A two-way high-precision water body detection method and circuit

Abstract

The present invention provides a bidirectional high-precision water body detection method, including: transmitting a detection signal to the water body to be detected and acquiring the reflected signal of the water body to be detected; mixing the reflected signal with a low-frequency wave of a first frequency to generate a first signal; calculating the water body flow direction based on the first signal; at the same time, mixing the reflected signal with a high-frequency wave of a second frequency to generate a second signal; calculating the water body flow velocity based on the second signal; and determining the water body detection result according to the water body flow direction and the water body flow velocity. By dividing the reflected signal into two paths to calculate the flow direction and flow velocity of the measured water body respectively, the present invention ensures the accuracy of both the water body flow direction and the flow velocity in water body detection.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of sensors, and in particular, to a bidirectional high-precision water body detection method and circuit. Background Art

[0002] With the acceleration of the urbanization process, the length of urban drainage pipe networks has increased rapidly, and the impact of rainwater and sewage discharge on the urban water environment has become increasingly serious. Accurately measuring the water body flow velocity is of great significance for rainwater and sewage discharge control, water volume and quality scheduling of sewage treatment plants, pipe network hydrodynamic simulation, flood simulation and forecasting. Since the drainage pipes are in harsh working conditions such as non-full pipes, high turbidity, pipe bottom siltation, a lot of oil pollution and floating objects on the water surface, and flammable / explosive gases filling, the measurement of water body flow velocity and direction has always been a technical difficulty.

[0003] In traditional Doppler acoustic flow meters, generally the mixing frequency is selected at a low frequency to obtain a low-frequency signal for the water body flow velocity. However, due to the lack of negative information, it is not easy to obtain the water body flow direction information. Although the signal obtained by using high-frequency mixing has direction information, its spectrum is compressed in a small range, and its accuracy and sensitivity are poor, which easily leads to a reduction in the accuracy of judging the flow velocity and cannot ensure good measurement effects for both accuracy and flow velocity simultaneously. Summary of the Invention

[0004] The present invention provides a bidirectional high-precision water body detection method and circuit. The reflected signal is used to measure the flow direction and flow velocity of the water body respectively, so that the water body detection can achieve simultaneous high-precision detection of the flow direction and flow velocity, improving the accuracy.

[0005] In a first aspect, the present invention provides a bidirectional high-precision water body detection method, including:

[0006] Transmitting a detection signal to the water body to be detected and obtaining the reflected signal of the water body to be detected;

[0007] Mixing the reflected signal with a low-frequency wave of a first frequency to generate a first signal;

[0008] Calculating the water body flow direction based on the first signal;

[0009] Meanwhile, mixing the reflected signal with a high-frequency wave of a second frequency to generate a second signal;

[0010] Calculating the water body flow velocity based on the second signal;

[0011] Determining the water body detection result according to the water body flow direction and the water body flow velocity.

[0012] Further, the calculating the water body flow direction based on the first signal includes:

[0013] Calculating the third frequency of the first signal;

[0014] Determine whether the third frequency is greater than a preset threshold;

[0015] If it is greater, determine that the water body flow direction is the positive direction;

[0016] If it is less, determine that the water body flow direction is the negative direction.

[0017] Further, calculating the third frequency of the first signal includes:

[0018] Input the first signal into a filter for filtering to output a third signal;

[0019] Sample the third signal based on a preset sampling frequency to obtain a sampled signal;

[0020] Perform a Fourier transform on the sampled signal, and determine the third frequency based on the energy intensity of the transformed fourth signal.

[0021] Further, calculating the water body flow velocity based on the second signal includes:

[0022] Input the second signal into a filter for filtering to output a fourth signal;

[0023] Perform a Fourier transform on the fourth signal, and determine the fourth frequency based on the energy intensity of the transformed fourth signal;

[0024] Calculate a frequency offset value based on the fourth frequency;

[0025] Calculate the water body flow velocity based on the frequency offset value.

[0026] Further, after emitting a detection signal to the water body to be detected and obtaining the reflected signal of the water body to be detected, it further includes: amplifying the reflected signal.

[0027] In a second aspect, the present invention provides a two-way high-precision water body detection circuit, including: a receiving module, a water body flow direction determination module, a water body flow velocity determination module, and an output module;

[0028] The receiving module is used to emit a detection signal to the water body to be detected and obtain the reflected signal of the water body to be detected;

[0029] The water body flow direction determination module is used to mix the reflected signal with a low-frequency wave of the first frequency to generate a first signal, and calculate the water body flow direction based on the first signal;

[0030] The water body flow velocity determination module is used to mix the reflected signal with a high-frequency wave of the second frequency to generate a second signal, and calculate the water body flow velocity based on the second signal;

[0031] An output module, configured to determine a water body detection result according to the water body flow direction and the water body flow velocity.

[0032] Further, the water body flow direction determination module is further configured to calculate a third frequency of the first signal; determine whether the first frequency is greater than a preset threshold; if it is greater, determine that the water body flow direction is the positive direction; if it is less, determine that the water body flow direction is the negative direction.

[0033] Further, the water body flow direction determination module is specifically configured to:

[0034] Input the first signal into a filter for filtering to output a third signal;

[0035] Sample the third signal based on a preset sampling frequency to obtain a sampled signal;

[0036] Perform a Fourier transform on the sampled signal, and determine the third frequency based on the energy intensity of the transformed fourth signal.

[0037] Further, the water body flow velocity determination module is further configured to: input the second signal into a filter, and output it as a fourth signal; generate a second frequency through Fourier transform of the fourth signal; calculate the water body flow velocity through the second frequency.

[0038] Further, it further includes: a signal amplification module, configured to amplify the reflection signal.

[0039] In the present invention, the flow velocity and flow rate are collected in different frequency bands respectively. By dividing the collected signals into a direction collection part and a flow velocity collection part, since the final center frequency of the direction collection is relatively high, some flow velocities are compressed in a narrow frequency band range, which is easy to achieve high-precision collection of flow velocity details. At the same time, the other path uses mixing to determine the flow velocity to ensure the accuracy of both the water body flow direction and the flow velocity. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] As Figure 1 shown is the flowchart of the two-way high-precision water body detection method in the first embodiment.

[0041] As Figure 2 shown is the flowchart of the two-way high-precision water body detection method in the second embodiment.

[0042] As Figure 3 shown is the circuit module diagram in the third embodiment.

[0043] As Figure 4 shown is the circuit module diagram of the alternative embodiment in the third embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the present invention, rather than limiting the present invention. In addition, it should be noted that, for the sake of description, only the parts related to the present invention are shown in the drawings, rather than all the structures.

[0045] Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts depict the steps as sequential processes, many of the steps can be implemented in parallel, concurrently, or simultaneously. In addition, the order of the steps can be rearranged. The process can be terminated when its operations are completed, but it can also have additional steps not included in the drawings. The process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0046] In addition, terms such as "first", "second", etc. may be used herein to describe various directions, actions, steps, or elements, etc., but these directions, actions, steps, or elements are not limited by these terms. These terms are only used to distinguish the first direction, action, step, or element from another direction, action, step, or element. For example, without departing from the scope of the present application, the first feature information may be the second feature information or the third feature information. Similarly, the second feature information and the third feature information may be the first feature information. The first feature information, the second feature information, and the third feature information are all feature information of the distributed file system, but they are not the same feature information. The terms "first", "second", etc. should not be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, the meanings of "a plurality" and "batch" are at least two, such as two, three, etc., unless otherwise specifically defined.

[0047] Embodiment 1

[0048] This embodiment provides a two-way high-precision water body detection method, which is executed by a two-way high-precision water body detection circuit provided in a Doppler ultrasonic current meter. The current meter is arranged in the water body channel to be detected, and the orientation is kept parallel to the water flow direction. As Figure 1 shown, the method includes the following steps:

[0049] S101. Transmit a detection signal to the water body to be detected and obtain the reflected signal of the water body to be detected.

[0050] In this step, the detection signal is an ultrasonic signal or an electrical signal of a fixed frequency. Correspondingly, the reflected signal is an ultrasonic signal or an electrical signal. Exemplarily, the ultrasonic transducer converts the electrical signal of the transmitting circuit into an ultrasonic signal and transmits it. The ultrasonic wave is reflected by the suspended matter in the flowing water body to generate a reflected signal. The ultrasonic transducer converts the obtained ultrasonic signal into an electrical signal and enters the detection circuit for calculation to obtain the detection result. Specifically, the reflected signal is divided into two paths, and steps S102 and S104 are respectively executed.

[0051] In an alternative implementation, optionally, after this step, it further includes: amplifying the reflected signal. Optionally, the signal is amplified by a multi-stage amplifier circuit.

[0052] S102. Mix the reflected signal with a low-frequency wave of the first frequency to generate a first signal.

[0053] The mixing in this step is used to generate a low-frequency wave after mixing the reflected signal. This low-frequency wave is a signal point near a frequency of 0. The advantage of this signal is its wide frequency band and low interference, which is beneficial to testing and obtaining the actual flow direction. Exemplarily, the first frequency is 800 kHz.

[0054] S103. Calculate the water body flow direction based on the first signal.

[0055] The water body flow direction in this step is the positive direction or the negative direction. The positive direction refers to the water body flowing towards the ultrasonic current meter, and the negative direction refers to the water body flowing away from the ultrasonic current meter. In this step, a first signal is generated by mixing with a low-frequency wave of the first frequency. The first signal is filtered by a filter to remove interference, and the water body flow direction is judged based on the Doppler effect. Exemplarily, the reflected signal is mixed with a wave of 800 kHz to generate a first signal near 200 kHz.

[0056] The calculation method in this step calculates the water body flow direction through the Doppler effect. However, since frequency compression is only suitable for judging the water body flow direction, in the following step S104, another calculation method is used to calculate the flow velocity of the reflected signal to ensure that the detection results of both the flow direction and the flow velocity are accurate.

[0057] S104. At the same time, mix the reflected signal with a high-frequency wave of the second frequency to generate a second signal.

[0058] S105. Calculate the water body flow velocity based on the second signal.

[0059] In the above steps S104 - S105, the second frequency is 1Mhz, and the high - frequency wave of the second frequency is the clock signal generated by the circuit. Then, in this mixing process, the 1Mhz reflected signal is mixed with the 1Mhz clock signal to generate a second signal, and the generated signal is collected by the control chip and sampled to obtain the frequency and calculate the water flow velocity.

[0060] S106. Determine the water body detection result according to the water body flow direction and the water body flow velocity.

[0061] The water body detection result of this step is the water body flow velocity value with direction.

[0062] In this embodiment, by dividing the reflected signal into two paths, the collected signal is divided into a direction detection part and a flow velocity detection part. For water body flow direction detection, using low - frequency waves compresses the flow velocity information in a narrow frequency band range, which is likely to cause difficulties in collecting flow velocity details, so it is only used for direction judgment. At the same time, the other path of mixing is used to determine the flow velocity, achieving both ensuring the accuracy of flow direction detection and the accuracy of flow velocity detection.

[0063] Embodiment Two

[0064] On the basis of the above - mentioned embodiment, this embodiment provides a specific calculation process for water body flow direction and water body flow velocity. The embodiment is executed by a bidirectional high - precision water body detection circuit set in a Doppler ultrasonic flowmeter. The flowmeter is set in the water channel to be detected, and the orientation is kept basically parallel or at a certain angle with the water body flow direction. It includes:

[0065] S201. Transmit a detection signal to the water body to be detected and obtain the reflected signal of the water body to be detected.

[0066] S202. Mix the reflected signal with a low - frequency wave of the first frequency to generate a first signal.

[0067] S2031. Calculate the third frequency of the first signal.

[0068] Specifically, the process of calculating the third frequency is as follows: input the first signal into a filter for filtering to output a third signal; sample the third signal based on a preset sampling frequency to obtain a sampled signal; perform a Fourier transform on the sampled signal, and determine the third frequency based on the energy intensity of the transformed fourth signal.

[0069] Specifically, the first signal is mixed with an 800Khz wave to generate a 200Khz third signal. The third signal is input into a band - pass filter for filtering to remove interference. The third signal after removing interference is sampled by a controller with a preset frequency to obtain a sampled signal and perform a Fourier transform to generate an energy spectrum, and the third frequency is determined based on the energy spectrum.

[0070] S2032. Determine whether the third frequency is greater than a preset threshold.

[0071] S2033. If it is greater, determine that the water flow direction is the positive direction.

[0072] S2034. If it is less, determine that the water flow direction is the negative direction.

[0073] In the above steps S2033 - S2034, the positive direction means the water flows towards the direction close to the ultrasonic flowmeter, and the negative direction means the water flows towards the direction away from the ultrasonic flowmeter. According to the Doppler effect, when the water is away from the ultrasonic flowmeter, the third frequency will be less than the preset threshold, and when the water is close to the ultrasonic flowmeter, the third frequency will be greater than the preset threshold. Among them, the third frequency being equal to the preset threshold indicates that the water is not flowing.

[0074] Exemplarily, the preset threshold is set to 200Khz. When the third frequency is greater than 200khz, it is determined that the water flow direction is the positive direction. When the third frequency is less than 200khz, it is determined as the negative direction.

[0075] S204. At the same time, mix the reflected signal with the high-frequency wave of the second frequency to generate a second signal.

[0076] S2051. Input the second signal into a filter for filtering to output a fourth signal.

[0077] S2052. Perform Fourier transform on the fourth signal, and determine the fourth frequency based on the energy intensity of the transformed fourth signal.

[0078] S2053. Calculate a frequency deviation value based on the fourth frequency.

[0079] S2054. Calculate the water flow velocity based on the frequency deviation value.

[0080] In steps S2051 - S2054, the filter is a low-pass filter.

[0081] S206. Determine the water detection result according to the water flow direction and the water flow velocity.

[0082] This embodiment adds a description of the specific calculation process on the basis of the above embodiment, making the detection of the flow direction and accuracy more accurate.

[0083] Embodiment Three

[0084] This embodiment provides a bidirectional high-precision water detection circuit disposed inside a Doppler ultrasonic flowmeter, which calculates the received reflected signal to determine the water flow velocity and the water flow direction.

[0085] Such as Figure 3, the circuit in this embodiment includes: a receiving module 301, a water flow direction determination module 302, a water flow velocity determination module 303, and an output module 304.

[0086] The receiving module 301 is used to transmit a detection signal to the water body to be detected and obtain the reflected signal of the water body to be detected. Exemplarily, this module is a signal amplification circuit.

[0087] The water flow direction determination module 302 is used to mix the reflected signal with a low-frequency wave of the first frequency to generate a first signal, calculate the water flow direction based on the first signal; and is also used to calculate the third frequency of the first signal; determine whether the first frequency is greater than a preset threshold; if it is greater, it is determined that the water flow direction is the positive direction; if it is less, it is determined that the water flow direction is the negative direction.

[0088] The water flow velocity determination module 303 is also used to mix the reflected signal with a high-frequency wave of the second frequency to generate a second signal, calculate the water flow velocity based on the second signal; and is also used to input the second signal into a filter and output it as a fourth signal; generate the second frequency through Fourier transform of the fourth signal; and is used to calculate the water flow velocity through the second frequency.

[0089] The output module 304 is used to determine the water body detection result according to the water flow direction and the water flow velocity.

[0090] Such as Figure 4 , in an alternative embodiment, it further includes: a signal amplification module 305, which is used to amplify the reflected signal. Optionally, this module is a filter amplification circuit.

[0091] In this embodiment, by providing a two-way high-precision water body detection circuit, the reflected signal is divided into two paths to calculate the flow direction and flow velocity of the measured water body respectively, so as to ensure the accuracy of both the water flow direction and the flow velocity during water body detection.

[0092] Note that the above is only the preferred embodiment of the present invention and the applied technical principle. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described here. Various obvious changes, re-adjustments, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, it can also include more other equivalent embodiments, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A two-way high-precision water body detection method, characterized in that, Including: Transmitting a detection signal to the water body to be detected and obtaining the reflected signal of the water body to be detected; Mixing the reflected signal with a low-frequency wave of a first frequency to generate a first signal; Calculating the water body flow direction based on the first signal; Meanwhile, mixing the reflected signal with a high-frequency wave of a second frequency to generate a second signal; Calculating the water body flow velocity based on the second signal; Determining the water body detection result according to the water body flow direction and the water body flow velocity; The calculating the water body flow direction based on the first signal includes: Calculating the third frequency of the first signal; Judging whether the third frequency is greater than a preset threshold; If it is greater, determining that the water body flow direction is the positive direction; If it is less, determining that the water body flow direction is the negative direction; The calculating the water body flow velocity based on the second signal includes: Inputting the second signal into a filter for filtering to output a fourth signal; Performing a Fourier transform on the fourth signal and determining the fourth frequency based on the energy intensity of the transformed fourth signal; Calculating a frequency offset value based on the fourth frequency; Calculating the water body flow velocity based on the frequency offset value; The calculating the third frequency of the first signal includes: Inputting the first signal into a filter for filtering to output a third signal; Sampling the third signal based on a preset sampling frequency to obtain a sampling signal; Performing a Fourier transform on the sampling signal and determining the third frequency based on the energy intensity of the transformed third signal.

2. The bidirectional high-precision water body detection method according to claim 1, wherein After the transmitting a detection signal to the water body to be detected and obtaining the reflected signal of the water body to be detected, it further includes: amplifying the reflected signal.

3. A two-way high-precision water body detection circuit, characterized in that, Including: A receiving module, a water body flow direction determination module, a water body flow velocity determination module, and an output module; The receiving module is used to transmit a detection signal to the water body to be detected and obtain the reflected signal of the water body to be detected; The water body flow direction determination module is used to mix the reflected signal with a low-frequency wave of a first frequency to generate a first signal and calculate the water body flow direction based on the first signal; The water body flow velocity determination module is used to mix the reflected signal with a high-frequency wave of a second frequency to generate a second signal and calculate the water body flow velocity based on the second signal; The output module is used to determine the water body detection result according to the water body flow direction and the water body flow velocity; The water body flow direction determination module is further used for: Calculating the third frequency of the first signal; Judging whether the third frequency is greater than a preset threshold; If it is greater, determining that the water body flow direction is the positive direction; If it is less, determining that the water body flow direction is the negative direction; The water body flow velocity determination module is further used for: Inputting the second signal into a filter for filtering to output a fourth signal; Performing a Fourier transform on the fourth signal and determining the fourth frequency based on the energy intensity of the transformed fourth signal; Calculating a frequency offset value based on the fourth frequency; Calculating the water body flow velocity based on the frequency offset value; The water body flow direction determination module is specifically used for: Inputting the first signal into a filter for filtering to output a third signal; Sampling the third signal based on a preset sampling frequency to obtain a sampling signal; Perform a Fourier transform on the sampled signal, and determine the third frequency based on the energy intensity of the transformed third signal.

4. A two-way high-precision water body detection circuit according to claim 3, characterized in that, It further includes: A signal amplification module for amplifying the reflected signal.

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