Radar flowmeter with environment compensation and compensation method

Abstract

The invention provides a radar flowmeter with environment compensation and a compensation method, and relates to the technical field of measurement, the radar flowmeter comprises an environment compensation module and a monitoring module; the environment compensation module is arranged on the upper shell and is used for monitoring rainfall and wind speed; the monitoring module is arranged on the lower shell and used for monitoring the water level and the flow. The upper shell and the lower shell are fastened through bolts. The compensation method comprises the steps of obtaining a rainfall signal and a humidity value; judging whether the current environment is rainfall or local dripping based on the rainfall signal and the humidity value; and when it is judged that rainfall exists, the section flow of the river channel is dynamically compensated. According to the radar flowmeter with the environment compensation function and the compensation method, high-precision and real-time water flow monitoring can still be achieved under the complex weather conditions such as rainfall and strong wind, and the radar flowmeter with the environment compensation function and the compensation method have remarkable technical advantages and application prospects.

Description

Technical Field

[0001] The present invention relates to the field of measurement technology, and particularly to a radar flowmeter with environmental compensation and a compensation method. Background Art

[0002] The statements in this section merely provide background art related to the present disclosure and do not necessarily constitute prior art.

[0003] Rainfall and wind speed are important environmental factors affecting the performance of radar flow measurement systems. During rainfall, raindrops cause attenuation of radar waves, weakening the penetration and intensity of signals, and thus affecting the measurement depth and accuracy. At the same time, phenomena such as ring waves and crown-shaped water columns generated by raindrops hitting the water surface increase the roughness of the water surface, affect the echo characteristics of radar waves, and reduce the reflection accuracy of water ripples. In addition, under strong wind weather, changes in wind speed and direction cause attenuation and scattering of radar signals. This effect is more significant in open areas or regions with higher wind speeds. Therefore, radar flowmeters need to have the ability to cope with adverse weather conditions to ensure high-precision and real-time water flow monitoring under complex weather conditions such as rainfall and strong winds.

[0004] In the prior art, only the influence of wind speed and direction on water flow monitoring is considered. Taking the utility model patent with the authorization announcement number CN220772267U as an example, this utility model discloses a radar flowmeter with wind speed monitoring, which cancels and smooths the influence of wind speed on the water surface flow velocity to give a relatively accurate actual flow velocity, and does not involve compensation for the interference of precipitation on radar wave signals. At the same time, this utility model directly installs the ultrasonic wind speed probe on the upper shell lower cover, and the wind speed probe is exposed to the environment. During rainy or snowy weather, raindrops or snowflakes cause attenuation of ultrasonic waves, resulting in inaccurate wind speed measured by the ultrasonic wind speed probe. In addition, the ultrasonic wind speed probe is directly installed on the upper shell lower cover, and in the actual wind speed measurement scenario, it cannot cover enough measurement areas, and can only measure the wind speed in a certain direction. The wind speed component in the orthogonal direction cannot be accurately captured and cannot be calculated to obtain the total wind speed and wind direction angle. Summary of the Invention

[0005] To solve the above problems, the present invention provides a radar flowmeter with environmental compensation and a compensation method. By setting a rain and snow monitoring sensor and an air temperature and humidity monitoring sensor, the precipitation situation in the environment is monitored in real time. After the rain and snow monitoring sensor identifies precipitation, combined with the data of the air temperature and humidity monitoring sensor, it is determined whether it is precipitation or local dripping in the current environment. Further, based on the air humidity measured by the air temperature and humidity monitoring sensor,

[0006] The first aspect of the present invention provides a radar flowmeter with environmental compensation, comprising: an environmental compensation module and a monitoring module; the environmental compensation module is arranged on the upper housing (1) for precipitation and wind speed monitoring; the monitoring module is arranged on the lower housing (2) for water level and flow monitoring; the upper housing and the lower housing are fastened by bolts;

[0007] The environmental compensation module includes: a rain and snow monitoring sensor (6) and an air temperature and humidity monitoring sensor (12); the rain and snow monitoring sensor (6) is installed on the upper surface of the upper housing for precipitation monitoring; the air temperature and humidity monitoring sensor (12) is installed inside the upper housing for environmental humidity monitoring;

[0008] The monitoring module includes: a water level radio frequency radar and a flow velocity radio frequency radar; the water level radio frequency radar is fixed on the water level measurement cover plate (3) at the flat end of the lower housing; the flow velocity radio frequency radar is fixed on the flow velocity measurement cover plate (4) at the inclined end of the lower housing.

[0009] Further, the upper housing and the lower housing being fastened by bolts includes:

[0010] A plurality of first threaded holes (8) are provided on the upper surface of the upper housing, and a corresponding plurality of second threaded holes (9) are provided on the upper surface of the lower housing, and the positions of the first threaded holes and the second threaded holes correspond one by one;

[0011] Each first threaded hole and the corresponding second threaded hole are fixed one by one through bolts.

[0012] Further, grid ventilation holes (7) are also provided around the upper housing for internal and external air circulation;

[0013] An ultrasonic transducer (13) is provided on one side of the grid ventilation holes (7), and the included angle between the central axis of the ultrasonic transducer and the plane of the grid ventilation holes ranges from 30° to 60°, and the ultrasonic transducer is used for measuring the environmental wind speed and wind direction.

[0014] Further, a control module is further included, and the control module includes a main board (11), and the main board (11) is installed inside the upper housing and is electrically connected to the rain and snow monitoring sensor (6), the air temperature and humidity monitoring sensor (12), the ultrasonic transducer (13), the water level radio frequency radar and the flow velocity radio frequency radar respectively for data processing and signal compensation.

[0015] Further, a third threaded hole (10) is also provided on the upper surface of the upper housing (1) for installing an orientation adjustment joint to adjust the orientation of the device.

[0016] The second aspect of the present invention provides a compensation method using the above-mentioned radar flowmeter with environmental compensation, and the compensation method includes:

[0017] S101: Obtain the precipitation signal of the rain and snow monitoring sensor (6) and the humidity value of the air temperature and humidity monitoring sensor (12);

[0018] S102: Based on the precipitation signal and the humidity value, judge whether the current environment is precipitation or local dripping through the following logic: If the humidity value ≥ RH0 and the temperature dew point difference ≤ T0, it is determined as precipitation; if the humidity value < RH0 and a precipitation signal is detected, it is determined as local dripping; where, RH0 is the humidity threshold and T0 is the temperature dew point difference threshold;

[0019] S103: When it is determined as precipitation, dynamically compensate the cross-sectional flow of the river channel to obtain the compensated cross-sectional flow; when it is determined as local dripping, there is no need to dynamically compensate the cross-sectional flow of the river channel.

[0020] Further, in step S103: When it is determined as precipitation, dynamically compensate the cross-sectional flow of the river channel. The dynamic compensation calculation formula for the cross-sectional flow is:

[0021] Q = k * v * A

[0022] In the formula, Q: the compensated cross-sectional flow; v: the surface flow velocity; A: the cross-sectional area of the water flow; k: the correction coefficient.

[0023] Further, the calculation formula for the correction coefficient k is:

[0024]

[0025] Among them, RH is the air humidity, P is the rainfall, V 风 is the wind speed, α is the air humidity coefficient obtained by simulating the on-site air humidity in the laboratory, β is the rainfall coefficient obtained by simulating the on-site rainfall in the laboratory, and γ is the wind speed coefficient obtained by simulating the on-site wind speed in the laboratory.

[0026] Further, the surface flow velocity is calculated according to the Doppler effect formula. The corresponding relationship between the frequency and the surface flow velocity in the Doppler effect is:

[0027]

[0028] Among them, f d is the current frequency value, v is the surface flow velocity, and α is the installation angle between the radar flowmeter and the water surface.

[0029] Further, the calculation method for the wind speed V 风 includes:

[0030] S104: Calculate the wind speed in the east-west direction,

[0031] Among them, is the east-west wind speed component, and t1 is the east-west downwind propagation time. t2 is the east-west upwind propagation time. L x is the distance between ultrasonic transducers in the east-west direction, and v x is the east-west wind speed measured by the ultrasonic transducer, and c is the speed of sound.

[0032] S105: Calculate the north-south wind speed.

[0033] Among them, is the east-west wind speed component, t3 is the east-west downwind propagation time, and t4 is the east-west upwind propagation time. L y is the distance between ultrasonic transducers in the east-west direction, and v y is the north-south wind speed measured by the ultrasonic transducer, and c is the speed of sound.

[0034] S106: Synthesize the total wind speed and wind direction angle. V 风 is the total wind speed. The wind direction angle takes the due north as 0°, and rotates clockwise. δ is the angle correction value.

[0035] Compared with the prior art, a radar flowmeter with environmental compensation and a compensation method provided by the present invention have the following beneficial effects:

[0036] (1) The radar flowmeter provided by the present invention integrates components such as rain and snow monitoring sensors, air temperature and humidity monitoring sensors, and ultrasonic transducers to real-time monitor meteorological conditions such as precipitation (rainfall, snowfall), wind speed, and wind direction in the environment, and combines the air humidity in the environment to accurately identify precipitation conditions, avoid misjudging local dripping as precipitation, realize real-time compensation for the interference of radar wave signals by environmental factors, and improve the measurement accuracy and stability of the radar flowmeter under complex weather conditions.

[0037] (2) The compensation method provided by the present invention determines the current environmental state through logical judgment according to the precipitation signal and humidity value. When it is confirmed as precipitation, compensation calculation is performed on the sectional flow. Specifically, the present invention adopts a dynamic sectional flow compensation formula, and dynamically adjusts the correction coefficient according to parameters such as real-time monitored environmental humidity, rainfall, and wind speed, so as to ensure the accuracy of the measurement result. This dynamic compensation mechanism effectively addresses problems such as the attenuation of radar wave signals caused by rainfall and the increase in water surface roughness, as well as the influence of wind speed and wind direction changes on radar signals under strong wind weather.

[0038] (3) The present invention further improves the measurement accuracy by precisely calculating the surface flow velocity. The calculation of the surface flow velocity is based on the Doppler effect formula. By measuring the installation angle between the radar flowmeter and the water surface and the current frequency value, the surface flow velocity can be accurately obtained, providing reliable data support for the calculation of the cross-sectional flow rate.

[0039] (4) In terms of wind speed measurement, the present invention optimizes the angle (30° - 60°) between the central axis of the ultrasonic transducer and the plane of the grid ventilation holes to ensure that the ultrasonic signal covers a sufficient measurement area and avoid missing wind speed components and blind spots in the measurement. Further, the present invention measures the wind speed components in the east-west and north-south directions through the ultrasonic transducer, and then synthesizes the total wind speed and the wind direction angle, improving the accuracy of wind speed measurement and helping to more comprehensively understand the impact of the environment on the radar flow measurement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings forming a part of this disclosure are used to provide a further understanding of the disclosure. The illustrative embodiments and descriptions thereof of the disclosure are used to explain the disclosure and do not constitute an improper limitation of the disclosure.

[0041] Figure 1 An exploded view of the radar flowmeter with environmental compensation provided by the present invention;

[0042] Figure 2 A bottom view of the environmental compensation module of the radar flowmeter provided by the present invention;

[0043] Figure 3 A three-dimensional effect diagram of the radar flowmeter with environmental compensation provided by the present invention;

[0044] Figure 4 A flowchart of the environmental compensation method provided by the present invention;

[0045] Figure 5 A flowchart of an environmental compensation method provided in the second embodiment of the present invention.

[0046] In the figures: 1, upper housing; 2, lower housing; 3, water level measurement cover plate; 4, flow velocity measurement cover plate; 5, cylindrical hole; 6, rain and snow monitoring sensor; 7, grid ventilation hole; 8, first threaded hole; 9, second threaded hole; 10, third threaded hole; 11, main board; 12, air temperature and humidity monitoring sensor; 13, ultrasonic transducer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0048] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily limit to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0049] In the case of no conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0050] All data acquisition in this embodiment is based on compliance with laws, regulations and user consent, and is a legal application of data.

[0051] Embodiment 1

[0052] Please refer to the attached drawings of the specification Figures 1-3 The present invention provides a radar flowmeter with environmental compensation, including: an environmental compensation module and a monitoring module; the environmental compensation module is arranged on the upper housing (1) for precipitation and wind speed monitoring; the monitoring module is arranged on the lower housing (2) for water level and flow monitoring; the upper housing and the lower housing are fastened by bolts; the upper and lower housing structures are reasonably designed, facilitating installation and maintenance.

[0053] The environmental compensation module includes: a rain and snow monitoring sensor (6) and an air temperature and humidity monitoring sensor (12); the rain and snow monitoring sensor (6) is installed on the upper surface of the upper housing for precipitation monitoring; the air temperature and humidity monitoring sensor (12) is installed inside the upper housing for environmental humidity monitoring.

[0054] The monitoring module includes: a water level radio frequency radar and a flow velocity radio frequency radar; the water level radio frequency radar is fixed on the water level measurement cover plate (3) at the flat end of the lower housing; the flow velocity radio frequency radar is fixed on the flow velocity measurement cover plate (4) at the inclined end of the lower housing.

[0055] The included angle between the inclined end and the water surface is 45°.

[0056] The fact that the upper housing and the lower housing are fastened by bolts includes:

[0057] A plurality of first threaded holes (8) are provided on the upper surface of the upper housing, and a corresponding plurality of second threaded holes (9) are provided on the upper surface of the lower housing, and the hole positions of the first threaded holes and the second threaded holes correspond one by one;

[0058] Fix each first threaded hole and the corresponding second threaded hole one by one with bolts.

[0059] The upper shell is also provided with grid ventilation holes (7) around it for the internal and external air circulation; one side of the grid ventilation holes (7) is provided with an ultrasonic transducer (13), and the included angle between the central axis of the ultrasonic transducer and the plane of the grid ventilation holes ranges from 30° to 60°, preferably 45°. It is found that when the included angle is 45°, the signal coverage area is the largest and the diffraction loss is the lowest. The ultrasonic transducer is used to measure the environmental wind speed and direction.

[0060] In the existing radar flowmeter, the ultrasonic transducer is used to measure the environmental wind speed and direction, but its installation angle directly affects the measurement accuracy. If the included angle between the central axis of the ultrasonic transducer and the plane of the grid ventilation holes is set unreasonably (too large or too small), the following problems will occur:

[0061] 1. When the included angle is too large, >60°:

[0062] When the ultrasonic signal passes through the grid ventilation holes, due to the blocking or reflection of the grid structure, the signal attenuation is serious, resulting in an increase in the measurement error of the time difference of the downwind / upwind propagation.

[0063] In multi-path measurement, the wind speed component in the orthogonal direction cannot be accurately captured due to insufficient signal coverage.

[0064] 2. When the included angle is too small, <30°:

[0065] The coverage area of the ultrasonic signal is limited, and it is difficult to detect the airflow change completely, resulting in a deviation in the calculation of the wind speed component.

[0066] The diffraction interference of the edge of the grid ventilation holes on the signal is significant, reducing the signal-to-noise ratio.

[0067] The radar flowmeter also includes a main board (11), which is installed inside the upper shell and is electrically connected to the rain and snow monitoring sensor (6), the air temperature and humidity monitoring sensor (12), the ultrasonic transducer (13), the water level radio frequency radar and the flow velocity radio frequency radar respectively, for data processing and signal compensation.

[0068] The upper surface of the upper shell (1) is also provided with a third threaded hole (10) for installing an orientation adjustment joint to adjust the orientation of the device. The accuracy calibration during the installation process is ensured through the first threaded hole, the second threaded hole and the third threaded hole, further improving the overall performance.

[0069] The overall material is composed of aluminum-magnesium alloy and acetal resin. The environmental compensation part and the main body shell of the radar flowmeter are made of aluminum-magnesium alloy, and the speed measurement and distance measurement parts are made of ABS material. In one embodiment, the upper shell (1) and the lower shell (2) are made of aluminum-magnesium alloy, and the water level measurement cover plate (3) and the flow velocity measurement cover plate (4) are made of ABS cover plates.

[0070] A cylindrical hole (5) is provided on the upper surface of the lower shell (2), and a horizontal bubble level is provided in the cylindrical hole (5) for horizontal calibration during the installation process.

[0071] The water level measurement cover plate (3) is arranged at the flat end of the lower shell, and the water level measurement cover plate and the flat end of the lower shell are fixed with hexagon socket head cap screws. The radar frequency of the water level RF radar fixed on the water level measurement cover plate is 60 GHz, which real-time monitors the water level change in the channel and measures the flow velocity and water level of the channel in a non-contact manner.

[0072] The flow velocity measurement cover plate (4) is arranged at the side end of the lower shell, and the flow velocity measurement cover plate and the inclined end of the lower shell are fixed with hexagon socket head cap screws. The included angle between the inclined end and the water surface is 45°. The radar frequency of the flow velocity RF radar fixed on the flow velocity measurement cover plate is 24 GHz, which real-time monitors the water flow condition in the channel.

[0073] Embodiment 2

[0074] Please refer to the attached Figure 4 and 5 , a compensation method using the above-mentioned radar flowmeter with environmental compensation, the compensation method includes:

[0075] S101: Obtain the precipitation signal of the rain and snow monitoring sensor (6) and the humidity value of the air temperature and humidity monitoring sensor (12);

[0076] S102: Based on the precipitation signal and the humidity value, judge whether the current environment is precipitation or local dripping through the following logic: If the humidity value ≥ RH0 and the temperature dew point difference ≤ T0, it is determined as precipitation; if the humidity value < RH0 and the precipitation signal is detected, it is determined as local dripping; where, RH0 is the humidity threshold and T0 is the temperature dew point difference threshold;

[0077] In one embodiment, RH0 = 85%, T0 = 3°C. That is, if the humidity value ≥ 85% and the temperature dew point difference ≤ 3°C, it is determined as precipitation; if the humidity value < 85% and the precipitation signal is detected, it is determined as local dripping;

[0078] S103: When it is determined as precipitation, dynamically compensate the cross-sectional flow of the river channel to obtain the compensated cross-sectional flow; when it is determined as local dripping, there is no need to dynamically compensate the cross-sectional flow of the river channel.

[0079] S103: When it is determined to be precipitation, dynamic compensation is performed on the cross-sectional flow of the river channel. The calculation formula for the dynamic compensation of the cross-sectional flow is as follows:

[0080] Q = k * v * A

[0081] In the formula, Q: the cross-sectional flow after compensation; v: the surface velocity; A: the cross-sectional area of the water flow; k: the correction coefficient.

[0082] When it is determined to be local dripping, no dynamic compensation is required for the cross-sectional flow of the river channel, and the cross-sectional flow is equal to the product of the surface velocity and the cross-sectional area of the water flow.

[0083] S1031: The calculation formula for the correction coefficient k is as follows:

[0084]

[0085] Wherein, RH is the air humidity, P is the rainfall, V 风 is the wind speed, α is the air humidity coefficient obtained by simulating the on-site air humidity in the laboratory, β is the rainfall coefficient obtained by simulating the on-site rainfall in the laboratory, and γ is the wind speed coefficient obtained by simulating the on-site wind speed in the laboratory.

[0086] The inventor found based on laboratory simulations that:

[0087] The influence of humidity on signal attenuation is approximately exponential, that is, the attenuation increases sharply when the humidity approaches saturation.

[0088] The influence of rainfall on signal attenuation approximately follows a non-linear law and tends to saturate as the rainfall increases.

[0089] The influence of wind speed on signal attenuation decreases with the increase of speed showing a marginal effect.

[0090] The specific values of the coefficients α, β, and γ are obtained by fitting through laboratory simulation experiments (such as wind tunnel and flume tests) combined with actual parameters such as cross-sectional shape and water flow conditions.

[0091] In S1031, in the calculation of the correction coefficient, the calculation methods and principles of humidity, rainfall, and wind speed in the correction coefficient include:

[0092] (I) Humidity

[0093] The air temperature and humidity are obtained using the SHT3X series sensors of Sensirion (Sensirion, Switzerland), which is a fully calibrated and linearized digital temperature and humidity sensor with high reliability and high stability.

[0094] SHT3X temperature and humidity conversion method:

[0095] Conversion of signal output: Measurement data is always transmitted in the form of 16-bit values (unsigned integers). These values have been linearized and compensated for the effects of temperature and supply voltage. The conversion of these raw values to the physical scale can be achieved using the following formula. Relative humidity conversion formula (result in %RH):

[0096]

[0097] S RH and S T Output of the raw data indicating temperature and humidity. The calculated result is decimal data.

[0098] (2) Rainfall

[0099] Based on the change of the voltage waveform, the precipitation situation can be obtained, thereby realizing the measurement of the weight of a single raindrop and further calculating the rainfall.

[0100] The specific principle is as follows:

[0101] 1. Basic relationship between temperature, humidity and rainfall

[0102] The formation of rainfall requires water vapor in the air to reach saturation (relative humidity ≈ 100%) and condense into water droplets. The air temperature and humidity monitoring sensor (12) can indirectly judge the degree of air approaching saturation by measuring the temperature (T) and relative humidity (RH), and then infer the possibility of rainfall.

[0103] 2. Key parameters and formulas

[0104] (1) Relative humidity (RH)

[0105] Definition: The percentage of the current vapor pressure to the saturated vapor pressure at the same temperature.

[0106] Formula:

[0107]

[0108] e: Actual vapor pressure (unit: hPa)

[0109] e s : Saturated vapor pressure (temperature-related)

[0110] (2) Saturated vapor pressure (e s )

[0111] Magnus formula (commonly used approximation):

[0112]

[0113] (3) Dew point temperature (T d )

[0114] Definition: The temperature when air is cooled to saturation (RH = 100%).

[0115] Approximate calculation (given T and RH):

[0116]

[0117] (4) Temperature dew point difference (T - T d )

[0118] Physical meaning: The smaller the difference, the closer the air is to saturation.

[0119] Empirical relationship: T - T d < 2°C: High humidity, possible rainfall.

[0120] T - T d < 0°C: Supersaturated (commonly seen in fog or clouds).

[0121] 3. Logic chain for rainfall prediction

[0122] (1) High relative humidity (RH > 80%) → High water vapor content in the air.

[0123] (2) Temperature dew point difference (T - T d ) approaching 0 → Air approaching saturation.

[0124] (3) Cooling or lifting mechanism (such as cold front, orographic lifting) → Trigger condensation and form precipitation.

[0125] 4. Example model (empirical formula)

[0126] Rainfall probability P rain Can be simplified to:

[0127]

[0128] (III) Wind speed

[0129] Calculation methods for wind speed V 风 include:

[0130] S104: Calculation of wind speed in the east - west direction,

[0131] where, is the wind speed component in the east - west direction, t1 is the downwind propagation time in the east - west direction, t2 is the upwind propagation time in the east - west direction, L x is the distance between ultrasonic transducers in the east - west direction, v x is the wind speed in the east - west direction measured by the ultrasonic transducer, c is the speed of sound;

[0132] S105: Calculation of wind speed in the north - south direction,

[0133] Among them, is the wind speed component in the east-west direction, t3 is the downwind propagation time in the east-west direction, and t4 is the upwind propagation time in the east-west direction. L y is the distance between ultrasonic transducers in the east-west direction, v y is the wind speed in the north-south direction measured by the ultrasonic transducer, and c is the speed of sound.

[0134] S106: Synthesize the total wind speed and wind direction angle. V 风 is the total wind speed. The wind direction angle takes the true north as 0°, and rotates clockwise. δ is the angle correction value.

[0135] The propagation of sound waves is affected by the wind speed: when ultrasonic waves propagate in the air, the propagation speed increases in the downwind direction and decreases in the upwind direction. By measuring the time difference of propagation in two opposite directions, the wind speed component can be calculated.

[0136] Multipath measurement: The instrument is usually equipped with 2 pairs or 3 pairs of ultrasonic transducers (arranged orthogonally in pairs) to measure the wind speed components in different directions (such as east-west, north-south), and then obtain the total wind speed and wind direction through vector synthesis.

[0137] Temperature compensation: The speed of sound is affected by temperature (the formula is c = 331.5 + 0.6T, where T is the temperature in °C), so the temperature needs to be measured in real time to correct the speed of sound value.

[0138] In a specific embodiment, the calculation formula is as follows:

[0139] 1. Uniaxial wind speed calculation (taking the east-west direction as an example)

[0140] Assume that the distance between a pair of transducers is L, the downwind (east → west) propagation time is t1, the upwind (west → east) propagation time is t2, the wind speed component is v x , and the speed of sound is c:

[0141] Downwind propagation time:

[0142] Upwind propagation time:

[0143] Solve the simultaneous equations to obtain the wind speed component:

[0144] 2. Synthesize the wind speed and wind direction angle

[0145] Assume that the measured wind speed components in the orthogonal directions are and Then:

[0146] Total wind speed:

[0147] Wind direction angle (with true north as 0°, rotating clockwise):

[0148] δ is the angle correction value (the quadrant needs to be adjusted according to the actual coordinate system).

[0149] Time measurement accuracy: A high-precision timing circuit is required (usually reaching the nanosecond level).

[0150] The ultrasonic transducer measures the time difference of ultrasonic wave propagation, combines temperature compensation and multi-axis vector synthesis to achieve high-precision and fast-response wind speed and direction measurement. Its core formula is based on the superposition relationship between the sound speed and the wind speed, and is applicable to fields such as meteorological monitoring, wind power, and environmental monitoring.

[0151] S1032: The surface flow velocity is calculated according to the Doppler effect formula. The corresponding relationship between frequency and surface flow velocity in the Doppler effect is:

[0152]

[0153] where f d is the current frequency value, v is the surface flow velocity, and α is the installation angle between the radar flowmeter and the water surface.

[0154] The working principle of the Doppler radar can be described as follows: When the radar emits a pulsed wave with a fixed frequency to scan the water surface, if it encounters a moving target, the frequency of the echo will be different from the frequency of the transmitted wave, which is called the Doppler frequency. According to the magnitude of the Doppler frequency, the radial relative motion speed of the target with respect to the radar can be measured.

[0155] Relative motion speed; According to the time difference between the transmitted pulse and the received one, the distance to the target can be measured. At the same time, the Doppler frequency spectrum line of the target is detected by the frequency filtering method, and the spectrum lines of interference clutter are filtered out, so that the radar can distinguish the target signal from strong clutter. Therefore, the Doppler radar has stronger anti-clutter interference ability than ordinary radars and can detect moving targets hidden in the background.

[0156] Doppler theory basis: A wave is composed of frequency and amplitude, and radio waves move with the object. When the radio wave travels and encounters an object, the radio wave will be reflected, and the frequency and amplitude of the reflected wave will change according to the moving state of the object it encounters. If the object encountered by the radio wave is stationary, then the frequency of the reflected radio wave will not change. However, if the object is moving towards the direction of the radio wave emission, the reflected radio wave will be compressed at this time, so the frequency of this radio wave will increase; conversely, if the object is moving away from the radio wave direction, the frequency of the reflected radio wave will decrease.

[0157] S1033: Calculation method for cross-sectional area A:

[0158] For natural rivers, establish a water level - area relationship curve (H - A curve) through historical survey GIS data, and it can be obtained by looking up the table according to the real-time water depth;

[0159] For regular channels (such as rectangular and trapezoidal), the calculation formula for the cross-sectional area is as follows:

[0160] A = b·h + m·h 2

[0161] Where, A is the cross-sectional area, b is the bottom width of the channel, m is the side slope coefficient, and h is the water depth.

[0162] The specific water depth h can be obtained based on the time difference between the radar wave reaching the bottom and the water surface. The specific calculation principle is as follows:

[0163] Calculate the water depth based on the FMCW principle. FMCW is the abbreviation of the first letters of the English words Frequency Modulated Continuous Wave. The FMCW microwave level gauge uses a linearly modulated high-frequency signal, generally using 10 GHz or 24 GHz microwave signals. It is an indirect measurement method based on complex mathematical formulas, and the level distance is calculated from the spectrum. The antenna emits a linearly modulated continuous high-frequency microwave signal and scans it, while receiving the return signal. There is a certain proportional relationship between the frequency difference between the transmitted microwave signal and the returned microwave signal and the distance to the medium surface.

[0164] Perform water level calculation based on the above principle:

[0165] Transmission frequency f t And the reflected frequency f r The difference is the frequency difference f b

[0166] f b = f t - f r (1)

[0167]

[0168] Where, D is the straight-line distance from the radar to the target; t d Is the time taken for the signal emitted by the radar to reach the target; c is the speed of light (constant);

[0169] The frequency-modulated triangular wave generated by the frequency synthesizer and VCO has formula (3) according to the similar triangles

[0170]

[0171] Substitute (2) and simplify to get (4).

[0172]

[0173] Among them, c is the speed of light (constant), and t s is half of the period of the frequency-modulated wave generated by the frequency generator, and f DEV is the frequency sweep bandwidth of the frequency-modulated wave. From this, it can be concluded that the detection range of the FMCW radar is a function of f b when other values are determined.

[0174] That is, the distance equation of the radar is:[[]]

[0175] Among them, D is the straight-line distance from the radar signal to the target, C is the speed of light, and f b is the difference between the transmitted frequency and the reflected frequency, S is the slope, and S = f DEV / t s ;

[0176] When t s is the distance from the radar flowmeter to the bottom of the open channel, the distance H0 from the radar flowmeter to the bottom of the open channel can be calculated using the distance equation of the radar;

[0177] When t s is the distance from the radar flowmeter to the water surface, the distance H1 from the radar flowmeter to the water surface can be calculated using the distance equation of the radar;

[0178] The equation for calculating the water depth h: h = H0 - H1, where h is the water level depth in the open channel, H0 is the distance from the radar flowmeter to the bottom of the open channel, and H1 is the distance from the radar flowmeter to the water surface.

[0179] The radar flowmeter with environmental compensation and its compensation method disclosed in the present invention can be applied in the following scenarios:

[0180] (1) Water resource management: Real-time monitoring of the flow rate and water level of natural water bodies such as rivers and lakes, providing a scientific basis for the reasonable allocation and scheduling of water resources. Managers can thereby timely understand the water resource dynamics, optimize the irrigation plan, reduce waste, and ensure the effective supply of agricultural, industrial, and residential water. Used for water volume monitoring and management of reservoirs, real-time monitoring of the inflow and outflow of reservoirs, providing accurate data support for the water volume scheduling and management of reservoirs, helping to prevent flood disasters, and ensuring the water supply capacity of reservoirs in the dry season.

[0181] (2) Flood control and disaster reduction: It can be unaffected by floating objects and sediment on the water surface, quickly respond to water level changes, provide timely and accurate data support for flood control decision-making, and effectively reduce the losses caused by flood disasters. For example, in river channel monitoring, it can monitor the flow rate changes of the river channel in real time, provide reliable data for flood forecasting and scheduling of the river channel, and can also monitor the water level changes of the river channel, timely detect problems such as river channel siltation and blockage, and provide guidance for river channel maintenance and management.

[0182] (3) Agricultural irrigation: It can monitor the inflow and outflow of water in the irrigation area in real time, provide accurate data support for irrigation scheduling and management of the irrigation area, precisely control the irrigation water volume, improve the utilization efficiency of water resources, and contribute to the realization of the development goal of precision agriculture.

[0183] (4) Water conservancy projects: In the flow monitoring of dams, sluices, etc., it helps users understand the operation status of the projects and ensure the safe and stable operation of the projects.

[0184] (5) Urban water service: In the urban water supply system, it can monitor the flow rate of the water supply pipeline in real time to ensure the safe operation of the water supply pipeline, and can also detect the operation faults of the water pump in time by monitoring the inlet and outlet flow rates of the water pump, providing guarantee for the stable operation of the water supply system.

[0185] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. A radar flowmeter with environmental compensation, characterized in that Including: An environmental compensation module and a monitoring module; the environmental compensation module is arranged on the upper shell (1) for precipitation and wind speed monitoring; The monitoring module is arranged on the lower shell (2) for water level and flow monitoring; The upper shell and the lower shell are fastened by bolts; The environmental compensation module includes: a rain and snow monitoring sensor (6) and an air temperature and humidity monitoring sensor (12); the rain and snow monitoring sensor (6) is installed on the upper surface of the upper shell for precipitation monitoring; the air temperature and humidity monitoring sensor (12) is installed inside the upper shell for environmental humidity monitoring; The monitoring module includes: a water level radio frequency radar and a flow velocity radio frequency radar; the water level radio frequency radar is fixed on the water level measurement cover plate (3) at the flat end of the lower shell; the flow velocity radio frequency radar is fixed on the flow velocity measurement cover plate (4) at the inclined end of the lower shell.

2. The radar flowmeter with environmental compensation according to claim 1, wherein The upper shell and the lower shell being fastened by bolts includes: A plurality of first threaded holes (8) are provided on the upper surface of the upper shell, and a corresponding plurality of second threaded holes (9) are provided on the upper surface of the lower shell, and the hole positions of the first threaded holes and the second threaded holes correspond one by one; Each first threaded hole and the corresponding second threaded hole are fixed one by one through bolts.

3. The radar flowmeter with environmental compensation according to claim 1, wherein Grid ventilation holes (7) are further provided around the upper shell for internal and external air circulation; One side of the grid ventilation hole (7) is provided with an ultrasonic transducer (13), and the included angle between the central axis of the ultrasonic transducer and the plane of the grid ventilation hole ranges from 30° to 60°, and the ultrasonic transducer is used for measuring the environmental wind speed and direction.

4. The radar flowmeter with environmental compensation according to claim 1, characterized in that, It further includes a control module, and the control module includes a main board (11), and the main board (11) is installed inside the upper shell and is electrically connected to the rain and snow monitoring sensor (6), the air temperature and humidity monitoring sensor (12), the ultrasonic transducer (13), the water level radio frequency radar and the flow velocity radio frequency radar respectively for data processing and signal compensation.

5. The radar flowmeter with environmental compensation according to claim 1, characterized in that, A third threaded hole (10) is further provided on the upper surface of the upper shell (1) for installing an orientation adjusting joint to adjust the orientation of the device.

6. The compensation method of the radar flowmeter with environmental compensation according to any one of claims 1-5, characterized in that, The compensation method includes: S101: Obtain the precipitation signal of the rain and snow monitoring sensor (6) and the humidity value of the air temperature and humidity monitoring sensor (12); S102: Based on the precipitation signal and the humidity value, judge whether the current environment is precipitation or local dripping through the following logic: If the humidity value ≥ RH0 and the temperature dew point difference ≤ T0, it is determined as precipitation; if the humidity value < RH0 and a precipitation signal is detected, it is determined as local dripping; where RH0 is the humidity threshold and T0 is the temperature dew point difference threshold; S103: When it is determined as precipitation, dynamically compensate the cross-sectional flow of the river channel to obtain the compensated cross-sectional flow; when it is determined as local dripping, there is no need to dynamically compensate the cross-sectional flow of the river channel.

7. The compensation method according to claim 6, wherein In the said S103: When it is determined as precipitation, dynamically compensate the cross-sectional flow of the river channel, and the dynamic compensation calculation formula for the cross-sectional flow is: Q = k * v * A In the formula, Q: the compensated cross-sectional flow; v: the surface flow velocity; A: the cross-sectional area of the water flow; k: the correction coefficient.

8. The compensation method according to any one of claims 7, characterized in that The calculation formula for the correction coefficient k is: Among them, RH is the air humidity, P is the rainfall, V 风 is the wind speed, α is the air humidity coefficient obtained by simulating the on-site air humidity in the laboratory, β is the rainfall coefficient obtained by simulating the on-site rainfall in the laboratory, and γ is the wind speed coefficient obtained by simulating the on-site wind speed in the laboratory.

9. The compensation method according to claim 7, wherein The surface flow velocity is calculated according to the Doppler effect formula. The corresponding relationship between the frequency and the surface flow velocity in the Doppler effect is as follows: where f d is the current frequency value, v is the surface flow velocity, and α is the installation angle between the radar flowmeter and the water surface.

10. The compensation method according to claim 8, characterized in that The wind speed V 风 is calculated as follows: S104: Calculation of east-west wind speed, Among them, v x is the wind speed component in the east-west direction, t1 is the downwind propagation time in the east-west direction, t2 is the upwind propagation time in the east-west direction, L x is the distance between the ultrasonic transducers in the east-west direction, v x is the wind speed in the east-west direction measured by the ultrasonic transducer, and c is the speed of sound; S105: Calculation of wind speed in the north-south direction, Among them, v y is the wind speed component in the east-west direction, t3 is the downwind propagation time in the east-west direction, and t4 is the upwind propagation time in the east-west direction. L y is the distance between ultrasonic transducers in the east-west direction, v y is the wind speed in the north-south direction measured by the ultrasonic transducer, and c is the speed of sound. S106: Synthesize the total wind speed and the wind direction angle. V 风 is the total wind speed. The wind direction angle takes the due north as 0° and rotates clockwise. δ is the angle correction value.

Images