CN110274613A - A kind of laboratory testing device and method suitable for acoustic wave tide measuring instrument - Google Patents

Abstract

The invention belongs to the technical field of marine science and relates to a laboratory detection device for an acoustic wave and tide meter. A laboratory detection device suitable for acoustic wave and tide measuring instruments, including a test water tank, a fixed bracket, an acoustic transducer array, a signal acquisition and processing box and a control system, and the acoustic transducer array is installed on the top inside of the fixed bracket The fixed bracket is placed in the test water tank; the acoustic transducer array is connected to the signal acquisition and processing box through cables, and the signal acquisition and processing box is connected to the control system through data lines. The laboratory detection device and method for the acoustic wave and tide measuring instrument of the present invention can detect the performance of the acoustic wave and tide measuring instrument in the laboratory. Inspection requirements, eliminating the process of pool test and field test, saving a lot of manpower and material resources.

Description

A laboratory detection device and method suitable for acoustic wave and tide measuring instruments

technical field

The invention belongs to the technical field of acoustic wave and tide meters, and relates to a laboratory detection device of an acoustic wave and tide meter.

Background technique

The study of ocean waves has always been an important research content in the field of ocean engineering. Accurate and real-time ocean wave measurement is an important requirement for ship navigation, ocean engineering, ocean forecasting, disaster prevention and mitigation, and navigation safety. Waves are one of the important contents of physical oceanography research.

The invention patent "An Acoustic Wave and Tide Measuring Instrument and Measurement Method" independently developed by the Institute of Marine Instrumentation, Shandong Academy of Sciences with the application number 201711270378.3 has four acoustic transducers, one vertical acoustic transducer in the center, and three inclined Transducers, four acoustic transducers measure the undulation of waves at four different locations in space. The wave height is calculated by using the measured value of the vertical beam, and then the wave period is obtained. In the process of wave propagation, the arrival time of waves at each measuring point is different, that is, the original wave signals measured by different measuring points have time delay differences, and the wave direction information can be analyzed by analyzing the time delay differences of different beam signals.

Under the existing technical conditions, the performance index inspection of acoustic wave measuring instruments generally needs to be verified by comparative tests in the field. It consumes a lot of manpower and material resources, is costly, and takes a long time.

Contents of the invention

The object of the present invention is to provide a laboratory detection device suitable for acoustic wave and tide measuring instruments, which can simulate the original data under different wave conditions, and can realize the acoustic wave under laboratory conditions by comparing the simulated value with the measured value. The detection purpose of the wave and tide measuring instrument does not need to go to the field for comparative tests, which saves a lot of manpower and material resources.

In order to achieve the above object, the technical solution adopted by the present invention is: a laboratory detection device suitable for acoustic wave and tide measuring instruments, including a test water tank, a fixed bracket, an acoustic transducer array, a signal acquisition and processing box and a control system, the The acoustic transducer array is installed on the inside of the top of the fixed bracket; the fixed bracket is placed in the test water tank; the acoustic transducer array is connected to the signal acquisition and processing box through cables, and the signal acquisition and processing box is connected to the signal acquisition and processing box through data lines. Control system connection.

Further, the acoustic transducer array is composed of four acoustic transducers that transmit and receive together, one of which is located in the center, and the other three are equally spaced on the periphery.

Further, the signal acquisition and processing box includes a transceiver circuit board and a signal control board, the transceiver circuit board is used to realize the transmission and reception of four transducer signals, and the signal control board controls the transmission mode and reception mode of the acoustic transducer switch.

Further, the control system is used to control the start/stop of the detection device, and the settings of detection conditions, detection time, and wave height, wave period, and wave direction values in the detection conditions.

Further, the control system includes a simulation model, and the wave height, wave period, and wave direction values in the detection conditions are set according to the simulation model.

Further, the control system includes a performance evaluation module, which is used to compare the measured value of the acoustic wave and tide measuring instrument with the simulated value, so as to evaluate whether the measured data is accurate.

In order to achieve the purpose of the present invention, the present invention also provides a laboratory detection method of an acoustic wave and tide measuring instrument, comprising the following steps:

(1) Place the detection above the acoustic tide meter to be tested, and place the two in the test water tank to ensure that the acoustic transducer array of the acoustic wave tide meter and the detection device is below the water surface;

(2) The measurement period is 2s. In a measurement period, the acoustic wave and tide measuring instrument is first in the transmitting mode, and the detection device is in the receiving mode. Transmit signal; after the detection device receives the signal, the acoustic wave and tide measuring instrument will switch to the receiving mode, and the detection device will switch to the transmitting mode, and the echo simulation model will be selected in the detection device to simulate the echo and transmit; the acoustic wave and tide measuring instrument will receive the signal from the detection The transmission signal of the device is used to calculate the real-time wave height value; the above process is repeated in the next cycle;

(3) Calculate the wave direction spectrum and wave eigenvalue every time the measurement time accumulates for one full hour;

(4) Compare the wave direction spectrum and wave eigenvalues calculated by the acoustic wave and tide measuring instrument with the simulation model, calculate the average error, and evaluate whether the parameter measurement is accurate according to the comparison between the average error and the measurement accuracy.

The laboratory detection device and method for the acoustic wave and tide measuring instrument of the present invention can detect the performance of the acoustic wave and tide measuring instrument in the laboratory. Inspection requirements, eliminating the process of pool test and field test, saving a lot of manpower and material resources.

Description of drawings

Fig. 1 is the structural connection diagram of the laboratory detection device applicable to the acoustic wave and tide measuring instrument of the present invention;

Fig. 2 is the flow chart of the laboratory detection method of the acoustic wave and tide measuring instrument of the present invention;

Fig. 3 is a schematic diagram of the emission and reception sequence of the acoustic wave and tide measuring instrument and the detection device;

Fig. 4 is a schematic diagram of a set of assumed original wave data;

Fig. 5 is a three-dimensional schematic diagram of an echo simulation model;

Fig. 6 is a schematic plan view of the echo simulation model (assuming that the wave directions are 0 degree, 90 degree, 180 degree and 270 degree respectively).

Detailed ways

The laboratory detection device and method applicable to the acoustic wave and tide measuring instrument of the present invention will be further elaborated and illustrated below in conjunction with the accompanying drawings and embodiments.

As shown in Fig. 1, the laboratory detection device applicable to the acoustic wave and tide measuring instrument of the present invention is mainly composed of a test water tank 1, a fixed bracket 2, an acoustic transducer array 4, a signal acquisition and processing box 6 and a host computer 7 . The acoustic transducer array 4 is installed on the inside of the top of the fixed bracket 2 . The fixed bracket 2 is made of stainless steel. The acoustic transducer array 4 is connected to the signal acquisition and processing box 6 through the cable 5, and the signal acquisition and processing box 6 is connected to the host computer 7 through the data line.

The acoustic transducer array 4 of the detection device is composed of four acoustic transducers combined with transmitting and receiving. The working frequency of the transducer is the same as that of the transducer array of the acoustic wave and tide measuring instrument, and can receive the acoustic wave and tide At the same time, the detection device can simulate the echo signal according to the simulation model established in advance, and transmit the simulated echo signal to the acoustic wave and tide measuring instrument through the signal acquisition and processing box 6.

The inside of the signal acquisition and processing box 6 is mainly two circuit boards, including a transceiver circuit board and a signal control board. The function of the transceiver circuit board is to realize the transmission and reception of four acoustic transducers, and the signal control board controls the acoustic transducers. In transmit mode or receive mode.

A detection system 8 , a control system 9 and a performance evaluation module 10 are installed in the host computer 7 . Wherein, the detection system 8 is connected with the acoustic wave and tide measuring instrument, and the detection system 8 controls the acoustic wave and tide measuring instrument to measure the wave height, wave period and wave direction in real time. The control system 9 is connected with the detection device of the present invention, and is used for controlling the start/stop of the detection device, setting detection conditions, and setting detection time. An echo simulation model is stored in the control system 9, and the model is used to set the wave height, wave period, and wave direction values of the simulated waves. The performance evaluation module 10 is used to compare the data detected by the detection system 8 with the simulated value in the control system 9 to evaluate the accuracy of the detection data of the acoustic wave and tide measuring instrument.

The laboratory detection method of the acoustic wave and tide measuring instrument of the present invention, the flow process is as shown in Figure 2, and the specific steps are as follows:

1. Test environment construction

According to Fig. 1, connect and arrange, place the detection device of the present invention above the acoustic wave and tide measuring instrument to be detected, and place the two in the test water tank 1 to ensure the transducer array of the acoustic wave and tide measuring instrument and the detection device Parts are below the water surface. The underwater host of the acoustic wave and tide measuring instrument is connected to the detection system 8 installed in the host computer 7; the transducer array of the detection device is connected to the land signal acquisition and processing box 6, and the signal acquisition and processing box 6 is installed in the host computer 7 The control system 9 is connected.

During the detection process, the acoustic transducer array 4 of the detection device is placed directly above the acoustic transducer 3 of the acoustic wave and tide measuring instrument, and the special buckle is used to ensure the fixed connection between the two, with a distance of 1cm between the two. The gap can reduce the impact of the vibration of the acoustic transducer on the received signal.

2. Detection process

Acoustic tide measuring instrument: the measurement period is 2s. Within a measurement period, the acoustic wave and tide measuring instrument first transmits a signal, and the pulse width of the transmitting signal is T0; after the signal transmission is completed, the acoustic wave and tide measuring instrument turns to receive the signal, Receive the echo signal from the water body, and realize the wave measurement function by analyzing the received signal.

Detection device: the measurement cycle is also 2s. In a measurement cycle, the detection device is first in the receiving mode to receive the transmission signal from the acoustic wave and tide measuring instrument. After receiving the signal from the acoustic wave and tide measuring instrument, the detection device is in the transmitting mode. The echo simulation model is selected according to the wave simulation model, and the echo simulation model is stored in the control system installed on the host computer, and can be set according to the simulation conditions.

When the next measurement period starts, the acoustic wave and tide measuring instrument and the detection device repeat the above receiving and transmitting process respectively, and the time sequence switching of the two is shown in Fig. 3 .

1. Acoustic tide meter transmits signal

In the detection process, the acoustic wave and tide measuring instrument first transmits signals, the transmitting signals of the four acoustic transducers of the acoustic wave and tide measuring instrument are consistent, the pulse amplitude y0 of the transmitting signal is fixed, and the pulse width of the transmitting signal is T ₀ . i=1, 2, 3, 4 represent four acoustic transducers, N represents the number of sampling points, and T ₀ represents the pulse width.

2. The detection device receives the signal

The detection device receives the emission signal of the acoustic wave and tide measuring instrument, and uses the threshold detection method to detect the wave. When it is greater than the specified threshold, the threshold is slightly smaller than the emission signal amplitude y0 of the acoustic wave and tide measuring instrument, and the threshold is set to 0.8*y0.

When the amplitude of the received signal is greater than the threshold, it is considered that the transmission signal of the acoustic tide measuring instrument has been received, and when the amplitude of the received signal is smaller than the threshold, it is considered that the transmission signal of the acoustic tide measuring instrument has been received. The detection device switches to the transmission signal mode after receiving, and the transmission signal of the detection device is set according to the echo signal model.

3. Echo signal simulation model

The detection device simulates the echo signal under real conditions, and establishes the echo model according to the simulation model. Assume that the original wave data curve is f(n), n=1, 2L N, and N represents the number of sampling points. The original wave data f(n) comes from the wave acquisition data under real conditions, which has real representative significance.

The four acoustic transducers measure wave information at four different positions in space, and the delays for waves reaching different measuring points will be different, assuming that the delays are N ₁ , N ₂ , N ₃ , N ₄ , the detection device The echoes represent four beams with B _i (n)i=1,2,3,4.

B _i (n)=f(n+N _i ), n=1,2L N.

(1) Establish a coordinate system as shown in Figure 4, the X-axis direction is from measuring point 3 to measuring point 4, and the Y-axis direction is from measuring point 1 to measuring point 2; the acoustic wave and tide instrument is equipped with a three-dimensional attitude sensor, and is placed on the test cloth When deploying the acoustic wave and tide meter, adjust the deployment attitude of the acoustic wave and tide meter so that the instrument coordinate Y axis is consistent with the north direction.

The data assumes that the wave direction is 0 degrees, and the wave delay difference between 1 and 2 is M measuring points. According to the array form of measuring points, the time delay difference between 1, 3 and 4 measuring points is M/2 measuring points ( M is an even number). The multi-point wave height measuring point array measures the wave direction, requiring that between any two measuring points, the wavelength of the measured wave is less than 1/2, and the selection of the M value needs to meet the above requirements. The corresponding echo model is as follows, as shown in Figure 5:

(2) Suppose the wave direction is 90 degrees

Assuming that the delay between measuring points 1, 2 and 4 is M, and the delay between measuring points 3 and 1 and 2 is M, the corresponding echo model is as follows, as shown in Figure 6:

(3) Suppose the wave direction is 180 degrees

Assuming that the delay between measuring points 1, 2 and 4 is M, and the delay between measuring points 3 and 1 and 2 is M, the corresponding echo model is as follows:

(4) Suppose the wave direction is 270 degrees.

Assuming that the delay between measuring points 1, 2 and 4 is M, and the delay between measuring points 3 and 1 and 2 is M, the corresponding echo model is as follows:

4. The detection device emits a signal

The emission signal of the detection instrument is a square wave signal, and the amplitude of the emission signal changes, and the amplitude needs to be set according to the simulation model. i=1,2,3,4 represent four beams, N represents the number of sampling points, T ₀ represents the pulse width;

5. The receiving signal of the acoustic wave and tide measuring instrument

The acoustic wave tide meter receives the transmitted signal from the detection device, and uses the threshold detection method to detect the wave. When it is greater than the specified threshold, it is considered that the measurement has obtained a real signal, and the wave height value is calculated. The threshold value is required to be less than the minimum value of the signal transmitted by the receiving device.

6. Calculation of wave direction spectrum

When the acoustic tide gauge is measuring the wave height fluctuations at four different locations, the cross-spectrum of the wave height values at the four different locations is first calculated, and then the direction spectrum is calculated using the cross-spectrum.

Acoustic tide meter has four transducers, and the wave height sequences collected by four beams are: η ₁ (n), η ₂ (n), η ₃ (n), η ₄ (n), n=1,2L N , N represents the number of data; in the calculation of the cross-spectrum, the data is divided into several parts, and some parts are allowed to overlap. The Welch weighted overlapping average method is used, which will make the cross-spectrum estimation more accurate.

When calculating the cross-power spectrum, first calculate the η ₁ (n), η ₂ (n), η ₃ (n), η ₄ (n), n=1, 2L N cross-correlation matrix, and then calculate the cross-correlation matrix through the cross-correlation matrix power matrix.

The cross-power spectrum of η ₁ (n), η ₂ (n) first calculates the cross-correlation R ₁₂ : E stands for mathematical expectation, * stands for conjugate:

Calculate the cross-correlation value between different measuring points, and get the cross-correlation matrix as follows:

By cross-correlation R ₁₂ , calculate the cross-power spectrum ω is the circular frequency:

ω=2πf

Calculate the cross power spectrum between different measuring points, the cross power spectrum matrix is:

The calculation method of the wave direction spectrum adopts the maximum likelihood algorithm (MLM), and the calculation is as follows:

S(f,θ) represents the wave direction spectrum. f, θ represent frequency and direction, respectively. The superscript H stands for conjugate transpose, is the cross-spectrum matrix, which represents the cross-spectrum between different measuring points 1, 2, 3, and 4, G is the transfer function matrix, and the transfer function of wave height is 1.

G = [1 1 1 1].

7. Calculation method of wave eigenvalues

In the wave calculation process, the wave characteristic value is calculated every hour. Commonly used wave characteristic values include: maximum wave height and corresponding period, 1/10 wave height and corresponding period, 1/3 wave height and corresponding period, average wave height and corresponding period, Main direction. After sampling the original wave data of each set of data, each set of data corresponds to one hour, and the eigenvalue calculation method is as follows:

The wave heights are sorted from large to small, and the wave periods are sorted accordingly.

Maximum wave height: the largest wave height after sorting.

The period corresponding to the maximum wave height: the wave period corresponding to the maximum wave height.

1/10 wave height: After the wave heights are sorted, the first 1/10 wave height is selected to calculate the average wave height.

1/10 wave cycle: After sorting the wave heights, select the cycle corresponding to the first 1/0 wave height to calculate the average wave cycle.

1/3 wave height: After sorting the wave heights, select the first 1/3 wave height to calculate the average wave height.

1/3 wave cycle: After the wave height is captured, select the cycle corresponding to the previous 1/3 wave height to calculate the average value of the wave cycle.

Average Wave Height: Calculates the average of all wave heights.

Average Wave Period: Calculates the average of all wave periods.

Main wave direction calculation method: the direction corresponding to all the maximum values in the two-dimensional direction spectrum.

8. Data analysis and evaluation

The detection device can simulate the echo signal under real conditions according to the echo simulation model. During the detection process, it can simulate multiple hours of original wave data as needed, and simulate each hour with different wave height, wave period and wave direction values.

During the detection process, the measured values of wave height, wave period and wave direction are obtained through the measurement of the acoustic wave and tide measuring instrument. Calculates the average error of measured and simulated values. A parameter measurement is considered accurate when the average error of the parameter is less than the measurement accuracy of the parameter. The measurement accuracy of each parameter is shown in Table 1.

Table 1 The main technical indicators of the acoustic wave and tide measuring instrument

Claims (7)

1. a kind of laboratory testing device suitable for acoustic wave tide measuring instrument, it is characterised in that: including test water tank, fixed branch Frame, acoustic transducer battle array, signal acquisition process case and control system, the acoustic transducer battle array are mounted on support bracket fastened top Inside；The fixed bracket is placed in test water tank；The acoustic transducer battle array is connected by cable and signal acquisition process case It connects, the signal acquisition process case is connect by data line with control system.

2. the laboratory testing device according to claim 1 suitable for acoustic wave tide measuring instrument, it is characterised in that: described Acoustic transducer battle array close the acoustic transducer set by four transmitting-receivings and form, one of acoustic transducer is centrally located, other Three equidistantly distributeds are in periphery.

3. the laboratory testing device according to claim 1 suitable for acoustic wave tide measuring instrument, it is characterised in that: described Signal acquisition process case include transmission circuit plate and signal control panel, transmission circuit plate is for realizing four transducer signals Transmitting and reception, signal control panel control the switching of acoustic transducer emission mode and reception pattern.

4. the laboratory testing device according to claim 1 suitable for acoustic wave tide measuring instrument, it is characterised in that: described Wave height, wave week of the control system for controlling detection device starting/stopping and testing conditions, detection time, in testing conditions The setting of phase, wave direction value.

5. the laboratory testing device according to claim 4 suitable for acoustic wave tide measuring instrument, it is characterised in that: described Control system include simulation model, the wave height, wave period, wave direction value in the testing conditions according to the simulation model into Row setting.

6. the laboratory testing device according to claim 5 suitable for acoustic wave tide measuring instrument, it is characterised in that: described Control system include performance evaluation module, the performance evaluation module is used for the measured value of acoustic wave tide measuring instrument and emulation Value compares, so that whether evaluate measurement data accurate.

7. a kind of laboratory testing method of acoustic wave tide measuring instrument, it is characterised in that: the following steps are included:

(1) it will test placement to be placed on above acoustic wave tide measuring instrument to be detected, the two be placed in test water tank, guarantee acoustics The acoustic transducer battle array of wave tide instrument and detection device is in the water surface or less；

(2) measurement period is 2s, and in a measurement period, acoustic wave tide measuring instrument is first in emission mode, detection device In a receive mode, acoustic wave tide measuring instrument first emits signal, and detection device receives the transmitting letter from acoustic wave tide measuring instrument Number；After detection device receives, acoustic wave tide measuring instrument switchs to reception pattern, and detection device switchs to emission mode, detection dress Interior selection echo simulation model is set, analogue echo simultaneously emits；Acoustic wave tide instrument measuring instrument receives the transmitting letter for carrying out self-test device Number, calculate real-time wave height value；The next period repeats the above process；

(3) time of measuring is accumulative often expires a hour, calculates a wave directional spectrum and wave characteristics；

(4) the calculated wave directional spectrum of acoustic wave tide measuring instrument and wave characteristics are compared with simulation model, is calculated Mean error, according to mean error compared with accuracy of measurement, whether assessment measured value of parameters is accurate.