CN111693728A - Water flow tracing real-time monitoring system and speed measuring method - Google Patents

Abstract

The invention discloses a real-time monitoring system for water flow tracing and a speed measuring method. The water flow tracking real-time monitoring system includes a water flow tracking ball, and the water flow tracking ball includes a positioning module, a communication module, a control module, a power supply module and a spherical waterproof casing. The positioning module is used to obtain the location and time data of the water flow tracking ball regularly or irregularly. The control module is used to cache the positioning data and time data. The communication module regularly or irregularly sends the positioning and time data to the cloud platform monitoring system. The waterproof casing floats on the water surface with a certain water immersion ratio. The water flow tracer ball has low production cost, long battery life, simple speed measurement operation, and high degree of automation, which can better adapt to breakwater, flood peak, bay flow field, tidal zone boundary and tidal boundary of tidal rivers, and mouth waterways. The surface velocity and flow field measurement of extreme scenarios such as storm surges and special terrain waters. The invention belongs to the technical field of hydrological data measurement.

Description

A real-time monitoring system and velocity measurement method for water flow tracing

technical field

The invention relates to the technical field of hydrological data measurement, and relates to a real-time monitoring system for water flow tracing and a speed measurement method.

Background technique

The flow velocity is an important parameter to be obtained in the hydrological observation of rivers, lakes, seas and other water bodies. At present, there are various river flow velocity measuring instruments in the water conservancy industry. In the existing technology, instruments such as buoys, rotor velocity meters, hand-held radar velocity measuring instruments and acoustic Doppler profile velocity measuring instruments are usually used to measure the water flow velocity. The traditional buoy measurement technology needs to set the buoy at a specific position on the water surface, and use the geometric method to calculate the water flow speed. The measurement position is limited and the efficiency is low; in recent years, the buoy has been improved by combining GPS satellite positioning technology and Internet of Things technology. The flow velocity measurement method has made great progress, but there are still some limitations in flow velocity measurement and cost efficiency; the rotor flow meter can generally only measure the water flow velocity of a specific nearshore water body, and it also needs carrier tools such as boats or steel cables to measure far away from the river bank. hand-held radar velocity meter generally can only measure the water flow velocity within 50m near the shore, the application range is limited, it is difficult to measure the flow velocity of medium and large rivers; the acoustic Doppler profile velocity meter is expensive and requires the help of boats or steel cables It can only be measured by waiting for a carrier tool, and the measurement cost is relatively high, so it is not suitable for measurement occasions where there is a possibility of instrument loss such as embankment breakage and flooding. The above-mentioned various flow velocity measuring instruments have their own advantages and are suitable for different surveying and mapping scenarios and uses, but they also have certain limitations, such as expensive equipment, high monitoring costs, etc. Real-time monitoring of flow rate and accurate measurement over a wide range.

SUMMARY OF THE INVENTION

In view of at least one of the above technical problems, the purpose of the present invention is to provide a real-time monitoring system for water flow tracing and a method for measuring speed.

On the one hand, an embodiment of the present invention includes a water flow tracking real-time monitoring system, including at least one water flow tracking ball, and the water flow tracking ball includes:

Positioning module: used to obtain the position and time data of the water flow tracking ball regularly or irregularly, and the cloud platform can measure the moving speed of the water flow tracking ball according to the position and time interval sent back by the water flow tracking ball;

Communication module: used for data communication between the water flow tracer ball and the cloud platform;

Control module: connected with the positioning module and the communication module respectively, used to cache the positioning data and the time data corresponding to the positioning data, and send the positioning data and time data to the cloud platform regularly or irregularly through the communication module;

Power supply module: supply power to each module of the water flow tracer ball;

Spherical protective casing: used to encapsulate the positioning module, the communication module, the control module and the power supply module; the spherical waterproof casing floats on the water surface with a certain water immersion ratio when placed in the water body.

Further, the water flow tracking ball also includes:

The magnet switch is connected between the power supply module and the load, and is used for turning on or off when triggered by an external magnetic field; the load includes at least one of the positioning module, the communication module or the control module.

The magnet switch is enclosed within the spherical waterproof housing.

Further, the magnet switch includes a reed and a PCD/SMD sensor, the reed is connected between the power supply module and the load, and the PCD/SMD sensor is used to drive the reed guide when triggered by an external magnetic field. on or off.

Further, through the synchronous velocity measurement experiments of different flow meters in the river, the optimal water immersion ratio (k) of the water flow tracer ball is determined, which is closely related to the size and total mass of the water flow tracer ball; the optimal water immersion specific energy The water flow tracking ball is made to follow the water flow relatively stably, so as to ensure that the moving speed of the water flow tracking ball can most closely characterize the water flow speed and reduce the speed measurement error. The value of the following coefficient (f) is closely related to the submersion ratio (k), and is affected by the weather, especially the wind speed. After multiple simultaneous measurement experiments of different river channels and multiple current meters in the field, it is suggested that the value ranges of the two are: k∈(0.65, 0.95), f∈(0.90-1.20).

On the other hand, the embodiment of the present invention "a real-time monitoring system and speed measurement method for water flow tracing" also includes at least one set of remote real-time monitoring system and speed measurement method:

Cloud platform: No separate server is set up, but it is deployed on the public cloud platform to receive the position and time information sent by the water flow tracker ball, measure the movement speed of the water flow tracker ball, and query and display the movement trajectory and time of the water flow tracker ball. Instantaneous speed, for users to log in online, monitor and download in real time the position, time, speed and other data of the water flow tracer ball, and use it to determine the water flow speed according to the spatiotemporal distribution of each of the water flow tracer balls.

Further, the remote real-time monitoring system and the speed measurement method also include at least one speed measurement method, which determines the water flow speed according to the position and time information sent back by the water flow tracking ball, including:

Determining the instantaneous moving speed of the water current tracking ball: the instantaneous moving speed is the ratio of the moving distance of the water current tracking ball to the time in a short time range, such as every 1 minute; in order to reduce the positioning deviation of the water current tracking ball The resulting instantaneous velocity deviation, the instantaneous velocity per minute reported by the water flow tracer ball is the sliding average over 5 minutes, i.e. the instantaneous velocity of the water flow tracer ball reported at the 6th minute is the one moving between the 2nd and 6th minutes. The ratio of distance (m) to time (300s), and the flow direction (θ) is determined according to the relative positions (x ₂ , y ₂ ) and (x ₁ , y ₁ ) of the water flow tracer ball at two moments; the water flow velocity (V _w ) is equal to the velocity of the water tracker ball (V _b ) multiplied by the followability coefficient (f), as shown in equations (1) and (2):

V _w = fV _b (1)

When y ₂ ≥ y ₁ , θ is located in the first and second quadrants; when y ₂ <y ₁ , θ is located in the third and fourth quadrants.

Further, the remote real-time monitoring system and the speed measurement method also include at least a speed measurement method, and the water flow speed measurement method is determined according to the position and time information sent back by the water flow tracking ball, including:

Determine the interval (period) average speed of the water flow tracer ball: the interval (period) average speed is the ratio of the total distance moved by the water flow tracker ball to the interval time in the interval (period), and the interval ( period) distance is determined by the first positioning data and the last positioning data of the water flow tracking ball in this interval (period), and the time used in the interval (period) is determined by the water flow tracking ball in this interval (period) The difference between the time corresponding to the first positioning data and the time of the last positioning data is determined. The water flow velocity is equal to the moving velocity of the water flow tracer ball multiplied by the followability coefficient, see formula (1).

Further, the remote real-time monitoring system and the speed measurement method also include at least one speed measurement method, and the cloud platform determines the water flow speed measurement method according to the position and time information sent back by the water flow tracking ball, including:

Exclude velocity outliers: the velocity of the river flow is affected by various factors, such as the position of the river section: the middle is large, the near-shore is small), the tidal time of the tidal reaches: the flow direction is opposite when the tide is rising and falling, and the speed is when the rising and falling are sharp. The velocity value is close to zero at flat tide and low tide; based on the position of the river section, the tide time and the moving trajectory of the water flow tracer ball, a comparative analysis is made, and the abnormal velocity value is eliminated to determine the reasonable water flow at different positions of the river section. speed value.

Taking the calculation of the hourly average velocity as an example, the anomalous value of the instantaneous distance is eliminated, and the average velocity is calculated. The hourly average speed of the water current tracking ball refers to the ratio of the distance moved by the water current tracking ball to the time within a period of one hour. The sum of the distance moved in minutes, the time is 3600s.

When calculating the distance sum in the hourly range, it is necessary to evaluate the quality of the distance that the water current tracker moves per minute to reduce the velocity measurement error caused by the positioning error, as shown in formula (3):

S ₀ represents the average moving distance of the water flow tracer ball in every 1 (or 2-5) minute in the hour, S _i represents the distance moved by the water flow tracer ball in the ith minute, and a represents the water flow The absolute value of the anomaly within the hour range for the distance the tracer ball moved in the ith minute. If a is greater than 25% (other thresholds can also be set as required), remove S _i ; and recalculate S ₀ in the hour range, and replace the rejected Si with new S _{0 ,} and calculate the water flow tracking ball The sum of the distances moved within the hour range, and then calculate the average speed value V _b of the water current tracking ball moving within the hour, as shown in formula (4): .

After the quality inspection and screening of the formula (1), the abnormal value of the moving distance of the water flow tracer ball per minute can be eliminated, and the accuracy and reliability of the velocity value calculated by the formula (4) can be ensured. When the time interval of the distance Si is 1 minute, _n =60; when it is 5 minutes, _n =12; in order to reduce the accumulated distance error caused by the positioning error, it is recommended that the optimal time interval of the distance Si is 3-5 minutes. The water flow velocity is equal to the moving velocity of the water flow tracer ball multiplied by the followability coefficient, see formula (1).

The beneficial effects of the present invention are as follows: the "a real-time monitoring system and speed measuring method for water flow tracing" in the embodiment is different from the traditional remote monitoring method which needs to set up a separate monitoring server, the method of the present invention arranges the real-time monitoring system on the public cloud platform The water flow tracking ball manufacturer is responsible for management and maintenance. Users do not need to purchase monitoring equipment such as servers and monitoring software development. They only need to purchase water flow tracking balls to measure speed, and use mobile phones or computer terminals to surf the Internet to implement remote monitoring and download data. . The water flow tracer ball has the advantages of low production cost, long battery life, simple speed measurement operation and high degree of automation. We optimized the best water immersion ratio and followability of the water flow tracer ball, and designed the speed measurement method to eliminate outliers and ensure the accuracy and reliability of the measurement data. In addition to tracking monitoring and speed measurement of conventional water flow, it can also conduct real-time monitoring of large-scale flow velocity and flow direction in extreme water flow environments such as flood peaks and storm surges, which can better adapt to breakwater, flooding, bay flow fields, and tide sensing. Extreme scenarios and special terrains such as the tidal zone boundary and tidal boundary of rivers, the two-way jet in the mouth of the waterway, and storm surges have broad application prospects and great social and economic value.

Description of drawings

FIG. 1 is a physical diagram of the water flow tracking ball positioning device in Example 1. FIG.

FIG. 2 is a schematic diagram of a startup or shutdown method of the water flow tracer ball in Example 1. FIG.

FIG. 3 is a schematic diagram of the movement track of the water flow tracer ball in the water body when the flow velocity of the river is measured in Example 3. FIG.

FIG. 4 is a schematic diagram of the instantaneous flow velocity measured when the river flow velocity measurement is performed in Example 3. FIG.

FIG. 5 is a schematic diagram of the hourly average flow velocity measured when the river flow velocity measurement is performed in Example 3. FIG.

Detailed ways

Example 1

The water flow tracking real-time monitoring system in this embodiment includes a plurality of water flow tracking balls, and each water flow tracking ball includes a positioning module, a communication module and a control module. The positioning module may be a GPS satellite signal receiving chip or a Beidou satellite signal receiving chip, and the communication module may include a narrowband Internet of Things NB-IOT and a GPRS dual communication chip. The control module can be a single microcontroller, or the positioning module, the communication module and the control module can be integrated together through technologies such as SOC.

The water flow tracking ball in this embodiment further includes a power supply module and a magnet switch. The power supply module may be a 3.6V/9Ah lithium power supply module group, and the power supply modules are respectively connected with the positioning module, the communication module and the control module.

The magnet switch includes reeds and PCD/SMD sensors, and the reeds are connected between the power supply module and loads such as positioning modules, communication modules and control modules. When the reed is in the off state, the connection between the power supply module and the load is disconnected, and the water flow tracer ball is in a power-off state. At this time, when an external magnetic field such as a magnet is used to approach the PCD/SMD sensor for about 5s, the PCD/SMD sensor will be closed. The SMD sensor drives the reed to conduct, the connection between the power supply module and the load is connected, and the water flow tracer ball is in the power-on state. When the reed is in the on state, the connection between the power supply module and the load is connected, and the water flow tracer ball is in the power-on state, when the external magnetic field such as a magnet is used to approach the PCD/SMD sensor for about 5s, the PCD/SMD The sensor drives the reed to turn off, the connection between the power supply module and the load is disconnected, and the water flow tracking ball is in a power-off state.

The positioning module, the communication module, the control module, the power supply module and the magnet switch are sealed in a spherical waterproof casing, optionally, the spherical waterproof casing is spherical in shape and has an IP68 degree of protection. In this embodiment, the physical appearance of the water flow tracking ball is shown in FIG. 1 . Due to the magnet switch, as shown in Figure 2, use a magnet close to the water flow tracking ball to turn on or off the water flow tracking ball, and avoid setting a mechanically movable switch on the spherical waterproof shell to affect the waterproof reliability of the spherical waterproof shell .

In this embodiment, the positioning module obtains satellite data from GPS satellites or Beidou satellites at a frequency of (30-60000) s/time. The control module obtains the satellite data from the positioning module to analyze and obtain the positioning data. The positioning data mainly includes the latitude, longitude and positioning time information. The positioning data and time data are used to describe the space-time coordinates of the water current tracking ball, and to measure the moving distance, direction and speed of the water current tracking ball.

In this embodiment, the control module sends its buffered positioning data and time data to the outside through the communication module at a frequency of (60-60000) s/time, which can effectively deal with the situation of poor communication, such as when encountering a communication failure. When the control module cannot send the positioning data and time data, the control module can store the positioning data and time data in it, and send it after the communication is restored.

In this embodiment, the water immersion ratio (k) of the water flow tracer ball refers to the ratio of the volume of the part of the water flow tracer ball immersed below the water surface to the total volume. After the diameter of the spherical waterproof shell is basically determined, the size of the water immersion ratio is related to the total mass of the water flow tracking ball. In the present invention, the moving speed of the water flow tracking ball represents the water flow speed, so the followability of the water flow tracking ball to the water flow is very important, and the best following performance of the water flow tracking ball is determined to ensure that the moving speed of the water flow tracking ball can be the closest to the water flow. To characterize the water flow velocity, a relatively stable follow-up coefficient (f) of the water flow tracer ball to the water flow is obtained, and the measurement error of the flow velocity is reduced. The water immersion ratio of the water flow tracer ball determines the value and stability of the followability between the movement speed of the water flow tracer ball and the water flow speed, and the optimal water immersion ratio parameter of the water flow tracer ball is related to the The size is related to the total mass and needs to be determined by the synchronous speed measurement experiment of different water flow speed meters on site. Through on-site synchronous monitoring tests of various velocimeters in different waterways, the following coefficients (f) of water flow tracer balls of the same diameter at different flooding ratios and different river flow velocity were verified. In this embodiment, the diameter of water flow tracer balls is determined. The optimal water immersion ratio is k ± 2%. The submersion ratio within this range can make most of the water current tracer ball below the water surface, reduce the influence of wind-induced waves and ship traveling waves, and obtain a relatively stable flow velocity following coefficient (f); it can also keep part of the water outside the water surface, which is convenient for measurement Recycling after completion.

In this embodiment, a light-emitting device can be set outside the spherical waterproof casing. When a trigger event such as the control module timing to a set value or monitoring an instruction sent by the server occurs, the control module instructs the light-emitting device to emit light, so that the measurement can be carried out after the completion of the measurement. Recycling work.

The water flow tracking ball in this embodiment has a low manufacturing cost, can be processed into a small volume, and is convenient to be put into a water body such as a river to obtain positioning data and time data for analysis to obtain the water flow speed; compared with the prior art , due to lower cost, more convenient delivery, and independent of specific manual operation, delivery location, measurement location or measurement conditions, it can better adapt to the tidal zone boundaries of dyke breakage, flooding, bay flow fields, and tidal rivers It has a wide range of application prospects and great social and economic value in extreme scenarios such as the tidal current world, the two-way jet in the Koumen waterway, and the storm surge.

Example 2

The "a real-time monitoring system and speed measurement method for water flow tracing" in this embodiment also includes a set of remote real-time monitoring system and speed measurement method based on a public cloud platform. Different from the traditional method, which needs to set up a separate monitoring server, the method of the present invention arranges the real-time monitoring system on the public cloud, and the water flow tracking ball manufacturer is responsible for management and maintenance. You can measure the speed by purchasing the water current tracking ball, and use the mobile phone or computer terminal to surf the Internet to implement remote monitoring and download data.

It can be seen from the description of Example 1 that the volume of the water flow tracer ball is small, and it can be conveniently placed anywhere in the water body, for example, on a section of a river.

Each water flow tracking ball sends positioning data and time data to the cloud platform. The cloud platform can accurately draw the space-time trajectory of the water current tracking ball moving in the water body based on the received positioning data and time data, and measure the moving direction and speed of the water current tracking ball.

The process that the cloud platform determines the water flow velocity according to the spatiotemporal distribution of each water flow tracer ball includes two steps S1 and S2:

S1. Determine the instantaneous speed of a single water flow tracer ball moving with the water flow in the water body

The instantaneous speed of the water flow tracer ball refers to the ratio of the distance moved by the water flow tracer ball to the time within a short time range, such as every 1 or 5 minutes; Instantaneous velocity deviation, the instantaneous velocity per minute reported by the water current tracer ball is the sliding average over 5 minutes, that is, the instantaneous velocity of the water current tracer ball reported at the 6th minute is the distance traveled between the 2nd and 6th minutes and The ratio of time (300s), and the flow direction is determined according to the relative position of the water flow tracer ball at two moments, see formula (2). The water flow velocity is equal to the moving velocity of the water flow tracer ball multiplied by the followability coefficient, see formula (1).

S2. Determine the hourly average speed of a single water flow tracer ball moving with the water flow in the water body

The hourly average speed of the water current tracking ball refers to the ratio of the distance moved by the water current tracking ball to the interval time within a period of one hour, and the moving distance of the water current tracking ball in the hour The sum of the distance moved per minute, the time period is 1 hour or 3600s. It is also possible to vary the period length for the average flow rate calculation.

When calculating the sum of distances in the hourly range, it is necessary to evaluate the quality of the distance the water current tracker moves per minute to reduce the velocity measurement error caused by the positioning error, as shown in formula (3). After the quality inspection and screening of formula (3), the abnormal value of the moving distance of the water flow tracer ball per minute can be eliminated, and the accuracy and reliability of the velocity value calculated by formula (4) can be ensured. The water flow velocity is equal to the moving velocity of the water flow tracer ball multiplied by the followability coefficient, see formula (1).

Example 3

In this embodiment, the real-time monitoring system for water flow tracing in Embodiment 2 is applied to the flow velocity test of an actual river channel. At 19:47 on November 26, 2019, the current tracking ball numbered 009 was dropped on the front channel of the Pearl River. The front channel of the Pearl River is about 300m wide and belongs to the tidal river section. The river water flows back and forth due to the influence of the tide, and the flow rate will also change due to the different tides. The drop point is in the center of the Haiyin Bridge, and the vertical distance between the bridge and the water surface is about 20m.

The drifting trajectory of the No. 009 water current tracking ball is shown in Figure 3. The ball has been running until 07:37 on November 27, 2019, and moved in the river channel at 11:50 in total. The high tide and the water channel of this section were measured. Velocity change and tidal upper bound during ebb. The instantaneous flow velocity of the No. 009 water flow tracer ball is shown in Figure 4. The instantaneous flow velocity of the No. 009 water flow tracer ball in the second half is generally good, and occasionally there are instantaneous high values, which may be affected by ship waves, or Due to the drift error of the positioning data, data optimization can be performed according to the method described in S1 in Embodiment 2.

Figure 5 shows the hourly average velocity of the No. 009 water flow tracer ball after the cloud platform has processed the raw instantaneous data in Figure 4, and the tidal level change at the north gate of Sun Yat-Sen University in the Pearl River. The flow rate measured by the water flow tracer ball is very good The flow velocity changes during the tidal level change process are revealed, reaching 1.0m/s at 23:00 when the tide rises sharply, 0.85m/s when the tide falls at 6:00 on the 27th, and at 3:00 on the 27th when the high tide turns to ebb tide. The average flow velocity is only 0.2m/s. The data of Fig. 4 and Fig. 5 obtained by using the water flow tracing real-time monitoring system in Example 2 are consistent with the flow velocity variation law measured in the history of the measured river section, indicating that the water flow tracing real-time monitoring system in Example 2 is effective. Measurement performance is reliable.

It should be noted that the descriptions such as upper, lower, left and right used in the present disclosure are only relative to the mutual positional relationship of each component of the present disclosure in the accompanying drawings. As used in this disclosure, the singular forms "a," "the," and "the" include the plural forms as well, unless the context clearly dictates otherwise. Also, unless otherwise defined, all technical and scientific terms used in the examples have the same meaning as commonly understood by one of ordinary skill in the art. The terms used in the description of the embodiments are only used to describe specific embodiments, rather than to limit the present invention. As used in this example, the term "and/or" includes any combination of one or more of the associated listed items.

It will be understood that, although the terms first, second, third, etc. may be used in this disclosure to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish elements of the same type from one another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present disclosure. The use of any and all examples or exemplary language ("for example," "such as," etc.) provided in this embodiment is intended only to better illustrate embodiments of the invention and does not detract from the scope of the invention unless otherwise requested impose restrictions.

It should be appreciated that embodiments of the present invention may be implemented or implemented by computer hardware, a combination of hardware and software, or by computer instructions stored in non-transitory computer readable memory. The method can be implemented in a computer program using standard programming techniques - including a non-transitory computer-readable storage medium configured with a computer program, wherein the storage medium so configured causes the computer to operate in a specific and predefined manner - according to the specific Methods and figures described in the Examples. Each program may be implemented in a high-level process or target terminal-oriented programming language to communicate with a computer system. However, if desired, the program can be implemented in assembly or machine language. In any case, the language can be a compiled or interpreted language. Furthermore, the program can be run on a programmed application specific integrated circuit for this purpose.

Furthermore, the operations of the processes described in this embodiment may be performed in any suitable order unless otherwise indicated by this embodiment or otherwise clearly contradicted by context. The processes described in this embodiment (or variations and/or combinations thereof) may be performed under the control of one or more computer systems configured with executable instructions, and may be executed as code collectively executing on one or more processors (eg, executable instructions, one or more computer programs, or one or more applications), implemented in hardware, or a combination thereof. The computer program includes a plurality of instructions executable by one or more processors.

Further, the methods may be implemented in any type of computing platform operably connected to a suitable, including but not limited to personal computer, minicomputer, mainframe, workstation, network or distributed computing environment, stand-alone or integrated computer platform, or communicate with charged particle tools or other imaging devices, etc. Aspects of the invention may be implemented in machine-readable code stored on a non-transitory storage medium or device, whether removable or integrated into a computing platform, such as a hard disk, an optically read and/or written storage medium, RAM, ROM, etc., such that it can be read by a programmable computer, when a storage medium or device is read by a computer, it can be used to configure and operate the computer to perform the processes described herein. Furthermore, the machine-readable code, or portions thereof, may be transmitted over wired or wireless networks. The invention described in this embodiment includes these and other various types of non-transitory computer-readable storage media when such media includes instructions or programs that implement the steps described above in conjunction with a microprocessor or other data processor. The invention also includes the computer itself when programmed according to the methods and techniques described herein.

A computer program can be applied to input data to perform the functions described in this embodiment to transform the input data to generate output data for storage to non-volatile memory. The output information can also be applied to one or more output devices such as a display. In a preferred embodiment of the present invention, the transformed data represents the physical and tangible target terminals, including specific visual depictions of the physical and tangible target terminals produced on the display.

The above are only preferred embodiments of the present invention, and the present invention is not limited to the above-mentioned embodiments, as long as it achieves the technical effect of the present invention by the same means, all within the spirit and principle of the present invention, do Any modification, equivalent replacement, improvement, etc., should be included within the protection scope of the present invention. Various modifications and changes can be made to its technical solutions and/or implementations within the protection scope of the present invention.

Claims (8)

1. a water flow tracing real-time monitoring system, is characterized in that, comprises at least one water flow tracing ball, and described water flow tracing ball comprises: The positioning module is used to obtain the position data of the water flow tracking ball regularly or irregularly. The cloud platform can measure the moving speed of the water flow tracking ball according to the position data and time interval sent back by the water flow tracking ball ; a communication module for data communication between the water flow tracking ball and the cloud platform; The control module is connected to the positioning module and the communication module respectively, and is used to cache the positioning data and the time data corresponding to the positioning data, and send the positioning data and time data to the cloud platform regularly or irregularly through the communication module; a power supply module for providing power to the positioning module, the communication module and the control module; The spherical waterproof casing is used to encapsulate the positioning module, the communication module, the control module and the power supply module; the spherical waterproof casing floats on the water surface with a certain water immersion ratio when placed in the water body. 2. A kind of water flow tracing real-time monitoring system according to claim 1, is characterized in that, described water flow tracing ball also comprises: a magnet switch, connected between the power supply module and the load, for turning on or off when triggered by an external magnetic field; the load includes at least one of a positioning module, a communication module or a control module; The magnet switch includes a reed and a PCD/SMD sensor, the reed is connected between the power supply module and the load, and the PCD/SMD sensor is used to drive the reed to turn on or off when triggered by an external magnetic field; The magnet switch is enclosed within the spherical waterproof housing. 3. a kind of water flow tracing real-time monitoring system according to claim 1, is characterized in that, described water flow tracing ball determines a water immersion ratio; The water immersion ratio determines the value range and stability of the followability f between the moving speed of the water flow tracer ball and the water flow speed, and the optimal water immersion ratio of the water flow tracer ball and the size and total mass of the water flow tracer ball Relevantly, the water immersion ratio is determined through synchronous speed measurement experiments of different water flow speed meters on site. 4. a water flow velocity measurement method, is characterized in that, uses cloud platform to carry out the following steps: Receive the position and time information sent back by the water current tracking ball according to any one of claims 1-3; Measure the moving speed of the water current tracking ball; Query and display the moving track and instantaneous speed of the water current tracking ball; For users to log in remotely online, monitor and download the position, time and speed of the water current tracking ball in real time. 5. a kind of water flow velocity measuring method according to claim 4, is characterized in that, also comprises: Determining the instantaneous moving speed of the water current tracking ball; the instantaneous moving speed is within a preset time range, and the instantaneous moving speed is the ratio of the distance moved by the water current tracking ball to the time; According to the instantaneous speed per minute reported by the water current tracer ball, determine the sliding average value of the water current tracer ball within 5 minutes; Determine the flow direction according to the relative position of the water flow tracking ball at two moments; The water flow speed is determined according to the moving speed of the water flow tracking ball multiplied by the followability coefficient f. 6. a kind of water flow velocity measuring method according to claim 4, is characterized in that, also comprises: Determine the average speed of the water current tracking ball in the period: the average speed of the water current tracking ball in the period The sum of the distance between the first positioning data and the second positioning data, the distance between the second positioning data and the third positioning data, the distance between the penultimate positioning data and the last positioning data, the The time is determined by the difference between the time corresponding to the first positioning data of the water flow tracking ball in the interval and the time of the last positioning data. 7. a kind of water flow velocity measuring method according to claim 4, is characterized in that, also comprises: Based on the position of the river section, the tide time and the movement trajectory where the water flow tracking ball is located, a comparative analysis is made, and the abnormal velocity value is eliminated; Determine reasonable flow velocity values at different locations of the river section. 8. a water flow velocity measurement method, is characterized in that, comprises the following steps: A plurality of water flow tracer balls according to any one of claims 1-3 are thrown into the water body; The cloud platform receives the positioning and time data sent by the water flow tracking ball, and determines the position and trajectory of the water flow tracking ball; The cloud platform automatically calculates the moving distance, time, instantaneous moving speed and water flow speed of the water flow tracking ball according to the received position and time of the water flow tracking ball; Accept users to log in to the cloud platform, remotely monitor, query and display the movement trajectory and instantaneous speed of the water current tracer ball online in real time, and download the various data described.

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