A multi-channel system with single transmitter and multiple receivers and its layout control method based on river acoustic tomography flow measurement

Abstract

The present invention discloses a multi-channel system and layout control method for single-transmitter and multiple-receiver based on river acoustic tomography flow measurement. The method includes the following steps: (1) using a transmitting transducer and a receiving transducer with independent functions, forming a plurality of receiving transducers into a row vertically downward and arranging them at a certain interval; (2) adjusting the receiving gain of the pre-amplifier to improve the transmission quality of the received signal; (3) adjusting the layout spacing of each vertically arranged receiving transducer according to the change of water sound velocity at different temperatures, and the distance between adjacent receiving transducers is such that the water temperature difference is more than 1°C; (4) after a row of vertical receiving transducers receives the sound wave, the abnormal signal is deleted, and the average signal arrival time is calculated as the actual measurement signal arrival time based on the weight ratio of the remaining signals. The present invention solves the problem that the existing river acoustic tomography flow measurement system is affected by the change of the sound velocity of the water environment, reduces interference, and improves the quality of the received sound wave signal and the measurement stability.

Description

Technical Field

[0001] The present invention relates to the field of intelligent analysis of river flow measurement data, and in particular to a single-transmitter-multiple-receiver multi-channel system and a layout control method based on river acoustic tomography flow measurement. Background Art

[0002] River acoustic tomography offers advantages such as real-time performance, simplicity, and high resolution. By transmitting acoustic signals and analyzing the river environment information carried in the received signals, it can inversely measure flow velocity and volume over a wide area. Existing systems often use transducers with integrated transmitters and receivers to transmit signals to the opposite bank. While this technology facilitates transducer deployment and ensures high signal consistency, it places high demands on the transducer's transmit and receive performance. With current technology, achieving consistent transmit and receive performance across these transducers is difficult.

[0003] Currently, to ensure the real-time performance and simplicity of river acoustic tomography flow measurement systems, their circuit drivers are typically single-channel, and the transducers are omnidirectional, integrated transmitters and receivers. These transducers are placed horizontally at intervals, rather than vertically spaced according to depth, which can lead to signal interference. Furthermore, because the speed of sound in water is significantly affected by factors such as temperature, impurities, and water pressure, and the significant seasonal temperature differences and deep rivers in northern China, significant changes in water speed can alter the path of the sound wave, preventing the signal from reaching the receiving transducer on the other side. Therefore, in river sections with complex water conditions, it is extremely difficult for a single transducer receiver system to achieve optimal transmission and reception. Furthermore, due to temperature fluctuations caused by the alternation of day and night, the quality of transducer reception varies regularly from day to night.

[0004] Prior art systems that use acoustic wave probes to measure water flow do not employ a vertical string of receiving transducers to receive transmitted sound waves. The patent, titled "A Water Flow Detection System Based on Acoustic Tomography Section Detection," has application number CN202410695337.2. The acoustic wave probes employed with transceiver functionality receive reflected signals through a data processing unit, preprocess the reflected signals to obtain a preprocessed signal, evaluate the quality of the preprocessed signal to obtain an evaluation result, and dynamically adjust acoustic wave signal processing parameters based on the evaluation result to obtain a final preprocessed signal. Pure and noise signals are extracted from the preprocessed signal, and the variance of the noise signal is calculated. All samples of the noise signal are traversed, and the difference between adjacent samples is calculated to calculate the flow velocity distribution and flow rate. Extracting pure and noise signals in this system and method is extremely difficult. The transceiver probes employed in the system are conventionally arranged at regular lateral intervals, failing to consider the effects of water depth and temperature on sound velocity, which ultimately affects the calculation of the actual arrival time of the sound waves. Summary of the Invention

[0005] In order to solve the problem that the existing river acoustic tomography flow measurement system is affected by the change of environmental sound velocity in the water, reduce interference, and improve the quality of received sound wave signals and measurement stability, the present invention provides a single-transmitter-multiple-receiver multi-channel system based on river acoustic tomography flow measurement and a layout control method.

[0006] First, the present invention provides a multi-channel system deployment control method for single-transmitter-multi-receiver based on river acoustic tomography flow measurement, comprising the following steps:

[0007] (1) Using independent transmitting and receiving transducers, multiple receiving transducers are arranged vertically downward in a row with a certain spacing. To cope with the change of water sound velocity, each receiving transducer performs single-channel frequency impedance matching to ensure matching in receiving sensitivity.

[0008] (2) adjusting the receiving gain of the pre-amplifier to improve the quality of the received signal transmission, and adjusting the amplification gain of the pre-amplifier according to the receiving sensitivity of each receiving transducer at the operating frequency;

[0009] (3) In terms of the layout of the receiving transducers, according to the change of water sound velocity at different temperatures, the layout spacing of each vertically arranged receiving transducer is adjusted, and the distance between adjacent receiving transducers is such that the water temperature difference is more than 1°C;

[0010] (4) After a row of vertical receiving transducers receives the sound waves transmitted by the transmitting transducer on the opposite side of the river, abnormal signals are eliminated and the average signal arrival time is calculated according to the weight ratio of the remaining signals as the actual measurement signal arrival time.

[0011] Furthermore, step (2) specifically includes:

[0012] Adjusting the receiving gain of the pre-amplifier improves the transmission quality of the received signal, and adjusting the amplification gain of the pre-stage according to the receiving sensitivity of each receiving transducer at the operating frequency, so that each receiving transducer can have a unified electrical signal on the electrical signal collected by the system AD after amplification.

[0013] Further, step (3) specifically includes,

[0014] The transmitting transducer and the receiving transducer are arranged on the same side of the river channel, and the distance between the transmitting transducer and the nearest receiving transducer is kept at more than 2 times the wavelength;

[0015] Multiple receiving transducers are arranged on the same side of the river channel to collect the water temperature at the location of the vertically arranged transducers. According to the change of water sound velocity at different temperatures and the corresponding data table of water sound velocity and temperature, the layout spacing of each vertically arranged receiving transducer is calculated and adjusted. The distance between adjacent receiving transducers is such that the water temperature difference is more than 1°C.

[0016] Furthermore, step (4) specifically includes:

[0017] After receiving the sound waves from the transmitting transducer on the opposite side of the river, a row of vertical receiving transducers filters out abnormal signals, calculates the signal-to-noise ratio of the received signal of each receiving transducer, and obtains the weight ratio of each received signal;

[0018] Then, based on the weight ratio of each received signal, the average signal arrival time is calculated as the actual measured signal arrival time.

[0019] Specifically, a plurality of the receiving transducers in a vertical column use the same cable to transmit the received signal to the system host. The cable signal transmission includes power supply, ground line, and multiple signal lines, and separate frequency impedance matching is performed on the multiple signal lines.

[0020] Secondly, the present invention also provides a multi-channel system for single-transmitter, multi-receiver flow measurement based on river acoustic tomography, comprising a main unit, multiple transmitting transducers and receiving transducers with independent functions; the multiple receiving transducers are arranged vertically downward in a row and at a certain interval; in response to changes in water sound velocity, each receiving transducer performs single-channel frequency impedance matching to maintain matching in receiving sensitivity; the spacing of each vertically arranged receiving transducer is adjusted according to changes in water sound velocity at different temperatures, and the distance between adjacent receiving transducers is separated to ensure that the water temperature difference is at least 1°C;

[0021] A vertical row of multiple receiving transducers receives the sound waves from the sending transducer on the opposite side of the river and transmits them to the host. The host is used to eliminate abnormal signals and calculate the average signal arrival time as the actual measurement signal arrival time based on the weight ratio of the remaining signals.

[0022] Furthermore, the host is also used to adjust the receiving gain of the pre-stage amplifier to improve the transmission quality of the received signal, and adjust the amplification gain of the pre-stage according to the receiving sensitivity of each receiving transducer at the operating frequency.

[0023] Furthermore, the transmitting transducer and the receiving transducer arranged on the same side of the river channel are kept at a distance of more than 2 times the wavelength from the nearest receiving transducer; the system also includes a temperature detector for collecting the water temperature at the position of the vertically arranged transducers arranged on the same side of the river channel; the host calculates and adjusts the layout spacing of each vertically arranged receiving transducer according to the change of the sound velocity of the water body at different temperatures and with reference to the corresponding data table of the sound velocity and temperature of water, so that the distance between adjacent receiving transducers is such that the water temperature difference is more than 1°C.

[0024] Furthermore, a plurality of the receiving transducers in a vertical column use the same cable to transmit the received signal to the system host. The cable signal transmission includes power supply, ground line, and multiple signal lines, and separate frequency impedance matching is performed on the multiple signal lines.

[0025] Furthermore, the host is used to filter and delete abnormal signals, calculate the signal-to-noise ratio of the received signal of each receiving transducer, and obtain the weight ratio of each received signal; and then calculate the average signal arrival time as the actual measurement signal arrival time based on the weight ratio of each received signal.

[0026] The technical advantages brought by the system and deployment control method of the present invention are as follows:

[0027] (1) Compared with the existing systems that mostly use integrated transceiver transducers and a single-transmitter-single-receiver channel control method, multiple receiving transducers are not arranged vertically according to depth, and mutual echo interference and the influence of water depth and temperature on sound speed are not considered.

[0028] The river acoustic tomography flow measurement system of the present invention utilizes a multi-channel receiver design with single transmission and multiple receptions, as well as a unique layout control method that considers the influence of wavelength and water temperature. Combined with a multi-parameter weighting algorithm, this system addresses the problem of acoustic tomography transmission in water. This problem is caused by variations in water temperature, impurities, and water pressure at the transducer due to factors such as climate, sunshine duration, geographic location, and interference from ship traffic, which can lead to deterioration or loss of acoustic signal reception quality. The method and system of the present invention overcome the influence of external environmental factors on the quality of sound lines and acoustic signals, resulting in more accurate measurements and calculations.

[0029] The present invention employs independently functioning transmitting and receiving transducers. A transmitting transducer is installed on one side of the riverbank to transmit signals, while a matching vertical row of receiving transducers is installed on the opposite side of the riverbank to receive acoustic signals. This not only reduces the mutual interference of multiple acoustic echoes transmitted on the same side, but also utilizes receiving transducers installed at different depths. When encountering changes in water temperature, impurities, and water pressure within the transducers, the signal reception status of multiple receiving transducers is comprehensively considered, preventing the impact of a single receiving transducer failure on the overall situation and compensating for the loss of a single received signal. This enhances the signal's anti-interference capability, improves the received signal quality, and improves the stability and durability of the measurement.

[0030] (2) Through a large number of experiments, the present invention team found that keeping the distance between the transmitting transducer and the nearest receiving transducer at more than twice the wavelength can avoid being too close to each other and causing interference when transmitting due to rebound sound waves. In addition, the water temperature at the location of the vertically arranged transducer is collected; the host establishes a data table corresponding to the sound velocity and temperature of water based on the change of the sound velocity of the water body at different temperatures, calculates and adjusts the layout spacing of each vertically arranged receiving transducer, and makes the distance between adjacent receiving transducers separate so that the water temperature difference is more than 1°C. Because it is found that the temperature stratification of some riverbeds in the middle of the river is serious, different temperatures have a great impact on the sound velocity. When the sound line has begun to be obviously stratified in the riverbed, the adjacent layout spacing calibrated according to the water temperature can also be shortened or lengthened. The layout method of the present invention can greatly eliminate the influence of the water environment on the change of sound velocity, reduce interference, and improve the quality of the received sound wave signal and the measurement stability. The experiment proves that the signal measurement accuracy of the present invention method is 6-8% higher than that of the above-mentioned existing measurement method. The system maintains measurement stability for over two years, 2-3 times greater than existing measurement systems. It is particularly adaptable to measuring rivers in northern China subject to ice and heavy rain. This is because the system comprehensively considers the impact of different water layer temperatures on sound velocity and incorporates a multi-parameter weighting algorithm to improve measurement accuracy.

[0031] (3) This system uses independent transmitting and receiving transducers, which is more cost-effective. A vertical row of receiving transducers uses the same cable, and frequency impedance matching is performed on multiple signal lines separately. This improves the stability of signal acquisition. This design can significantly reduce the number of maintenance personnel and facilitates deployment on the river bank. The host is highly intelligent, has fast computing speed, and is more anti-interference and adaptable. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the schematic diagram of the amplification circuit of the system receiving transducer.

[0033] Figure 2 This is a schematic diagram of a single-transmitter, multi-receiver multi-channel system for river acoustic tomography flow measurement according to the present invention.

[0034] Figure 3 It is a sonic temperature gauge of water in the method of the present invention.

[0035] Figure 4 It is a schematic diagram of a plurality of receiving transducers arranged vertically in a row according to the present invention.

[0036] Figure 5 It is a schematic diagram of the signals received by the five receiving transducers.

[0037] Figure 6 Schematic diagram of a cable connecting multiple receiving transducers. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the invention will be described clearly and completely below with reference to the accompanying drawings in this embodiment.

[0039] An embodiment of the present invention provides a method for controlling the deployment of a multi-channel system with single-transmitter and multiple-receiver functions based on river acoustic tomography flow measurement, which adopts the following steps.

[0040] Step (1) uses a transmitting transducer and a receiving transducer with independent functions, and arranges multiple receiving transducers in a row vertically downward and at a certain distance. In response to changes in the sound speed of the water body, each receiving transducer performs single-channel frequency impedance matching to maintain matching in receiving sensitivity.

[0041] For the operating frequency (frequency band) of the transmitting transducer, each receiving transducer has relatively consistent receiving sensitivity in the operating frequency band, that is, the frequency band receiving sensitivity error of the receiving transducers installed in the same river section is ±1.5dB. The frequency impedance characteristics of the receiving transducers are measured using an impedance analyzer for unified matching adjustment.

[0042] Step (2) adjusts the receiving gain of the pre-stage amplifier to improve the transmission quality of the received signal, and adjusts the amplification gain of the pre-stage amplifier according to the receiving sensitivity of each receiving transducer at the operating frequency.

[0043] like Figure 1 As shown, the system receives the amplifying circuit of the transducer, and the back end is connected to the AD acquisition circuit.

[0044] Adjust the receiving gain of the pre-amplifier, that is, adjust the ratio of R4 / R3 and R7 / R6 to achieve the best reception signal transmission, and adjust the pre-amplification gain according to the receiving sensitivity of each receiving transducer at the operating frequency (frequency band), so that each receiving transducer can have an electrical signal of uniform size (2.7V~3.3V for the single-chip microcomputer system) on the electrical signal collected by the system AD after amplification, and then transmit the amplified signal back to the main computing device for data analysis.

[0045] For example, in the adjustment process, the receiving sensitivity of receiving transducer A is -200dB (V / uPa), and the receiving sensitivity of receiving transducer B is -160dB. Because the optimal acquisition voltage of the AD acquisition circuit is between 2.7 and 3.3V (calculated according to 3.2V), and calculated according to the sound intensity of 200uPa, for receiving transducer A, the ratio of R4 / R3 and R7 / R6 needs to be adjusted to 3.2, which is 10.1dB gain; for receiving transducer B, the values ​​of R4 / R3 and R7 / R6 need to be adjusted to reach a voltage of 3.2V on the AD acquisition circuit, then the value of R4 / R3 of transducer B should be 2.56, which is 8.16dB gain.

[0046] Step (3): According to the change of water sound velocity at different temperatures, the layout spacing of each vertically arranged receiving transducer is adjusted, and the distance between adjacent receiving transducers is such that the water temperature difference is greater than 1°C.

[0047] like Figure 2 As shown, the multi-channel system of single-transmitter and multi-receiver based on river acoustic tomography flow measurement of the present invention includes a host (not shown in the figure), multiple transmitting transducers and receiving transducers with independent functions; it can also include a wireless transmission device, and the host can connect the transmitting transducer and the receiving transducer through a wireless network or a data cable. The multiple receiving transducers are formed into a row vertically downward and arranged at a certain interval. As an embodiment of the layout control method, a transmitting transducer with independent function can be set on one side of the river bank, and a corresponding row of multiple receiving transducers can be set vertically on the opposite bank of the river to form the simplest system architecture. Of course, more transmitting transducers and receiving transducers can be added according to the actual width and depth of the river.

[0048] The transmitting transducer and receiving transducer are arranged on the same side of the river channel, and the distance between the transmitting transducer and the nearest receiving transducer is kept at more than 2 times the wavelength. This can avoid being too close to each other and causing interference due to rebound sound waves during transmission.

[0049] In addition, based on the accumulation of a large amount of experimental data in the early stage, a water sound speed temperature table was established. Figure 3 .

[0050] Multiple receiving transducers are deployed on the same side of the river, arranged vertically in a row. The spacing between each vertically arranged transducer is adjusted based on the variations in sound velocity at different water layer temperatures. Adjacent transducers are spaced so that the water temperature difference is at least 1°C. The exact distance between these 1°C intervals depends on the actual riverbed temperature. The water temperature difference between adjacent transducers must be at least 1°C, and ideally, the distance between them should be at least twice the wavelength to minimize signal interference.

[0051] The bottom receiving transducer is fixed by a heavy pile to ensure that the whole row of multiple receiving transducers is vertically downward. Figure 4 As shown in the figure, there are five receiving transducers, and the distances between them are L1, L2, L3, and L4 respectively. Because the temperature stratification of some riverbeds in the middle of the river is serious, if the sound line has begun to stratify in the middle of the riverbed, the water temperature calibration distance can also be shortened or lengthened for this reason; Figure 4 The lengths of L1, L2, L3, and L4 are all determined by the speed of sound at the underwater location.

[0052] In step (4), after a row of vertical receiving transducers receives the sound waves transmitted by the transmitting transducer on the opposite side of the river, the signal-to-noise ratio of the received signal of each receiving transducer is calculated to obtain the weight ratio of each received signal. Based on the weight ratio of each received signal, the average signal arrival time is calculated as the actual measured signal arrival time.

[0053] Specifically, after the deployment is completed, the acoustic tomography system drives the transmitting transducer through the host to send sound waves, and matches a corresponding row of multiple receiving transducers set on the other side of the river. After receiving the sound waves from the opposite side, the signal transmitted back by each receiving transducer is analyzed, and abnormal signals such as poor signals, overly strong signals and no signals are deleted. The average signal arrival time is calculated according to the weight ratio of the remaining signals as the actual measurement signal arrival time.

[0054] For example: receiving transducers 1 to 5 all transmit signals back, and the arrival times of the signals are t1, t2, t3, t4, and t5 respectively. According to the temperature of each transducer and the algorithm, the weight ratio x of each transducer is obtained. According to the formula t=x1×t1+x2×t2+x3×t3+x4×t4+x5×t5, the average time t is calculated.

[0055] The test example is as follows: the signals received by the five transducers are as follows Figure 5 , the signal-to-noise ratios of the calculated signals are 25.6, 36.3, 43, 34.7, and 30.2 respectively. Then according to the formula Q1 is the weight ratio of signal 1, X1 is the signal-to-noise ratio of signal 1, and (X1+X2+X3+X4+.......+Xn) is the sum of all signal-to-noise ratios. The weight ratio of each signal is calculated, and the five signals will be calculated with normalized signal-to-noise ratios of 0.15, 0.21, 0.25, 0.20, and 0.18 as the weight calculation results.

[0056] Among the signals received by the five transducers, each signal has an arrival time (t1, t2, t3, t4, t5). The average arrival time is calculated based on the weight ratio of the five signals. The formula is as follows:

[0057] t=0.15×t1+0.21×t2+0.25×t3+0.20×t4+0.18×t5

[0058] By taking multiple measurements and using statistical methods to obtain more stable arrival time results with smaller errors, the final average time of the section is obtained, which can be used to calculate more accurate river flow results later.

[0059] The second embodiment of the present invention further provides a multi-channel system based on river acoustic tomography flow measurement with single transmission and multiple reception, which adopts the above method of the present invention, such as Figure 2As shown, the system includes a host (not shown), multiple independently functioning transmitting transducers and receiving transducers; it may also include a wireless transmission device, and the host can connect the transmitting transducer and the receiving transducer via a wireless network or data cable. The multiple receiving transducers are arranged vertically downward in a row and at a certain distance. In response to changes in the sound velocity of the water, each receiving transducer performs single-channel frequency impedance matching to maintain matching in receiving sensitivity. According to the changes in the sound velocity of the water at different temperatures, the layout spacing of each vertically arranged receiving transducer is adjusted, and the distance between adjacent receiving transducers is separated to ensure that the water temperature difference is at least 1°C.

[0060] A row of vertical receiving transducers receives the sound waves from the sending transducer on the opposite side of the river and transmits them to the host. The host is used to eliminate excessively poor signals, excessively strong signals and abnormal signals, and calculates the average signal arrival time as the actual measurement signal arrival time based on the weight ratio of the remaining signals.

[0061] The host is also used to adjust the receiving gain of the pre-stage amplifier to improve the transmission quality of the received signal, and adjust the amplification gain of the pre-stage according to the receiving sensitivity of each receiving transducer at the working frequency.

[0062] The transmitting transducer and receiving transducer are arranged on the same side of the river channel, and the distance between the transmitting transducer and the nearest receiving transducer is maintained at more than 2 times the wavelength; the system also includes a temperature detector, which is arranged on multiple receiving transducers arranged on the same side of the river channel to collect the water temperature at the position where the vertically arranged transducers are located; the host calculates and adjusts the layout spacing of each vertically arranged receiving transducer according to the change of water sound velocity at different temperatures and refers to the water sound velocity and temperature corresponding data table. The distance between adjacent receiving transducers is such that the water temperature difference is more than 1°C.

[0063] like Figure 6 As shown, a vertical row of multiple receiving transducers all use the same cable to transmit the received signal to the system host. The cable signal transmission includes power supply, ground line, and multiple signal lines, and frequency impedance matching is performed separately for the multiple signal lines.

[0064] The host is used to filter and delete excessively poor signals, excessively strong signals and abnormal signals, calculate the signal-to-noise ratio of the received signal of each receiving transducer, and obtain the weight ratio of each received signal; then, based on the weight ratio of each received signal, calculate the average signal arrival time as the actual measurement signal arrival time.

[0065] This invention, based on a single-transmitter, multiple-receiver multi-channel system for river acoustic tomography flow measurement, addresses the problem of poor signal reception or signal loss during acoustic tomography transmission, caused by variations in water temperature, impurities, and water pressure at the transducer due to factors such as climate, sunshine duration, geographic location, and human interference. Experimental testing has shown that existing systems using a single transmitter and a single receiver have a 6-8% probability of receiving weak or even sudden signal loss in rivers over 100 meters wide and 12 meters deep. However, testing using the system of this invention has reduced the probability of this occurring to approximately 0.2%.

[0066] All external environmental factors can cause changes in multiple sound lines, such as Figure 4 For example, if the water temperature, impurities, or water pressure changes within the transducer, receiving transducer 1 may completely lose any signal, while receiving transducer 2 may receive overlapping signals arriving from multiple paths. If transducers 3, 4, and 5 are installed on the same vertical plane, the transmitted sound wave signal can be guaranteed to be received, compensating for the signal loss from receiving transducers 1 and 2 and enhancing the signal's anti-interference capabilities. This structural design significantly reduces maintenance requirements while ensuring real-time signal stability and longevity.

[0067] The method and system of the present invention arrange multiple receiving transducers vertically downward and at a certain interval to cope with the situation where some transducers cannot receive signals due to changes in the sound speed of the water body; single-channel frequency impedance matching is performed for each receiving transducer, and each transducer maintains approximately consistent receiving sensitivity (with an error of ±1.5dB), and multiple AD channels are used for simultaneous acquisition to reduce interference and improve signal quality. The temperature changes at the positions of the vertically arranged transducers are collected, and the arrangement spacing of each receiving transducer is determined according to the changes in the sound speed of the water body at different temperatures, which can greatly improve the stability of the received signal.

Claims

1. A multi-channel system deployment control method for single-transmitter and multi-receiver based on river acoustic tomography flow measurement, characterized in that: Including steps: (1) Using independent transmitting and receiving transducers, multiple receiving transducers are arranged vertically downward in a row at a certain distance. To cope with the change of water sound velocity, each receiving transducer performs single-channel frequency impedance matching to ensure matching in receiving sensitivity. (2) Adjust the receiving gain of the pre-amplifier to improve the quality of the received signal transmission, and adjust the amplification gain of the pre-amplifier according to the receiving sensitivity of each receiving transducer at the operating frequency; so that each receiving transducer can have a unified electrical signal on the electrical signal collected by the system AD after amplification; (3) In terms of the layout of the receiving transducers, according to the change of water sound velocity at different temperatures, the layout spacing of each vertically arranged receiving transducer is adjusted, and the distance between adjacent receiving transducers is such that the water temperature difference is more than 1°C; (4) After a row of vertical receiving transducers receives the sound waves transmitted from the transmitting transducer on the opposite side of the river, the abnormal signals are removed, and the average signal arrival time is calculated as the actual measurement signal arrival time based on the weight ratio of the remaining signals; specifically, it includes: after a row of vertical multiple receiving transducers receives the sound waves transmitted from the transmitting transducer on the opposite side of the river, the abnormal signals are filtered and removed, and the signal-to-noise ratio of the receiving signal of each receiving transducer is calculated to obtain the weight ratio of each receiving signal; and then the average signal arrival time is calculated as the actual measurement signal arrival time based on the weight ratio of each receiving signal.

2. The method for controlling the deployment of a multi-channel system for single-transmitter and multi-receiver based on river acoustic tomography flow measurement according to claim 1, characterized in that: Step (3) specifically includes: The transmitting transducer and the receiving transducer are arranged on the same side of the river channel, and the distance between the transmitting transducer and the nearest receiving transducer is kept at more than 2 times the wavelength; Multiple receiving transducers are arranged on the same side of the river channel to collect the water temperature at the location of the vertically arranged transducers. According to the change of water sound velocity at different temperatures and the corresponding data table of water sound velocity and temperature, the layout spacing of each vertically arranged receiving transducer is calculated and adjusted. The distance between adjacent receiving transducers is such that the water temperature difference is more than 1°C.

3. The method for controlling the deployment of a multi-channel system with single-transmitter and multiple-receiver functions based on river acoustic tomography flow measurement according to any one of claims 1 to 2, characterized in that: A plurality of the receiving transducers in a vertical row all use the same cable to transmit the received signal to the system host. The cable signal transmission includes power supply, ground wire, and multiple signal lines, and frequency impedance matching is performed separately for the multiple signal lines.

4. A multi-channel system for single-transmitter and multi-receiver flow measurement based on river acoustic tomography, characterized in that: The system includes a main unit, multiple independent transmitting and receiving transducers. Multiple receiving transducers are arranged vertically downward in a row at a certain distance. To cope with changes in water sound velocity, each receiving transducer performs single-channel frequency impedance matching to ensure matching in receiving sensitivity. The spacing between each vertically arranged receiving transducer is adjusted based on changes in water sound velocity at different temperatures. Adjacent receiving transducers are spaced so that the water temperature difference is at least 1°C. A vertical row of multiple receiving transducers receives the sound waves from the transmitting transducer on the opposite side of the river and transmits them to the host. The host is used to eliminate abnormal signals and calculate the average signal arrival time as the actual measurement signal arrival time based on the weight ratio of the remaining signals; The host is used to filter and delete excessively poor signals, excessively strong signals and abnormal signals, calculate the signal-to-noise ratio of the received signal of each receiving transducer, and obtain the weight ratio of each received signal; then, based on the weight ratio of each received signal, calculate the average signal arrival time as the actual measurement signal arrival time.

5. The multi-channel system for single-transmitter and multiple-receiver flow measurement based on river acoustic tomography according to claim 4, characterized in that: The host is also used to adjust the receiving gain of the pre-stage amplifier to improve the transmission quality of the received signal, and adjust the amplification gain of the pre-stage according to the receiving sensitivity of each receiving transducer at the working frequency.

6. A multi-channel system for single-transmitter and multiple-receiver flow measurement based on river acoustic tomography according to claim 4, characterized in that: The transmitting transducer and the receiving transducer are arranged on the same side of the river channel, and the distance between the transmitting transducer and the nearest receiving transducer is maintained at more than 2 times the wavelength; The system also includes a temperature detector for collecting the water temperature at the location of the vertically arranged transducers arranged on the same side of the river channel; the host calculates and adjusts the layout spacing of each vertically arranged receiving transducer based on the change of water sound velocity at different temperatures and with reference to the water sound velocity and temperature corresponding data table, so that the distance between adjacent receiving transducers is such that the water temperature difference is more than 1°C.

7. The multi-channel system for single-transmitter and multi-receiver flow measurement based on river acoustic tomography according to claim 4, characterized in that: A plurality of the receiving transducers in a vertical row all use the same cable to transmit the received signal to the system host. The cable signal transmission includes power supply, ground wire, and multiple signal lines, and frequency impedance matching is performed separately for the multiple signal lines.

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