hydrophones used to calculate the phase velocity along the transmission pulse propagation direction satisfies the constraints of formula (11). The transmitting ship transmits the signal, and the receiving ship receives the signal, processes the signal, and obtains the test result. The test steps are as follows:

[0080] 1) Park the...

Embodiment 2

[0086] Embodiment 2 is completed by cooperating with fixed buoys and launching ships

[0087] As shown in Figure 7, two hydrophones are deployed on the buoy platform in the water, and the buoy is anchored to the seabed. The hydrophone is connected to the buoy, and the launching ship sends a communication command in advance to start the buoy to perform the phase velocity test working state, and then transmits a pulse signal, and the buoy receives the signal through N (N>2) hydrophone arrays, and processes the signal to obtain different The phase velocity curve of the normal wave, and finally the processing results are sent to the base station wirelessly. This method is suitable for the application background of long-term monitoring of fixed sea areas for existing buoy platforms. The test steps are as follows:

[0088] 1) Park the launching ship in the sea area required for testing, more than 2km away from the hydrophone of the buoy.

[0089]2) The launching ship sends a comm...

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Abstract

The invention discloses a method for testing sea sound field phase velocity by hydrophone, which comprising the following steps of: picking up normal-modes from the emission signals received by two hydrophones arranged along the spreading direction; carrying out 800-1000Hz band filtering and cross correlation calculation on No. 1 normal-mode received by the two hydrophones to obtain the time delay corresponding to the enveloping maximum point of cross correlation curve and multiplying the time delay by the a reference sound velocity to obtain an estimated distance between the two hydrophones; carrying out narrow-band filtering and cross correlation calculation on the normal modes of the same number to obtain the time delay of cross correlation which is the phase delay, the time delay of the enveloping maximum point of cross correlation which is the envelope delay and the phase velocity corresponding to the normal mode at the central frequency is equal to the phase delay at the estimated distance. The invention has the advantages that hydrophones are convenient to arrange on the same water level in the seabed; except sound speed of sea water, other sound field parameters are not necessary to foresee, thereby simplifying work amount and the test results are of high precision.

Description

technical field [0001] The invention belongs to a method for testing the phase velocity of the ocean sound field in the field of ocean engineering hydroacoustic detection, in particular to a hydrophone test method for the phase velocity of the ocean sound field. Background technique [0002] Due to the non-uniformity of the propagation medium, multi-mode propagation and dispersion phenomena occur during the propagation of sound waves. Therefore, it is impossible to accurately describe the propagation of sound waves by using the reference speed of sound in the general sense. According to the propagation velocity of the wave envelope envelope and the propagation velocity of the equiphase point, the sound velocity is divided into group velocity and phase velocity. Regarding the test methods of the group velocity and phase velocity of the sound field, in the application fields such as ultrasonic flaw detection, there are some discussions on the propagation of ultrasonic waves in...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01H5/00
Inventor 林京
Owner INST OF ACOUSTICS CHINESE ACAD OF SCI
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