Water flow velocity measurement method and water flow velocity measurement device

Abstract

The invention discloses a water flow velocity measurement method and a water flow velocity measurement device, and relates to the technical field of radar velocity measurement and water flow measurement, and the method comprises the steps: obtaining the water flow condition of a target water area; the water flow condition comprises a smooth water flow condition and a non-smooth water flow condition; if the water flow condition is a smooth water flow condition, a first control instruction is sent based on the controller, a spindrift maker is arranged in the target water area, and water flow speed measurement is conducted on the target water area where spindrift is made based on water flow speed measurement equipment; the sea spray maker is used for making sea spray with a set height in a speed measuring area of the water flow speed measuring device; and if the water flow condition is a non-smooth water flow condition, performing water flow speed measurement on the target water area based on water flow speed measurement equipment. According to the invention, accurate flow velocity measurement can be carried out on water flow under different water flow conditions.

Description

Technical Field

[0001] The present application relates to the technical field of radar velocity measurement and water flow measurement, and in particular to a water flow velocity measurement method and a water flow velocity measurement device. Background Art

[0002] In the field of water flow velocity measurement, millimeter wave radar has been widely used in flow velocity monitoring due to its advantages of high precision and non-contact measurement. However, existing millimeter wave radars cannot accurately measure the flow velocity of water in a smooth water flow environment. Summary of the invention

[0003] The purpose of the present application is to provide a water flow velocity measurement method and a water flow velocity measurement device, which can accurately measure the water flow velocity under different water flow conditions based on the water flow velocity measurement equipment.

[0004] To achieve the above objectives, this application provides the following solutions:

[0005] In a first aspect, the present application provides a method for measuring water flow velocity, comprising:

[0006] Acquire water flow conditions of the target water area; the water flow conditions include smooth water flow conditions and non-smooth water flow conditions;

[0007] If the water flow condition is a smooth water flow condition, a first control instruction is issued based on the controller, a wave maker is set in the target water area, and the water flow velocity is measured in the target water area after the wave is made based on the water flow velocity measuring device; the wave maker is used to make waves of a set height in the velocity measuring area of ​​the water flow velocity measuring device;

[0008] If the water flow condition is a non-smooth water flow condition, the water flow speed is measured in the target water area based on the water flow speed measuring equipment.

[0009] In a second aspect, the present application provides a water flow velocity measuring device, comprising: a wave maker, a radar velocity measuring component and a processor;

[0010] The wave maker comprises a water flow impact surface, a fixing hole and an adjusting bracket; the water flow impact surface is arranged in the direction of the water flow, and is used to make local water flows impact each other to generate irregular waves and waves; the adjusting bracket is used to adjust the angle and height of the water flow impact surface according to the water depth of the target water area; the fixing hole is used to fix the wave maker at a preset position;

[0011] The radar speed measuring component is arranged downstream of the water flow impact surface, and is used to transmit radar signals to the target area and receive echo signals; the target area is the area where waves are made in the target water area by the wave maker under smooth water flow conditions;

[0012] The processor is connected to the radar speed measurement component and is used to calculate the water flow velocity according to the received echo signal.

[0013] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0014] The present application provides a method and device for measuring water flow velocity, and obtains the water flow conditions of a target water area; the water flow conditions include smooth water flow conditions and non-smooth water flow conditions; if the water flow conditions are smooth water flow conditions, a first control instruction is issued based on a controller, a wave maker is set in the target water area, and based on the water flow velocity measuring device, the water flow velocity of the target water area after the wave is made is measured; the wave maker is used to make waves of a set height in the speed measurement area of ​​the water flow velocity measuring device; if the water flow conditions are non-smooth water flow conditions, the water flow velocity of the target water area is measured based on the water flow velocity measuring device. The present application breaks the smooth state of the water flow by physical means, so that waves are generated on the surface of the water flow, thereby providing a usable reflection target for the water flow velocity measuring device, thereby improving the quality of the echo signal received by the water flow velocity measuring device, and realizing accurate detection of the water flow velocity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A schematic diagram of a flow chart of a water flow velocity measurement method provided in one embodiment of the present application;

[0017] Figure 2 A schematic diagram of the installation of a wave maker provided in one embodiment of the present application;

[0018] Figure 3 An assembly diagram of a gasket and a wave maker provided in one embodiment of the present application;

[0019] Figure 4 A front view of a gasket provided in one embodiment of the present application;

[0020] Figure 5 A top view of a gasket provided in one embodiment of the present application;

[0021] Figure 6 A top view of a wave maker provided in one embodiment of the present application. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0023] At present, millimeter-wave radar cannot detect the flow velocity in a smooth water flow environment. The main reasons are as follows: Smooth water surfaces usually present relatively smooth and glossy mirror properties. Since the electromagnetic waves emitted by millimeter-wave radars propagate in a straight line, when the electromagnetic waves encounter the surface of a smooth water flow, the electromagnetic waves will be reflected almost in the opposite direction of the incident angle. In this case, since the reflection of high-frequency electromagnetic waves on the surface of an object depends on the surface roughness, and the surface of the water flow is too smooth, the electromagnetic waves emitted by the millimeter-wave radar have a higher frequency and a shorter wavelength. In this case, the radar waves can hardly be reflected or scattered on the water surface, resulting in extremely weak signals or almost no echoes. However, the working principle of millimeter-wave radar is to measure the speed or distance of an object by emitting electromagnetic waves and receiving the reflected electromagnetic waves. If the signal strength reflected back to the radar is low, or even there is almost no available echo signal, it will be difficult for the radar to effectively process and analyze the reflected waves, and thus it will be impossible to obtain the speed information of the water flow. On the other hand, the speed of smooth water flow is usually low, and the water surface has almost no fluctuations, so the reflection characteristics of the water flow surface are almost unchanged. In this case, the signal transmission path of the millimeter-wave radar has hardly changed, and the frequency of the reflected wave has hardly changed, making it difficult for the radar to determine the flow rate of the water through the Doppler effect. The Doppler effect that millimeter-wave radar relies on cannot effectively reflect changes in flow rate in smooth water because there is no obvious "fluctuation" on the water surface to change the frequency of the reflected signal.

[0024] The purpose of this application is to provide a water flow velocity measurement method and a water flow velocity measurement device, by designing a "wave maker" to stimulate the water flow to generate waves, thereby improving the quality of the echo signal received by the millimeter wave radar and realizing accurate detection of the water flow velocity.

[0025] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0026] Embodiment 1

[0027] like Figure 1 As shown, this embodiment provides a water flow velocity measurement method, including:

[0028] Step 101: Acquire water flow conditions of a target water area; the water flow conditions include smooth water flow conditions and non-smooth water flow conditions;

[0029] Step 102: If the water flow condition is a smooth water flow condition, a first control instruction is issued based on the controller to set a wave maker in the target water area, and based on the water flow speed measuring device, the water flow speed of the target water area after the wave is made is measured; the wave maker is used to make waves of a set height in the speed measuring area of ​​the water flow speed measuring device;

[0030] Step 103: If the water flow condition is a non-smooth water flow condition, the water flow speed is measured in the target water area based on the water flow speed measuring equipment.

[0031] In some embodiments, based on the first control instruction issued by the controller, a wave maker is set in the target water area, and based on the water flow speed measuring device, the water flow speed of the target water area after the wave is made is measured, which specifically includes:

[0032] Step 201: Based on the radar speed measurement component (in this embodiment, the millimeter wave radar speed measurement component), the echo signal of the target area is obtained; the target area is the area where waves are made in the target water area by the wave maker under the condition of smooth water flow; the echo signal includes the time difference between the transmission and reception of the echo signal, the signal frequency offset caused by the Doppler effect, and the signal strength;

[0033] Step 202: filtering and denoising the echo signal to obtain a processed echo signal;

[0034] Step 203: extracting features from the processed echo signal to obtain frequency features, time domain features and waveform features of the processed echo signal; the frequency features are used to determine the surface velocity of the water flow in the target area; the time domain features are used to determine the distance from the radar speed measurement component to the water flow surface; the waveform features are used to determine the spray features of the target area; the spray features include the periodicity and asymmetry of the reflected wave of the spray;

[0035] Step 204: using the minimization of mean square error in the linear regression method to determine the best fitting line between the frequency feature, the time domain feature, the waveform feature and the flow velocity;

[0036] Step 205: Determine the water flow velocity in the target area according to the best fitting line.

[0037] In some embodiments, when executing step 201, the specific steps may be as follows:

[0038] When acquiring the echo signal of the target area based on the millimeter wave radar, this embodiment designs a "spray maker" structure, which can stimulate the water flow to produce certain fluctuations in a smooth water flow environment. Since the smooth water flow itself has a certain flow rate, the setting of the spray maker can break the mirror reflection of the water flow surface, stimulate local fluctuations, and form a spray structure that can reflect electromagnetic waves.

[0039] In some embodiments, when executing steps 202-205, the specific steps may be as follows:

[0040] This embodiment designs a wave velocity detection algorithm based on millimeter wave radar. The algorithm can process the echo signal received by the radar, identify and extract the signal features related to the waves, and calculate the true velocity of the water flow based on these features. By optimizing the signal processing method, the algorithm can effectively eliminate external interference, so that the error between the measurement result and the actual velocity of the water flow is smaller. The wave velocity detection algorithm based on millimeter wave radar is one of the core parts of this embodiment. Its design purpose is to accurately process the echo signal received by the millimeter wave radar, extract the characteristic information related to the waves on the water surface, and calculate the true velocity of the water flow based on these features. This algorithm can not only improve the measurement accuracy, but also effectively eliminate external interference to ensure that the results are more reliable and accurate.

[0041] First, under the condition that the wave maker creates waves, the millimeter wave radar transmits electromagnetic waves and receives the reflected echo signal. The echo signal contains three characteristics: the time difference from the wave signal transmission to the reception; the signal frequency offset caused by the Doppler effect, the offset size is related to the water surface flow rate; and the signal strength, which is related to the shape and size of the waves and the distance between the millimeter wave radar and the water surface.

[0042] The processing of echo signals is where the flow velocity detection algorithm is applied.

[0043] 1) Filter and denoise the echo signal. First, use low-pass filters and high-pass filters to remove the interference of low-frequency and high-frequency background noise, and then use band-pass filters to filter out the signals within the frequency range of interest.

[0044] 2) Extract the features of the signal. There are three features:

[0045] (1) Frequency characteristics: Use fast Fourier transform (FFT) to convert the time domain signal into a frequency domain signal, and calculate the difference between the transmitted wave signal frequency and the reflected wave signal frequency. According to the formula Calculate the surface velocity of the water flow. Where Δf is the frequency offset, v is the surface velocity of the water flow, and λ is the wavelength of the radar wave.

[0046] (2) Time domain characteristics: The shorter the time difference between the radar wave transmission and reception, the closer the millimeter wave radar is to the water surface. The matched filter method is used to calculate the distance from the radar to the water surface. Let the transmission signal be s(t) and the echo signal be s r (t), the matched filter is h r (t) = s * (-t), convolve the echo signal and the matched filter, and we have:

[0047] s o (t) = s r (t)*h r (t)=s(t)*s * (-t)*h(t);

[0048] Perform Fourier transform on the above formula:

[0049] S o (jw) = S(jw)S * (jw)H(jw)=|S(jw)| 2 H(jw);

[0050] Among them, S o (jw) is s o (t), S(jw) is the Fourier transform of s(t), and H(jw) is the Fourier transform of h(t);

[0051] For the transmitted signal s(t), its amplitude-frequency characteristic is a constant k, which can be rewritten as:

[0052] S o (jw) = kH(jw);

[0053] The inverse Fourier transform is:

[0054] s o (t) = kh(t) = kσδ(t-τ);

[0055] Where σ is the scattering characteristic of the water surface, and τ is the time it takes for light to travel between the radar and the water surface.

[0056] The relationship between the water surface distance R and τ is:

[0057]

[0058] In the formula, R is the distance from the radar to the water surface, and c is the speed of light.

[0059] (3) Waveform characteristics: Use the shape, amplitude and other information of the echo signal to analyze the characteristics of the waves. The reflected waves of waves are usually periodic and asymmetric. The waveform of the signal can help identify the characteristics related to the flow velocity. The relationship between the signal waveform and the flow velocity is described by the average amplitude, periodicity and symmetry of the signal. Generally speaking, the larger the waves, the stronger the echo signal amplitude, and the more obvious the periodicity and symmetry.

[0060] The average amplitude of the echo signal is:

[0061] A=aver(|s r (t)|).

[0062] The periodic quantification uses the autocorrelation function of the signal as:

[0063]

[0064] The most common method to quantify periodicity is to use the autocorrelation function. Periodicity information can be obtained by calculating the similarity between the signal and itself at different time delays. The peak of the autocorrelation function occurs at the periodic position of the signal. Skewness and kurtosis are used to quantify the symmetry of the signal. Skewness is an important statistic to measure the asymmetry of the signal. It measures the degree to which the distribution of the signal is offset from its mean. Skewness definition:

[0065]

[0066] Kurtosis is a statistic that describes the steepness of the signal peak and reflects the sharpness of the waveform. Kurtosis definition:

[0067]

[0068] Where μ is the mean of the signal and σ is the standard deviation.

[0069] Finally, the Doppler frequency and waveform features are combined. Since the flow velocity has a linear relationship with these features, linear regression is used to fit the relationship between the features and the flow velocity:

[0070] v o =aΔf+bA+cη+dγ 1 +edγ 2 ;

[0071] Among them, Δf is the frequency offset, A is the average amplitude of the echo signal, η is the autocorrelation function of the periodic quantization signal, γ 1 is the deviation of the echo signal distribution relative to its mean, γ 2 is the kurtosis of the echo signal, and a, b, c, d, and e are the coefficients of each feature fitted in the linear regression method.

[0072] Linear regression finds the best fit line by minimizing the mean squared error:

[0073]

[0074] Among them, v o represents the measured flow rate, v i Represents the actual flow rate.

[0075] Through linear regression, the relationship between characteristics and flow rate can be quantified and ultimately flow rate measurement can be achieved.

[0076] Embodiment 2

[0077] like Figure 2 As shown, this embodiment provides a water flow speed measuring device, including: a wave maker, a radar speed measuring component and a processor;

[0078] The wave maker comprises a water flow impact surface, a fixing hole and an adjusting bracket; the water flow impact surface is arranged in the direction of the water flow, and is used to make local water flows impact each other to generate irregular waves and waves; the adjusting bracket is used to adjust the angle and height of the water flow impact surface according to the water depth of the target water area; the fixing hole is used to fix the wave maker at a preset position;

[0079] The radar speed measuring component is arranged downstream of the water flow impact surface, and is used to transmit radar signals to the target area and receive echo signals; the target area is the area where waves are made in the target water area by the wave maker under smooth water flow conditions;

[0080] The processor is connected to the radar speed measurement component and is used to calculate the water flow velocity according to the received echo signal.

[0081] Wherein, the radar speed measurement component is a millimeter wave radar speed measurement component.

[0082] In this embodiment, the core function of the wave maker is to break the smooth state of the water flow by physical means, so as to generate fluctuations, turbulence or waves on the water surface, thereby providing a usable reflection target for the millimeter wave radar. The principle of generating waves in smooth water flow mainly depends on the disturbance of the water flow by the mechanical device.

[0083] The wave maker is made of corrosion-resistant materials such as stainless steel and engineering plastics to prevent oxidation corrosion caused by long-term exposure to water flow. The size of the wave maker should be 1 / 8 to 1 / 10 of the pipe diameter. If the size of the wave maker is too small, the effect of making waves is not obvious; if the size is too large, it is difficult to accurately adjust the size of the waves, and it is more likely to cause pipe blockage.

[0084] The mechanical structure of the wave maker is as follows Figure 3 and Figure 6 As shown, it has fixing holes to fix it at the bottom of the pipe. The three circular holes in the figure are the fixing holes. It has an adjustment bracket to adjust the angle, height, width and narrowness of the wave maker. The water flow impact surface is where the waves are generated. The water flow hitting this surface will directly generate waves. At the same time, the direction of the water flow is slightly changed, causing the water flow to impact each other behind the wave maker to generate waves again. This is the principle of the wave maker making waves. Among them, such as Figure 4-Figure 5As shown in the figure, a gasket is also provided at the bottom of the wave maker, which is fixed to the bottom of the pipe through the fixing holes on the gasket to ensure that the wave maker can operate stably even underwater. The material of the gasket is also corrosion-resistant to avoid corrosion problems caused by long-term underwater operations. The design of the gasket not only enhances the stability of the wave maker, but also can fine-tune the relative position of the wave maker and the water surface by adjusting the thickness of the gasket, further optimizing the wave making effect.

[0085] The wave maker is fixedly installed at the bottom of the pipe (generally used in the city's drainage and sewage pipes, as drainage and sewage pipes), and guides the water flow through the water flow impact plate connected to its upper part, so that the local water flow impacts each other to produce irregular fluctuations and waves. The wave maker can adjust the inclination angle, size, and height of the water flow impact plate to control the size of the waves. Generally speaking, when the water flow impact plate is not obviously above the water surface, the larger the inclination angle, the larger the size, and the higher the height, the larger the waves it produces. If the water flow impact plate is obviously above the water surface, adjusting the water flow impact plate in a larger direction will have no obvious effect on the generation of waves. Under normal circumstances, the highest point of the water flow impact plate should be adjusted to be flush with the water surface. The water flow impact plate cannot be parallel to the water surface. In this case, the water surface cannot effectively collide with the water flow impact plate, so that waves cannot be effectively generated.

[0086] When the radar waves reach these ripples or water splashes, they are scattered and reflected back from these ripples. The surface structure of these ripples and water splashes is more complex than that of a smooth water surface, with multiple reflection points, allowing the radar to receive sufficient reflected signals. At the same time, millimeter-wave radar can detect reflected waves of different frequencies. The frequency changes of these reflected waves are related to the speed of the water flow, so the flow speed can be inferred through the Doppler effect. When the waves are formed and begin to fluctuate, the radar can effectively calculate the speed of the water flow through the frequency deviation changes in the received echo signal.

[0087] Specifically, the wave maker breaks the mirror reflection characteristics of the smooth water flow, making the water surface no longer smooth, with sufficient roughness and irregularity, so that the electromagnetic waves can be reflected and scattered, significantly increasing the intensity of the reflected signal, and providing sufficient reflected signals for the millimeter-wave radar. This effect solves the problem that the millimeter-wave radar cannot detect the flow rate in the smooth water flow, and is a key technology for the application of millimeter-wave radar under the conditions of gentle water flow. The key point is that the wave maker not only breaks the smooth surface of the water surface, but also controls the size of the waves generated so that the millimeter-wave radar can accurately calculate the flow rate of the water flow through the echo signal. The wave maker can adjust the intensity of the water surface fluctuation as needed, so that it can generate sufficient reflection signals without being too violent to affect the stability and measurement accuracy of the radar signal.

[0088] The schematic diagram of the installation position of the wave maker is as follows: Figure 2 As shown. The radar installation angle is β, the radar beam angle is γ, its detection area is a cone, and the angle range of the beam is β±γ. The effective detection area of ​​the radar will cover this angle range. Therefore, the position of the wave maker needs to ensure that it is not located in this range (ie, the target area) to prevent the wave maker from interfering with the normal operation of the radar, but the wave maker can be set at the edge of the effective detection area. The angle between the wave maker and the vertical direction of the radar installation position should be greater than β+γ to ensure that the radar detection area is located in the area where the wave maker generates waves. The position constraint formula for the installation position of the wave maker is specifically as follows:

[0089] s 1 =ah·tan(β+γ)+s 2 ;

[0090] where s 1 is the horizontal distance from the wave maker to the millimeter wave radar, ah is the distance from the millimeter wave radar to the surface of the water flow, β is the radar installation angle, γ is the radar beam angle, and s 2 It is the horizontal distance from the wave maker to the incident point of the electromagnetic wave emitted by the millimeter-wave radar on the water surface.

[0091] Among them, s 2 =15cm; we get:

[0092] That is, the vertical angle θ between the wave maker and the millimeter wave radar installation location is:

[0093]

[0094] After testing, in the sewage and drainage pipes of the city, the wave maker is generally placed about 15cm in front of the incident point of the electromagnetic wave emitted by the millimeter-wave radar on the water surface (away from the millimeter-wave radar), and the water flow impact plate is adjusted to produce 2-5mm waves on the flat water surface. If the wave size is too small, it is still difficult for the water surface to produce enough reflected waves; if the wave size is too large, the reflected wave will be too intense, which may cause saturation distortion of the millimeter-wave radar receiving signal. At the same time, the electromagnetic wave scattering in space is too complicated, which will cause the measurement error of the millimeter-wave radar to become larger and the measurement accuracy to decrease.

[0095] In summary, this application has the following technical effects:

[0096] The present application provides an innovative method and mechanical structure capable of performing millimeter-wave radar velocity measurement under smooth water flow conditions. By designing a wave maker to break the mirror reflection problem on the water flow surface and combining an intelligent algorithm to accurately detect the flow velocity, the millimeter-wave radar can effectively receive the reflected echo, thereby improving the accuracy of the flow velocity measurement. At the same time, the use of a non-contact measurement method avoids equipment damage or water flow disturbance problems that may be caused by traditional methods, making the measurement safer and more reliable. The present application is suitable for flow velocity measurement under various water flow conditions, and can automatically complete the detection of water flow velocity without manual intervention. It is easy to operate and highly efficient. In particular, it has a large application advantage under smooth water flow conditions, and can provide efficient and accurate flow velocity detection solutions for fields such as water conservancy and environmental monitoring.

[0097] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0098] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for measuring water flow velocity, characterized in that: include: Obtain the water flow conditions of the target water area; The water flow conditions include smooth water flow conditions and non-smooth water flow conditions; If the water flow condition is a smooth water flow condition, a first control instruction is issued based on the controller, a wave maker is set in the target water area, and the water flow velocity is measured in the target water area after the wave is made based on the water flow velocity measuring device; the wave maker is used to make waves of a set height in the velocity measuring area of ​​the water flow velocity measuring device; If the water flow condition is a non-smooth water flow condition, the water flow speed is measured in the target water area based on the water flow speed measuring equipment.

2. A method for measuring water flow velocity according to claim 1, characterized in that: The water flow velocity measuring device comprises a radar velocity measuring component.

3. A method for measuring water flow velocity according to claim 1, characterized in that: Based on the first control instruction issued by the controller, a wave maker is set in the target water area, and based on the water flow speed measuring device, the water flow speed of the target water area after the wave is made is measured, which specifically includes: Based on the radar speed measurement component, an echo signal of a target area is obtained; the target area is an area where waves are made in the target water area by a wave maker under smooth water flow conditions; the echo signal includes a time difference between the transmission and reception of the echo signal, a signal frequency offset caused by the Doppler effect, and a signal strength; Performing filtering and denoising on the echo signal to obtain a processed echo signal; Extracting features of the processed echo signal to obtain frequency features, time domain features and waveform features of the processed echo signal; the frequency features are used to determine the surface velocity of the water flow in the target area; the time domain features are used to determine the distance from the radar speed measuring component to the water flow surface; the waveform features are used to determine the spray features of the target area; the spray features include the periodicity and asymmetry of the reflected wave of the spray; Using the minimization of mean square error in the linear regression method, the best fitting line between the frequency characteristic, the time domain characteristic, the waveform characteristic and the flow velocity is determined; Based on the best fit line, determine the water flow velocity in the target area.

4. A method for measuring water flow velocity according to claim 3, characterized in that: The target area is the effective detection area of ​​the radar speed measurement component, and the wave maker is arranged at the edge of the effective detection area and is not within the effective detection area.

5. A method for measuring water flow velocity according to claim 3, characterized in that: Minimizing the mean square error in the linear regression method is used to determine the best fitting line between the frequency feature, the time domain feature, the waveform feature and the flow velocity, specifically including: According to the formula Determine a best fit line between the frequency characteristic, the time domain characteristic, the waveform characteristic and the flow velocity; Among them, v o To measure flow velocity, v i is the actual flow rate, and n is the number of samples.

6. A method for measuring water flow velocity according to claim 5, characterized in that: The calculation formula for the measured flow rate is: v o =aΔf+bA+cη+dγ1+edγ2; Among them, Δf is the frequency offset, A is the average amplitude of the echo signal, η is the autocorrelation function of the periodic quantization signal, γ1 is the degree of deviation of the echo signal distribution relative to its mean, γ2 is the kurtosis of the echo signal, and a, b, c, d, and e are the coefficients of each feature fitted in the linear regression method.

7. A method for measuring water flow velocity according to claim 5, characterized in that: The actual flow rate is calculated as: Where Δf is the frequency offset, v is the surface velocity of the water flow, and λ is the wavelength of the radar wave.

8. A method for measuring water flow velocity according to claim 7, characterized in that: The distance from the radar speed measuring component to the water surface is calculated as follows: According to the formula o (t) = s r (t)*h r (t)=s(t)*s * (-t)*h(t), convolve the echo signal and the matched filter; where s(t) is the signal emitted by the radar speed measurement component, s r (t) is the echo signal, and the matched filter is h r (t) = s * (-t); For formula s o (t) = s r (t)*h r (t)=s(t)*s * (-t)*h(t) is transformed by Fourier, and the formula S is obtained. o (jw) = kH(jw); where S o (jw) is s o (t), k is |S(jw)| 2 , S(jw) is the Fourier transform of s(t), H(jw) is the Fourier transform of h(t); For S o (jw) = kH(jw) and perform inverse Fourier transform to obtain the formula s o (t) = kh(t) = kσδ(t-τ); According to the formula Calculate the distance from the radar speed measuring component to the water surface; Among them, σ is the scattering characteristic of the water surface, and τ is the time it takes for light to travel between the radar and the water surface.

9. A water flow velocity measuring device, characterized in that: include: wave makers, radar speed measurement components and processors; The wave maker comprises a water flow impact surface, a fixing hole and an adjusting bracket; the water flow impact surface is arranged in the direction of the water flow, and is used to make local water flows impact each other to generate irregular waves and waves; the adjusting bracket is used to adjust the angle and height of the water flow impact surface according to the water depth of the target water area; the fixing hole is used to fix the wave maker at a preset position; The radar speed measuring component is arranged downstream of the water flow impact surface, and is used to transmit radar signals to the target area and receive echo signals; the target area is the area where waves are made in the target water area by the wave maker under smooth water flow conditions; The processor is connected to the radar speed measurement component and is used to calculate the water flow velocity according to the received echo signal.

10. A water flow velocity measuring device according to claim 9, characterized in that: The radar speed measurement component is a millimeter wave radar speed measurement component.

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