CN101334473B - Deep water net cage fish school status remote real time monitoring instrument based on acoustic multi-beam - Google Patents

Abstract

The invention discloses an acoustic multi-beam-based remote real-time monitor of fish shoals in a deep water net cage, relating to a monitoring device. The invention provides the acoustic multi-beam-based remote real-time monitor of the fish shoals in the deep water net cage which has flexible marine operation, easy placement and strong anti-wave capability. The acoustic multi-beam-based remote real-time monitor is provided with a detection signal transmitting and echo collection device, a data analysis and image display device and a data wireless transmission device. The detection signal transmitting and echo collection device is provided with an annular transducer array and a control box, and the annular transducer array is provided with single beam transducer array elements; the control box is provided with a power supply, a controller, a detection signal generator, a power amplifier, a signal collection and preservation circuit and a signal pre-treatment circuit. The data analysis and image display device is used for realizing the remote detection and the control operations on a bank station, carrying out the analysis of the received monitoring data of the fish shoals in the net cage and carrying out the image display of the result. The data wireless transmission device is connected with the detection signal transmitting and echo collection device and the data analysis and image display device.

Description

Remote real-time monitoring instrument for fish school status in deep water cages based on hydroacoustic multi-beam

technical field

The invention relates to a monitoring device, in particular to a remote real-time monitor for the safety state of fish schools in deep water net cages based on underwater acoustic multi-beam technology.

Background technique

Usually, the existing fishing rafts cannot withstand the attack of typhoon and big waves, and there are many problems in the production of cage culture. For example, Typhoon Feiyan in 2001 disabled 210,000 seawater net cages in my country, causing a direct economic loss of 1.18 billion yuan. Deep-water cages have the characteristics of strong wind and wave resistance and high-yield and high-efficiency breeding. Currently, they are widely used in marine fish farming and have a good momentum of development. However, compared with traditional cage culture, deep-water cages are usually difficult to observe the net clothing and the activity state of fish in the cage due to the deep waters in which the cages are located and the large range of fish activities. Therefore, how to carry out real-time monitoring on the activity status of fish schools in the net cage, the size change of fish schools, etc., and how to carry out effective and timely alarm when fish schools are found to escape is a very urgent problem to be solved. A key technology in cage culture.

In my country, in addition to the relatively clear sea water in Hainan, the sea water in the southeast and most of the northern coastal areas is relatively turbid. The effective observation distance of underwater targets using optical methods is only 1-2m. In order to obtain good images, it is necessary to use a large viewing angle and A lens with high precision is expensive, and the use of optical detection also requires a large power supply system.

Abroad, there are mainly the Massachusetts Institute of Technology and Woods Hole Oceanographic Research Institute in 2002 to develop a remote cage monitoring system combining optics and acoustics. The core component of the acoustic method is the 881-000-420 digital imaging/profile sonar produced by Imagenex, which operates at frequencies of 1MHz, 675kHz and 310kHz, and the corresponding beamwidths are 1.4°, 2.4° and 4.8°; The range is 10-50m; the DC working voltage is 22-48V, the maximum current is 1A; the maximum working depth is 1000m; the whole net cage can be scanned by the rotation of the stepper motor in the horizontal and vertical axes. It is matched with the WIN881A software run by Toshiba Satellite notebook computer, which controls, displays and records data through the two-wire RS-485 serial port. Its advantage is that it is suitable for more water areas, and it can generally estimate the total amount of fish in the net cage. The disadvantage is that it needs to enter the motor to rotate and detect and scan, and the echo signal cannot distinguish a single fish; the acoustic imaging time is long, the standard imaging time of the system is 3 minutes, and the imaging time corresponding to the minimum scanning period is also greater than 1 minute, so it is not suitable for swimming in the cage. Schools of fish can generate a large number of repeated estimates, leading to large errors, and are expensive, especially because of the acoustic imaging techniques used. The control and remote data transmission part of the system is composed of CF1 microprocessor of Persistor Company and SRM6000 spread spectrum radio modem of Data-Linc Company, and three 12V storage batteries are packaged in a waterproof PVC box.

In China, the East China Sea Research Station of the Chinese Academy of Sciences, the Institute of Fishery Machinery and Instruments of the Chinese Academy of Fishery Sciences, and the Department of Oceanography of Xiamen University have all carried out research on the cage monitoring system.

In 2002, Donghai Station of the Chinese Academy of Sciences undertook the safety monitoring of net clothing in the major scientific and technological project of Zhejiang Province "Zhejiang Deep-water Cage Monitoring Equipment in Mixed Waters", and adopted a monitoring method of underwater robot inspection. The principle of this method is: install a sonar sensor on the underwater robot, and set the action route for it, so that it will patrol repeatedly according to the preset route, thus forming a warning zone. In this warning zone, if fish appear If there is any abnormal phenomenon in the activity, the robot will report to the management personnel to achieve the purpose of warning. This method is highly mobile and has certain reference value, but there are big problems in the stability of robot operation, fault repair, energy supplement, non-professional operation, remote transmission of underwater data and implementation cost.

In addition, relevant experts and researchers have also proposed a variety of different scenarios, such as: 1) Acoustic warning belts for setting points: placing a large number of large cages in a sea area to form a "farm" , and then deploy a certain number of single-beam sonars on the seabed around the "farm" to implement acoustic warnings around the cage area. The advantage of this method is that it can monitor the cage group, reduce the input cost, and it can be used for a long time as long as it is deployed once. However, there are also various problems, such as offshore power supply, data transmission and cable laying. Due to the fixed-point installation, the impact of strong winds and waves must also be considered, and there is still a lag in monitoring, especially for the cages in the center of the monitoring belt. Once the netting breaks, the system cannot immediately detect the information and issue an alarm. 2) Vertical detection method: place the transducer on the sea surface inside the cage, and detect the situation of fish schools vertically to the inside of the cage (and the bottom of the sea). The transducer of this method adopts a vertical detection method, which is convenient to realize. However, it is impossible to monitor the condition of the nets around the cage, and the echo signal of the fish school at the bottom of the cage is easily affected by the reverberation of the seabed.

Contents of the invention

The object of the present invention is to provide a remote real-time monitoring instrument for deep-water net cage fish state based on hydroacoustic multi-beams, which is smart to operate at sea, easy to install, and strong in wind and wave resistance.

The technical solution of the invention is a multi-beam annular transducer array composed of several single-beam transducers, which is used for remote, real-time and all-round monitoring of the safety status of fish schools in deep-water net cages. The multi-beam annular transducer array is fixed in the center of the net cage, so that it can detect the whole net cage in the horizontal direction (and the vertical direction in a certain range, which can be flexibly adjusted by the connecting rod). The multi-beam acoustic method is used to detect underwater fish schools, which can realize remote, real-time and all-round monitoring of the distribution and activity status of fish schools in deep-water cage culture. When an abnormal situation is found, the monitoring system can automatically send out an alarm signal .

The invention is provided with a detection signal emission and echo acquisition device, a data analysis and image display device and a data wireless transmission device.

The detection signal transmission and echo collection device is arranged at the deep-water cage culture site. The detection signal transmission and echo collection device is equipped with a ring transducer array and a control box. The ring transducer array is equipped with at least 2 single-beam transducers The array element; the control box is equipped with a power supply, a controller, a detection signal generator, a power amplifier, a signal acquisition and storage circuit, and at least two signal preprocessing circuits; the input end of the detection signal generator is connected to the output end of the controller, and the detection The signal generator generates a periodic high-frequency narrow pulse signal for fish detection. The output terminal of the detection signal generator is connected to the input terminal of the power amplifier, and the output terminal of the power amplifier is connected to the input terminal of each array element of the ring transducer array. The output terminals of each array element of the array transmit detection signals to the deep water cage; the output terminal of the controller’s working start signal is connected to the control terminal of the analog-to-digital converter and the data memory in the acquisition and storage circuit; the input terminal of the preamplifier is connected to the ring The output terminals of each array element in the transducer array.

Data analysis and image display devices are placed on the shore station. The data analysis and image display device is used to realize remote detection and control operation on the shore station, analyze the received fish state monitoring data in the net cage, and display the image of the result.

The data wireless transmission device is respectively connected to the detection signal emission and echo collection device on the deep-water net cage and the data analysis and image display device on the shore station. The data wireless transmission device sends the fish school echo signal detected in the deep water cage to the data analysis and image display device on the shore station through the wireless transmission device.

The annular transducer array is preferably arranged at 2 to 3 m underwater in the center of the deep-water net cage, and the control box is preferably arranged at any place on the water surface of the deep-water net cage. The horizontal detection angle and vertical detection angle of each single-beam transducer array element in the annular transducer array are preferably equal, and the value depends on the number N of single-beam transducer array elements and the size of the cage. Certainly. The horizontal detection angle is equal to 360° divided by the number N, so that the horizontal detection range of the annular transducer array just covers the horizontal 360° full direction of the deep-water cage; the vertical detection angle is determined by the depth h and radius r of the cage, and according to the formula 2arctan (h/2r) is roughly determined, so that the vertical detection range of the annular transducer array can cover the activity space of the fish school in the vertical direction of the net cage. The more the number of single-beam transducer elements in the annular transducer array, the higher the detection accuracy, but it also makes the detection system more complicated. The number of preamplifiers, band-pass filters and detection circuits in the signal preprocessing circuit corresponds to the number of array elements in the ring transducer array.

The detection signal generator is best to use a high-frequency narrow pulse signal generator. The repetition period is determined by the detection distance and the working rate of the analog-to-digital converter and memory. The longer the detection distance, the slower the working rate and the longer the required repetition period. . Generally set at tens to hundreds of milliseconds; the pulse width is mainly determined by the size of the individual fish, the individual is large, the pulse width can be set wider, generally set to hundreds of microseconds; the higher the carrier frequency, the better it is to resist the low-frequency noise of the ocean background Interference and suppression of reverberation, but depends on factors such as sound transmission loss, generally choose tens to hundreds of kilohertz.

The power supply is preferably a battery. The power amplifier can be a class D push-pull power amplifier coupled with a transformer.

The signal preprocessing circuit is provided with a preamplifier, a bandpass filter and a detection circuit. The input end of the band-pass filter is connected to the output end of the preamplifier, and the input end of the detection circuit is connected to the output end of the band-pass filter. The signal acquisition and storage circuit is provided with an analog-to-digital converter (ADC) and a data memory.

The data wireless transmission device can adopt a pair of serial port wireless communication modules. The serial port wireless communication module can adopt the serial port wireless communication module of FSK modulation mode, and the carrier frequency can be 420-450.3MHz.

Because the present invention adopts multi-beam emission and multi-channel reception parallel signal processing mode, the time required for scanning omni-directional cage imaging is greatly shortened, and real-time omni-directional monitoring is really achieved. The imaging time for the present invention to complete one cage scan is about 40s. If the data transmission rate of the wireless communication module is increased, the imaging time can be further reduced to increase the detection speed. The improvement of the detection speed can obtain more detailed time distribution information of fish schools, which is beneficial to obtain the distribution status of fish schools and improve the estimation accuracy of fish schools in the dynamic environment of fish swimming in deep water cages.

Because the present invention adopts the multi-beam omni-directional detection mode of the annular transducer array, it has the advantages of electro-acoustic detection, and avoids the disadvantages of inconvenient operation and easy failure of mechanical rotation scanning at sea. The system avoids the use of stepping motors required for detecting different orientations and the water working platform on which the stepping motors are placed, which not only simplifies the system equipment, but also greatly reduces the energy consumption of the system. At the same time, the standby time is extended, and the inconvenience caused by frequent loading and unloading of the system due to insufficient power is alleviated.

The sea experiment shows that the present invention is dexterous in sea operation, easy to install and strong in wind and wave resistance.

Description of drawings

Fig. 1 is a layout diagram of an annular transducer array, a connecting rod, a control box and a data wireless transmission device and a schematic diagram of detection of a single transducer array element according to an embodiment of the present invention.

Fig. 2 is an overall composition block diagram of a remote real-time monitoring instrument for fish school status in deep-water cages based on hydroacoustic multi-beam according to an embodiment of the present invention.

Fig. 3 is the internal structure diagram of each block diagram (dotted line frame part) of the composition block diagram of the remote real-time monitor of fish school status in deep-water cage based on underwater acoustic multi-beam according to the embodiment of the present invention.

FIG. 4 is a schematic diagram of circuit composition of a fourth-order bandpass filter composed of two second-order sections cascaded in an embodiment of the present invention.

Fig. 5 is a simulation curve diagram of amplitude frequency and phase frequency of the filter according to the embodiment of the present invention. In Fig. 5, a represents the magnitude-frequency curve of the band-pass filter, and b represents the phase-frequency curve of the band-pass filter. The abscissa is frequency (kHz), and the ordinate is amplitude (decibel) and angle (degrees).

FIG. 6 is a control flowchart of the controller and the signal acquisition and storage circuit of the embodiment of the present invention.

Detailed ways

The following embodiments will further illustrate the present invention in conjunction with the accompanying drawings.

Referring to Figures 1 and 2, the present invention includes a detection signal emission and echo acquisition device arranged on a deep-water cage culture site, a data analysis and image display device located on a land shore station, and a data wireless transmission device connecting the two.

The detection signal emission and echo collection device is set at the offshore cage culture site, and the detection signal emission and echo collection device is composed of a ring transducer array 1 and a control box 2 . The annular transducer array is set at 2-3m underwater in the center of the deep-water cage, and the control box is set on the water surface of the cage (as shown in Figure 1, the other codes in the figure are 3. Connecting rod, 4. Data wireless transmission device ).

Fig. 2 shows the overall composition block diagram of the remote real-time monitoring instrument for fish school status in deep water cages based on hydroacoustic multi-beam according to the embodiment of the present invention. In Fig. 2, comprise the annular transducer array 1, the control box 2, the connecting rod 3 that are arranged on the offshore net cage culture site (dashed line frame part); The data analysis and the image display device 5 that are arranged on the shore station; Connect the data wireless transmission device 4 on the sea and the shore station.

The connection mode of the remote real-time monitor of fish school status in deep-water cages based on underwater acoustic multi-beam is: the input end (or output end) of the control box 2 is connected to the output end (or input end) of the data wireless transmission device 4, and the control box 2 The output end (or input end) of the connecting rod 3 is connected to the annular transducer array 1, and the input end (or output end) of the data wireless transmission device 4 is connected to the output end (or output end) of the data analysis and image display device 5 input terminal).

Fig. 3 shows the internal structure of each block diagram of the remote real-time monitor of fish school status in deep-water cages based on hydroacoustic multi-beam according to the embodiment of the present invention (dotted line frame part). Control box 2 among Fig. 3 (see dotted box 2) has included controller 21, detection signal generator 22, power amplifier 23, preamplifier 24, band-pass filter 25, detection circuit 26, electronic switch 27, modulus Converter 28 , first-in-first-out mode data memory 29 , system power supply 210 . Wherein, preamplifier 24 is made up of 8 sub-preamplifiers, is respectively preamplifier 241, preamplifier 242, ..., preamplifier 247, preamplifier 248; Band-pass filter 25 is also made up of 8 sub-bandpasses Filter is formed, is respectively band-pass filter 251, band-pass filter 252, ..., band-pass filter 257, band-pass filter 258; Detection circuit 26 is made up of 8 sub-detection circuits, is respectively detection circuit 261, detection circuit Circuit 262, . . . , detection circuit 267, detection circuit 268. The data wireless transmission device 4 among Fig. 3 (see dotted line box 4) has included the serial port wireless communication module 41 that is arranged on the net box, the serial port wireless communication module 42 on the shore station. Data analysis and image display device 5 among Fig. 3 (see dotted line frame 5) has included system starting signal module 51, data reception processing module 52, image display, fish amount estimation and early warning module 53.

In the following, combined with Figure 3, the implementation process and working principle of the remote real-time monitoring instrument for fish school status in deep water cages based on hydroacoustic multi-beam are introduced.

The detection signal transmission connection mode is: the input end of the controller 21 in the control box 2 is connected to the output end of the serial port wireless communication module 41 arranged on the net box in the data wireless transmission device 4, and the input end of the serial port wireless communication module 41 receives From the system start signal sent by the output of the serial port wireless communication module 42 on the shore station, the input end of the serial port communication module 42 on the shore station is connected to the output end of the system start signal module 51 in the data analysis and image display device 5 . The output end of the controller 21 is connected to the input end of the detection signal generator 22, the output end of the detection signal generator 22 is connected to the input end of the power amplifier 23, and the output end of the power amplifier 23 is connected to the input end of the ring transducer 1 , and finally the output end of the annular transducer 1 radiates sound waves to detect targets in the cage water.

The wiring mode of the echo acquisition device is: the output end of the ring transducer array 1 (set as 8 single-beam transducer array elements, with 8 sub-output ends) is connected to the input end of the preamplifier 24 through the connecting rod 3 (8 roads, 8 sub-input terminals are arranged), the output terminal of preamplifier 24 (8 sub-output terminals are arranged) is connected to the input terminal of band-pass filter 25 (8 sub-input terminals are arranged), the output terminal of filter 25 ( There are 8 sub-outputs) connected to the input of the detection circuit 26 (8 sub-inputs), the output of the detection circuit 26 (8 sub-outputs) is connected to the input of the electronic switch 27, the output of the electronic switch 27 Be connected to the input end of analog-to-digital converter 28, the output end of analog-to-digital converter 28 is connected to the input end of FIFO mode memory 29, the output end of FIFO mode memory 29 is connected to the serial port communication module 41 on the net box In addition, the output end of the control controller 21 is also connected to the control end of the electronic switch 27, the analog-to-digital converter 28, and the first-in-first-out mode data memory 29 at the same time. The output end of the serial port wireless communication module 41 on the net cage sends the echo data detected to the input end of the serial port wireless communication module 42 on the shore station after wireless transmission, and the output end of the serial port communication module 42 on the shore station is connected to The input end of the data reception processing module 52, the output end of the data reception processing module 52 is connected to the input end of the image display, fish school estimation, and early warning module 53.

The working process of the system: A. First, the controller 21 receives the system start signal from the system start signal module 51 on the remote shore station through the data wireless transmission device 4, and the controller 21 starts the system; B. Then the controller 21 controls Detection signal generator 22 produces the periodical high-frequency narrow pulse signal that detects school of fish usefulness, after being amplified by power amplifier 23, it is emitted in all directions in the net cage by annular transducer array 1; C, then controller 21 to electronic switch 27 , analog-to-digital converter 28, first-in-first-out mode data memory 29 send a work start signal, notify the analog-to-digital converter (ADC) to receive by transducer array 1, through preamplifier 24, bandpass filter 25 and The detection circuit 26 samples the echo signals that have undergone signal preprocessing, and stores the sampled data in sequence in the data memory 29 in the first-in-first-out mode, and waits for the controller 21 to send out data transmission control instructions, and sequentially detects The data is sent through the serial port wireless communication module 41 on the net box in the data wireless transmission device 4; D, treat that data collection and sending all finish, after completing a complete detection process, except controller 21 enters standby state in the control box 2, Waiting for the system startup order of the shore station, other parts stop working, reduce power consumption; After the input data receiving and processing module 52 conducts data analysis, it is output to the image display, fish school estimation, and early warning module 53 to display the monitoring results.

1. Detection signal emission and echo acquisition device

1. Ring transducer array

The present invention is characterized in that it adopts the multi-beam detection mode of the annular transducer array, and can detect the omnidirectional distribution of fish schools in the entire net cage without rotating the transducer. The annular transducer array consists of several single-beam transducer array elements with the same horizontal detection angle and the same vertical detection angle arranged in a ring structure. Under this structure, each transducer array element is responsible for the detection of a specific area in the cage. The more transducer elements in the array, the finer the division of each transducer's detection area, and the better the echo signal can reflect the spatial distribution characteristics of fish in the cage; multiple transducer elements The echo signal within a certain period of time can reflect the time and space distribution characteristics of the fish in the cage. Compared with the traditional single-beam transducer rotation scanning method, this array detection method can not only reduce the mechanical rotating parts such as motors required for omni-directional scanning, make the operation on the sea site simple and convenient, but also greatly improve the Spatial resolution of fish schools in cages and estimation accuracy of fish schools. However, as the number of transducers increases, the implementation of the monitoring system will become more complex. This embodiment adopts the annular transducer array that 8 single-beam transducer array elements form, and the horizontal direction detection angle of design each transducer array element is 45 °, and the vertical direction detection angle is 60 °, can make like this The detection area of the monitoring system basically covers the fish activity space in the deep-water net cage (in this embodiment, the size of the deep-water net cage selected for the offshore field experiment is that the diameter D is 12m, and the height h is 6m, as shown in Figure 1) .

2. Control box

The control box integrates the system power supply, controller (composed of two AT89S52 single-chip microcomputers and some peripheral circuits), detection signal generator, power amplifier, signal acquisition and storage circuit and 8-channel signal preprocessing circuit (corresponding to the ring transducer The number of array elements) is the core part of the system. It is airtightly packaged by a waterproof box and installed at any position of the net cage on the water surface, which is convenient for fishermen to load and unload.

1) Power supply

For the deep-water cage monitoring system deployed offshore, battery power is generally used, so how to reduce the power consumption of the system and ensure the continuous operation of the system for a long time is an important issue. The power supply of the system is composed of two 12V ordinary battery car batteries connected in series to provide the ±12V DC voltage required for the system to work. The system can work for more than 3 days when the system continues to receive startup instructions, and the system can work for more than 3 days. If the intermittent work mode is used and the system is only started to work within a specific time, the power supply working time can be extended to half a month or even longer.

2) Detection signal generator

The detection signal generator is controlled by the controller to generate periodic high-frequency pulse detection signals. The design of the detection signal depends on factors such as the distribution of environmental noise (determining the carrier frequency), the average size of the fish in the detection cage (determining the pulse width), and the overall processing speed of the system (determining the repetition period). Pulse signal. The high-frequency carrier is beneficial to resist the low-frequency noise interference of the ocean background and improve the resolution of the fish body. The detection signal of the present invention adopts a pulse signal with a pulse width of 100 μs, a carrier wave of 50 kHz, and a repetition period of 100 ms.

3) Power amplifier

The system uses a transformer-coupled class D push-pull power amplifier, and the output power of the designed system is about 50W. The fish detection signal is sent in the form of pulses, and its maximum instantaneous output power can reach 100W, so it is enough to ensure that the echo has a large signal-to-noise ratio for fish detection in a limited space in and around the cage.

4) 8-channel signal preprocessing circuit

The 8-channel signal preprocessing circuit corresponds to processing the echo signals received by the 8 array elements in the annular transducer array, and each signal preprocessing circuit is provided with a preamplifier, a band-pass filter and a detection circuit.

a) The preamplifier adopts the system programming analog device ispPAC10 of Lattice Company, which is composed of 4 identical basic unit circuits - signal processing block (PAC block). Each PAC block is composed of two instrumentation amplifiers and an output amplifier, together with resistors and capacitors to form a basic amplifying unit with differential input and differential output; PAC blocks can be cascaded to form a multi-stage amplifying circuit, and these 4 PAC blocks are cascaded It can be configured as various gains between -160000 and 160000 times. A piece of ispPAC10 is used to form two channels of preamplifiers, and the amplification gain of each channel can be adjusted between -400 and 400 according to the needs of the site.

b) The band-pass filter adopts the MAX274 single-chip integrated active filter chip of MAXIM Company, which contains 4 second-order variable filter units (second-order sections), no external capacitors are needed, and only external resistors are needed to realize 8th order bandpass filter operating up to 150kHz. According to the needs of the actual system, each piece of MAX274 is designed as two fourth-order Butterworth bandpass filters with a center frequency of 50kHz and a bandwidth of 4kHz. Through the design software of the MAX274 filter, the external resistance value of the filter can be easily calculated. Figure 4 shows the schematic diagram of the circuit composition of a fourth-order bandpass filter composed of two second-order sections cascaded. Each second-order section can adjust the center of the filter through the values of external resistors R1, R2, R3, and R4. Parameters such as frequency, Q value, and passband width; LPO and BPO represent the output terminals of low-pass filter and band-pass filter.

Figure 5 shows the simulation curve of the designed filter transmission characteristics. Table 1 gives the design parameters of the two second-order sections that make up the filter.

Table 1

Second stage section F ₀ (kHz) Q R ₁ (kΩ) R ₂ (kΩ) R ₃ (kΩ) R ₄ (kΩ) 1 47.247 8.853 52.913 42.331 74.95 37.331 2 52.913 8.853 47.247 37.398 66.925 32.798

c), the present embodiment adopts the energy detection method to determine the size of the fish school. In the design, a detection circuit is added after the band-pass filter to extract the amplitude information of the echo signal. Since the signal sampled by the analog-to-digital converter A/D is the detected envelope signal instead of the carrier signal, the required sampling frequency of the analog-to-digital converter A/D is greatly reduced, which reduces the time required by the data wireless transmission device. The amount of data that needs to be transmitted enables the system to be remotely monitored in real time.

5) Signal acquisition and storage circuit

The signal acquisition and storage circuit is composed of an analog-to-digital converter (ADC0820BCN) and a first-in-first-out data memory (IDT7208), and its work is controlled by the controller. The controller controls the electronic switch to select the output of a signal preprocessing circuit to connect to the analog-to-digital converter. After the analog-to-digital conversion is completed, the data is stored in the data memory and waits for the sending signal from the controller, so as to send the data to the shore station.

The minimum configurable sampling time of the analog-to-digital converter ADC0820BCN is 1.5μs, that is, the sampling rate is as high as 660kHz, which can fully satisfy the envelope signal sampling. In this embodiment, the sampling rate is configured by a control signal sent by the controller, and is set to 10kHz. As shown in Figure 1, the transducer is arranged in the detection mode at the center of the net cage. As long as the detection distance is greater than 6m, the entire net cage can be covered. In this embodiment, the detection distance is designed to be 9m. According to the sampling rate conversion, the number of sampling points corresponding to the distance is 120 points.

The first-in-first-out mode data memory IDT7208 has a 64K data buffer area, an independent read and write port and an independent read and write control clock, and can read and write data at the same time. When the controller sends a write clock signal to the first-in-first-out mode data memory, the memory writes the output data of the analog-to-digital converter into the buffer area in sequence through the write port; when the controller sends a read clock signal to the memory, the memory passes the read port The output port reads out the data stored in the buffer in turn, and sends them to the shore station through the data wireless transmission device.

6) Controller

The controller is composed of two AT89S52 single-chip microcomputers and some peripheral circuits, and is the logic control center of the whole system. Its control flow is shown in Figure 6. No. 1 MCU controls command reception and data transmission. Its working process is: (1) Initialize, set system parameters such as communication baud rate (9600bps), and enter the system start command waiting state; (2) After receiving the system start command sent by the shore station through the wireless data sending device, send to No. 2 MCU sends sampling instruction; (3) enters 10ms delay, and waits for the sampling data to be saved in the first-in-first-out mode data memory (FIFO); (4) reads the data in the first-in-first-out mode data memory (FIFO), and appends After identifying information such as channel number and frame mark, send the data back to the shore station; (5) check whether the first-in-first-out mode data memory (FIFO) is empty, and if it is not empty, continue to step (4), otherwise further check No. 2 Whether the sampling controlled by the single-chip microcomputer is over; (6) If it is not over, it means that the sampling is still continuing, and the data in the first-in-first-out mode data memory (FIFO) is only sent temporarily, and the program jumps back to the state of (3). If the sampling is over, it means that the detection is completed. After sending a feedback signal to the shore station, it enters the waiting state for the next detection start command. No. 2 MCU controls data acquisition, and its workflow is as follows: (1) Initialize, set system parameters such as sampling rate (10kHz), detection distance, number of echoes collected by each channel, and enter the waiting state for sampling instructions; (2) Receive No. 1 MCU (3) Start the detection signal generator to send a pulse detection signal; (4) The controller controls the electronic switch to sample the pre-processed echo signals of the 8 channels in turn within 100μs to realize the "8-channel Parallel" 10k sampling rate, repeated sampling 120 times to complete the echo collection of a certain detection signal; (5) Repeat step (3) according to the set number of times to complete the data collection of the entire detection process; (6) Feedback to No. 1 single-chip microcomputer After the sampling end signal, enter the waiting state of the sampling instruction.

2. Data wireless transmission device

The data wireless transmission device is composed of a pair of serial port wireless communication modules. A pair of SRWF-501-50 serial port wireless modules from Shanghai Sangrui Electronic Technology Co., Ltd. are used in the system. The module adopts FSK modulation mode; the selected carrier frequency is 420-450.3MHz (divided into 8 frequency bands, the user can choose a channel with weak interference according to the distribution characteristics of the environmental noise on site to reduce the transmission bit error rate); UART TTL/RS-232/RS-485 three interface types to meet the needs of different situations, the interface rate is 9600bps; the transmission power is 50mW; the reliable transmission distance is 1200m in open space environment conditions; the working temperature is -25 ~ 80 ℃; working humidity is 10% to 90% relative humidity; external dimensions are 47mm×26mm×10mm. At the end of the detection signal transmission and echo acquisition device at sea, the module uses a UART TTL interface to connect to the UART port of the No. 1 microcontroller in the controller to receive the user's system detection start command and send sampling data; data analysis and image display at the shore station On the device side, the module uses the RS-232 interface to connect to the PC serial port to send the system start signal for system detection and receive sampling data.

3. Data analysis and image display device

The data analysis and image display device for the start of the control system and the monitoring results of the activity status of the cage fish are located on the remote shore. The supporting user monitoring program of the system is developed based on the Laboratory Virtual Instrument Engineering Workbench (LabVIEW for short) of National Instruments. LabVIEW is widely used in data acquisition, instrument control, process monitoring and automatic testing in the field of laboratory research and industrial control automation. It uses a large number of knobs, switches, waveform diagrams, etc. to make the interface intuitive and vivid.

The program is mainly divided into 5 functions: one is the data collection part, its function is to receive the detected data sent by the serial port communication module 41 on the net box through the shore station serial communication module 42 installed on the PC; the other is data processing The third is the image processing program, which displays the processed data in the form of a radar chart; the fourth is the image saving program; the fifth is the fish quantity estimation and alarm program , if the estimated fish quantity decreases to 75% of the original normal fish quantity estimate or if any abnormal situation occurs during the monitoring process, an alarm signal will be sent.

Program at first sends start-up instruction (command is made of a string of hexadecimal numbers to the controller 21 of net cage site by data wireless transmission device 4, and its form can be set freely by the user, adopts 6 hexadecimal numbers in the present embodiment Such as the command form of FAFAFA); then the program enters the serial port query state, once it finds that there is received data in the serial port buffer, it will save the data in the file specified by the program in turn; at the same time, the program will identify the channel of the received data, Perform necessary digital signal processing according to the set operation parameters, such as time gain compensation, digital filtering, reverberation suppression, etc.; then display the processed data as an image; after receiving the data sent back from the sending end, according to the echo The energy integral method estimates the fish school echo quantity in the cage, if the detected fish school quantity value and the estimated value difference of the normal fish quantity of original setting reach a certain degree (this embodiment is set as 25%), the system will An alert message will be sent to the user indicating a possible escape of fish in the cage.

The data imaging principle of the present invention is based on the fish shoal distribution state diagram in the simulated net cage of the radar map, and the radar map is divided into 8 display areas on average according to the number of transducers in the annular transducer array, and each display area is divided into 8 display areas respectively. corresponds to a transducer. Each group of data received back is displayed in the corresponding radar map partition according to the determined respective channel numbers, and each partition reflects the spatial distribution information of fish schools in the cage; and each group of data with the same channel number is sequentially received according to the receiving order Displayed in the same partition, reflecting the time distribution information of fish swimming. Spatial distribution information not only reflects the spatial distribution of fish schools, but also reflects the damage of nets; and time distribution information reflects the movement of fish schools, so that the amount of fish schools in the cage can be estimated more accurately.

Claims (4)

1. A remote real-time monitoring instrument for fish schools in deep water cages based on hydroacoustic multi-beam, characterized in that it is equipped with a detection signal emission and echo collection device, a data analysis and image display device and a data wireless transmission device; The detection signal transmission and echo collection device is arranged at the deep-water cage culture site. The detection signal transmission and echo collection device is equipped with a ring transducer array and a control box. The ring transducer array is equipped with at least 2 single-beam transducers The array element, the control box is equipped with a power supply, a controller, a detection signal generator, a power amplifier, a signal acquisition and storage circuit, and at least two signal preprocessing circuits. The input end of the detection signal generator is connected to the output end of the controller, and the detection The signal generator generates a periodic high-frequency narrow pulse signal for fish detection. The output terminal of the detection signal generator is connected to the input terminal of the power amplifier, and the output terminal of the power amplifier is connected to the input terminal of each array element of the ring transducer array. The output terminals of each array element of the array transmit detection signals to the deep water cage, the output terminal of the controller’s working start signal is connected to the control terminal of the analog-to-digital converter and the data storage in the acquisition and storage circuit, and the input terminal of the preamplifier is connected to the ring The output ends of each array element in the transducer array, the annular transducer array is set at 2-3m underwater in the center of the deep-water net cage, the detection signal generator is a high-frequency narrow pulse signal generator, and the power amplifier It is a class D push-pull power amplifier coupled with a transformer, the signal preprocessing circuit is provided with a preamplifier, a bandpass filter and a detection circuit, the input terminal of the bandpass filter is connected to the output terminal of the preamplifier, and the input terminal of the detection circuit connected to the output of the bandpass filter; The data analysis and image display device is placed on the shore station, and the data analysis and image display device is used to realize remote detection and control operations on the shore station and analyze the received fish state monitoring data in the net cage and display the image of the result; The data wireless transmission device is respectively connected to the detection signal emission and echo collection device on the deep-water net cage and the data analysis and image display device on the shore station. The data wireless transmission device transmits the fish echo signals detected in the deep-water net cage In the data analysis and image display device sent to the shore station through the wireless transmission device, the data wireless transmission device is a pair of serial port wireless communication modules, and the serial port wireless module is a serial port wireless module of FSK modulation mode, and the carrier frequency is 420 ~450.3MHz. 2. The remote real-time monitoring instrument for the state of fish schools in deep-water net cages based on underwater acoustic multi-beam as claimed in claim 1, wherein the control box is arranged on the water surface of the deep-water net cages. 3. the remote real-time monitor of fish school state in deep-water cages based on underwater acoustic multi-beam as claimed in claim 1, is characterized in that the horizontal detection angle of each single-beam transducer in the annular transducer array is equal, and the vertical detection The angles are equal. 4. The remote real-time monitoring instrument for the state of fish schools in deep-water cages based on underwater acoustic multi-beams as claimed in claim 1, wherein the power supply is a battery.

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