A three-element ultrasonic wind measuring device and measurement method with mutual resonant force.

Abstract

This invention relates to a three-element ultrasonic anemometer and its measurement method, belonging to the field of wind speed and direction measurement technology. It includes three ultrasonic sensors, a transmitting module, a transmitting gating switch module, a receiving module, a receiving gating switch module, an AD conversion module, a central processing unit module, a display module, and a communication module. The three transceiver ultrasonic sensors are arranged in an equilateral triangle configuration. By having the three ultrasonic sensors alternately transmit and receive ultrasonic signals, and using a quadratic correlation algorithm to calculate the ultrasonic wave propagation time between any two sensors, the actual wind speed and direction can be calculated. The advantages are that it eliminates the obstruction effect caused by the ultrasonic sensors blocking the wind, improving the measurement accuracy of wind speed and direction, and also eliminating the influence of environmental factors such as temperature and humidity on the measurement results.

Description

Technical Field

[0001] This invention belongs to the field of wind speed and direction measurement technology, specifically relating to a mutually resonant three-element ultrasonic wind measuring device and measurement method. Background Technology

[0002] Wind speed and direction measurement has become an important research topic in meteorology, military, industry, and aerospace and maritime fields. Traditional mechanical anemometers, due to the aging and wear of rotating parts leading to inaccurate measurements of wind speed and direction, and the reliance on starting wind speed and other factors, have been gradually replaced by modern wind measurement technologies such as ultrasonic anemometers. Ultrasonic anemometers have advantages such as simple structure, no mechanical wear, low starting wind speed, wide measurement range, and high accuracy, and have become the mainstream product in the current field of wind speed and direction measurement.

[0003] There are many methods for measuring wind speed and direction using ultrasonic measuring instruments, such as the time-of-flight method, frequency difference method, Doppler method, and karman vortex method. Among these, the frequency difference method, Doppler method, and karman vortex method are less commonly used in conventional wind speed and direction measurements due to limitations in their measurement principles and various problems encountered during the measurement process. In contrast, the time-of-flight method can calculate wind speed and direction values ​​simply by measuring the ultrasonic wave transmission time. Its greatest advantage is its simple measurement principle and high accuracy, making it the most widely used method in current research and application.

[0004] The accuracy of wind speed and direction measurements using the time-of-flight method depends entirely on the accuracy of the ultrasonic transmission time measurement. There are two main types of methods for measuring signal transmission time: First, measurement is performed using custom-designed application-specific integrated circuits (ASICs) based on CMOS (Complementary Metal-Oxide Semiconductor) technology or hardware timing circuits built on FPGAs (Field Programmable Gate Arrays). This type of technology is relatively mature and has high resolution. However, a high-resolution timing method does not guarantee the same high-resolution measurement accuracy, because the ultrasonic signals being measured often contain strong noise or interference. Without effective suppression of this noise or interference, this type of method cannot obtain the true start and end points of the transmitted and received signals, ultimately leading to large errors in wind speed and direction measurement. Second, propagation time is estimated using a single-correlation detection algorithm from modern detection and signal processing fields. This method does not require peak detection or threshold comparison circuits; it obtains the time delay value simply by measuring the transmitted and received signals and performing correlation calculations. Compared to hardware timing circuit methods, it is simpler to implement. However, the single-correlation detection method still has limited noise suppression capabilities and generally cannot meet the measurement accuracy requirements when the signal-to-noise ratio is low. In addition, most current ultrasonic anemometers have an orthogonal beam structure consisting of four ultrasonic sensors. Orthogonal beam ultrasonic anemometer systems suffer from the problem of obstruction effect caused by the ultrasonic sensors blocking the wind speed. Summary of the Invention

[0005] This invention provides a three-element ultrasonic wind measuring device and method with mutual beams to solve the problem of the blocking effect caused by the ultrasonic sensor blocking in the existing orthogonal beam ultrasonic wind measuring system.

[0006] The technical solution adopted in this invention is a three-element ultrasonic wind measuring device with mutual emission, comprising an ultrasonic sensor 1, an ultrasonic sensor 2, an ultrasonic sensor 3, a transmitting module, a transmitting gating switch module, a receiving module, a receiving gating switch module, an AD conversion module, a central processing unit module, a display module, and a communication module. The three ultrasonic sensors are arranged in an equilateral triangle configuration. All three ultrasonic sensors are connected to the output terminal of the transmitting gating switch module and the input terminal of the receiving gating switch module. The input terminal of the transmitting gating switch module is connected to the output terminal of the transmitting module, and the input terminal of the transmitting module is connected to the central processing unit module. The receiving gating switch module is connected to the receiving module, and the output terminal of the receiving module is connected to the input terminal of the AD conversion module. The output terminal of the AD conversion module is connected to the central processing unit module. The central processing unit module is connected to the display module and the communication module, used to display and transmit the final measured wind speed and direction values.

[0007] The ultrasonic sensor 1, ultrasonic sensor 2, and ultrasonic sensor 3 described in this invention are transceiver integrated ultrasonic sensors.

[0008] A measurement method using a mutually resonant three-element ultrasonic anemometer includes the following steps:

[0009] Step 1: After powering on the device, initialize each module;

[0010] Step 2: After initialization, the central processing unit module controls the transmit gating switch module to select ultrasonic sensor one as the transmitting probe, and at the same time, the central processing unit module controls the receive gating switch module to select ultrasonic sensor two and ultrasonic sensor three as receiving probes.

[0011] Step 3: After the receiving module sends the received signal to the AD conversion module, it transmits it to the central processing module for storage. Then, the propagation time between the transmitted and received signals is calculated using the quadratic correlation method. The estimated propagation times of the ultrasonic waves from ultrasonic sensor one to ultrasonic sensor two and ultrasonic sensor three are given: The estimated propagation time of the ultrasonic waves from ultrasonic sensor one to ultrasonic sensor two is... The estimated propagation time of the ultrasonic wave from ultrasonic sensor one to ultrasonic sensor three is:

[0012] Step 4: The central processing unit module controls the transmit gating switch module to select ultrasonic sensor 2 as the transmitting probe, and at the same time, the central processing unit module controls the receive gating switch module to select ultrasonic sensor 1 and ultrasonic sensor 3 as the receiving probes.

[0013] Step 5: The receiving module sends the received signal to the AD conversion module, then to the central processing module for storage. The propagation time between the transmitted and received signals is then calculated using the quadratic correlation method. Estimates are given for the propagation times of the ultrasonic waves from ultrasonic sensor 2 to ultrasonic sensor 1 and ultrasonic sensor 3: The estimated propagation time of the ultrasonic wave from ultrasonic sensor 2 to ultrasonic sensor 1 is... The estimated propagation time of the ultrasonic wave from ultrasonic sensor two to ultrasonic sensor three is:

[0014] Step Six: The central processing unit module controls the transmit gating switch module to select ultrasonic sensor three as the transmitting probe, and at the same time, the central processing unit module controls the receive gating switch module to select ultrasonic sensor one and ultrasonic sensor two as receiving probes.

[0015] Step 7: The receiving module sends the received signal to the AD conversion module, then to the central processing module for storage. The propagation time between the transmitted and received signals is then calculated using the quadratic correlation method. Estimates are given for the propagation times of the ultrasonic waves from ultrasonic sensor 3 to ultrasonic sensors 1 and 2: The estimated propagation time of the ultrasonic wave from sensor 3 to sensor 1 is... The estimated propagation time of the ultrasonic wave from sensor three to sensor two is:

[0016] Step 8: Obtain the ultrasonic propagation time between each ultrasonic sensor by taking turns transmitting and receiving once, and then calculate the wind speed component in the direction of each ultrasonic sensor based on the measured ultrasonic propagation time.

[0017] From step three, we can know that the estimated propagation time of the ultrasonic wave from ultrasonic sensor one to ultrasonic sensor two is... From step five, we know that the propagation time of the ultrasonic wave from ultrasonic sensor two to ultrasonic sensor one is... Then the wind speed components in the directions from ultrasonic sensor one to ultrasonic sensor two can be obtained as follows:

[0018]

[0019] In the formula: L represents the distance between ultrasonic sensors;

[0020] The estimated propagation time of the ultrasonic wave from ultrasonic sensor one to ultrasonic sensor three in step three is... From step seven, we know that the propagation time of the ultrasonic wave from ultrasonic sensor three to ultrasonic sensor one is... Then the wind speed components in the three directions of the ultrasonic sensor can be obtained as follows:

[0021]

[0022] From step five, we can know that the estimated propagation time of the ultrasonic wave from ultrasonic sensor two to ultrasonic sensor three is... From step seven, we know that the propagation time of the ultrasonic wave from ultrasonic sensor three to ultrasonic sensor two is... Then the wind speed components in the direction from ultrasonic sensor three to ultrasonic sensor two can be obtained as follows:

[0023]

[0024] Step 9: Calculate the actual wind speed and direction based on the wind speed components along the directions of each ultrasonic sensor. The wind speed components along the directions from ultrasonic sensor one to ultrasonic sensor two are V. 12The wind speed components in the three directions of the ultrasonic sensor are V. 13 The relationship between the wind speed component and the actual wind speed and direction is as follows:

[0025] V 12 =Vcos(θ-π / 6)

[0026] V 13 =Vcos(θ+π / 6)

[0027] Solving the system of equations simultaneously yields a set of actual wind speeds V1 and wind directions θ1, which are as follows:

[0028]

[0029]

[0030] Wind speed component V from ultrasonic sensor one to ultrasonic sensor two 12 The wind speed components V in the three directions from the ultrasonic sensor to the ultrasonic sensor 32 The relationship between the wind speed component and the actual wind speed and direction is as follows:

[0031] V 12 =Vcos(θ-π / 6)

[0032] V 32 =Vsinθ

[0033] Solving the system of equations simultaneously yields another set of actual wind speeds V2 and wind directions θ2, which are:

[0034]

[0035]

[0036] Wind speed components V in the three directions of the ultrasonic sensor 13 The wind speed components V in the two to three directions of the ultrasonic sensor. 32 The relationship between the wind speed component and the actual wind speed and direction is as follows:

[0037] V 13 =Vcos(θ+π / 6)

[0038] V 32 =Vsinθ

[0039] Solving the system of equations simultaneously yields the actual wind speed V3 and wind direction θ3 for the third set of values:

[0040]

[0041]

[0042] Step 10: Averaging the three sets of wind speed and direction values ​​yields the final wind speed and direction. This not only eliminates the obstruction effect caused by a single ultrasonic sensor blocking the signal, but also further improves noise suppression and the accuracy of wind speed and direction measurement. The final wind speed and direction are as follows:

[0043]

[0044]

[0045] Step 11: Display the wind speed and direction values ​​from Step 10 through the display module and output them through the communication module. Then return to Step 2. Repeat this process to obtain the wind speed and direction values ​​at different times.

[0046] The present invention discloses a method for measuring wind using a three-element ultrasonic transducer, characterized in that: in step two, the transmitted signal of the ultrasonic sensor one is:

[0047] x1(t) = s(t) + n(t)

[0048] In the formula: The signal represents the driving signal, A represents the amplitude of the ultrasonic wave transmitted signal, k represents the Gaussian coefficient, and ω = 2πf represents the ultrasonic wave angular frequency. Let n(t) represent the initial phase, and n(t) represent the additional noise in the transmitted signal.

[0049] The received signals of ultrasonic sensor two and ultrasonic sensor three are:

[0050] y 1i (t)=s(t-τ 1i )+n 1i (t)

[0051] In the formula: τ represents the delayed signal, B represents the amplitude of the received ultrasonic signal, and τ represents the amplitude of the received ultrasonic signal. 1i This represents the propagation time of an ultrasonic wave from ultrasonic sensor 1 to the i-th ultrasonic sensor, where n is the propagation time. 1i (t) represents the noise added to the received signal.

[0052] In step three of this invention, the specific method for determining the ultrasonic wave propagation time using the quadratic correlation method is as follows: ultrasonic sensor one transmits, and ultrasonic sensor two and ultrasonic sensor three receive:

[0053] Performing an autocorrelation operation on the transmitted signal x1(t), we obtain:

[0054] R xx (τ)=E[x1(t)x1(t-τ)]=R ss (τ)+R sn(τ)+R ns (τ)+R nn (τ)

[0055] In the formula: R xx (τ) represents the autocorrelation function of the transmitted signal x1(t), E(·) represents the expectation, and R ss (τ) represents the autocorrelation function of the driving signal s(t), R sn (τ) represents the correlation function between the driving signal s(t) and the additional noise n(t) of the transmitted signal, R ns (τ) represents the correlation function between the additional noise n(t) of the transmitted signal and the driving signal s(t), R nn (τ) represents the autocorrelation function of the additional noise n(t) of the transmitted signal;

[0056] Since the driving signal s(t) is uncorrelated with the additional noise n(t) of the transmitted signal, the correlation function R sn (τ)=R ns (τ)=0, therefore:

[0057] R xx (τ)=R ss (τ)+R nn (τ)

[0058] Furthermore, since the emitted noise is white noise, its power spectral density is S. n (ω)=N0, where N0 is a constant. Substitute the transmitted signal x1(t) into the autocorrelation function R. xx In (τ), we get:

[0059]

[0060] In the above formula If the long-time integral is zero, then:

[0061]

[0062] In the formula: δ(τ) represents the Dirac function;

[0063] For the transmitted signal x1(t) and the received signal y 1i Performing cross-correlation on (t) yields:

[0064]

[0065] In the formula: Represents the transmitted signal x1(t) and the received signal y 1i The cross-correlation function between (t) and R0 ss (τ-τ 1i ) represents the driving signal s(t) and the delayed signal s(t-τ).1i Correlation functions between ) and R sn (τ-τ 1i ) represents the delayed signal s(t-τ) 1i The correlation function between the transmitted signal and the additional noise n(t) is given. This represents the noise n added to the driving signal s(t) and the received signal. 1i The correlation function between (t) The noise n(t) of the transmitted signal and the noise n of the received signal are represented by the following values. 1i The correlation function between (t);

[0066] Due to the additional noise n in the driving signal s(t) and the received signal 1i (t) is uncorrelated, and the delayed signal s(t-τ) 1i The transmitted signal's added noise n(t) is uncorrelated with the received signal's added noise n(t). 1i If (t) is uncorrelated, then the correlation function have:

[0067]

[0068] Receive signal y 1i (t)=s(t-τ 1i )+n 1i (t) Substitute into the cross-correlation function In the middle, we get:

[0069]

[0070] In the formula:

[0071] Observe the autocorrelation function R xx (τ) and cross-correlation function Both are functions of time delay τ. Treating them as new functions, we perform correlation operations on them again to obtain the quadratic correlation function:

[0072]

[0073] In the formula: R SS (κ-τ 1i ) represents and The correlation function between them, namely:

[0074]

[0075] R SN (κ) is The correlation function between N0δ(τ) and N0δ(τ) is:

[0076]

[0077] Then the quadratic correlation function R RR (κ) can be represented as:

[0078]

[0079] Because the quadratic correlation function is in κ=τ 1i The maximum value is taken at time, that is:

[0080] R RR (κ)≤R SS (0)+R SN (τ 1i )

[0081] Therefore, by finding its maximum value, the estimated propagation time of the ultrasonic signal through ultrasonic sensor one to ultrasonic sensor two and ultrasonic sensor three can be obtained:

[0082]

[0083] In step four of this invention, the transmitted signal of the ultrasonic sensor two is:

[0084] x²(t) = s(t) + n(t)

[0085] In the formula: The signal represents the driving signal, A represents the amplitude of the ultrasonic wave transmitted signal, k represents the Gaussian coefficient, and ω = 2πf represents the ultrasonic wave angular frequency. Let n(t) represent the initial phase, and n(t) represent the additional noise in the transmitted signal.

[0086] The received signals of ultrasonic sensor one and ultrasonic sensor three are as follows:

[0087] y 2i (t)=s(t-τ 2i )+n 2i (t)

[0088] In the formula: τ represents the delayed signal, B represents the amplitude of the received ultrasonic signal, and τ represents the amplitude of the received ultrasonic signal. 2i n represents the propagation time of an ultrasonic wave from ultrasonic sensor 2 to the i-th ultrasonic sensor. 2i (t) represents the noise added to the received signal.

[0089] In step six of this invention, the transmitted signal of ultrasonic sensor three is:

[0090] x3(t) = s(t) + n(t)

[0091] In the formula: The signal represents the driving signal, A represents the amplitude of the ultrasonic wave transmitted signal, k represents the Gaussian coefficient, and ω = 2πf represents the ultrasonic wave angular frequency. Let n(t) represent the initial phase, and n(t) represent the additional noise in the transmitted signal.

[0092] The received signals of ultrasonic sensor one and ultrasonic sensor two are:

[0093] y 3i (t)=s(t-τ 3i )+n 3i (t)

[0094] In the formula: τ represents the delayed signal, B represents the amplitude of the received ultrasonic signal, and τ represents the amplitude of the received ultrasonic signal. 3i n represents the propagation time of an ultrasonic wave from the third ultrasonic sensor to the i-th ultrasonic sensor. 3i (t) represents the noise added to the received signal.

[0095] Advantages and positive effects of the present invention:

[0096] (1) The shading effect has been eliminated.

[0097] Traditional ultrasonic anemometers suffer from the problem of obstruction effect. When the wind being measured comes from behind the ultrasonic probe, the probe's obstruction leads to significant deviations in wind speed and direction measurements. The measurement device and method provided in this invention eliminate the obstruction effect to a certain extent. The measurement device uses three ultrasonic sensors arranged in an equilateral triangle configuration. Three sets of wind speed and direction values ​​are obtained through a measurement mode where the three sensors alternately transmit and receive. These values ​​are then averaged to obtain the final wind speed and direction, thus largely solving the problem of large measurement deviations caused by a single ultrasonic sensor obstructing the wind speed measurement. Furthermore, the mutually reflective three-element array structure provided in this invention avoids the need for real-time measurement of ambient temperature and humidity to correct the sound velocity of the ultrasonic waves.

[0098] (2) High measurement accuracy.

[0099] Compared with traditional ultrasonic anemometers, the measuring device and method provided by this invention significantly improve measurement accuracy. Firstly, the measuring device uses a quadratic correlation method to measure the ultrasonic wave propagation time, which has stronger noise suppression capabilities and higher measurement accuracy compared to other time delay measurement methods. Secondly, the alternating three-element wind measurement structure provided by this invention obtains three sets of wind speed and direction values ​​through three alternating transmission and reception measurements, and then averages these values ​​to obtain the final wind speed and direction, further improving the measurement accuracy. Attached Figure Description

[0100] Figure 1This is a system schematic diagram of the present invention;

[0101] Figure 2 This is a schematic diagram of the ultrasonic sensor arrangement of the present invention;

[0102] Figure 3 This is a measurement schematic diagram of the present invention;

[0103] Figure 4 This is the wind speed and direction vector decomposition diagram of the present invention;

[0104] Figure 5 This is a flowchart of the present invention;

[0105] Figure 6 This is a graph showing the results of multiple wind speed measurements under fixed wind speed conditions;

[0106] Figure 7 This is a graph showing the results of multiple wind direction measurements under fixed wind direction conditions;

[0107] Figure 8 These are graphs showing the measurement results at different wind speeds;

[0108] Figure 9 This is a graph showing the measurement results under different wind directions. Detailed Implementation

[0109] like Figure 1 , Figure 2 As shown, a three-element ultrasonic wind measuring device includes an ultrasonic sensor 1, an ultrasonic sensor 2, an ultrasonic sensor 3, a transmitting module 4, a transmitting gating switch module 5, a receiving module 6, a receiving gating switch module 7, an AD conversion module 8, a central processing unit module 9, a display module 10, and a communication module 11. The three transceiver ultrasonic sensors 1, 2, and 3 are arranged in an equilateral triangle configuration. All three ultrasonic sensors 1, 2, and 3 are connected to the output of the transmitting gating switch module 5 and the input of the receiving gating switch module 7. The input of the transmitting gating switch module 5 is connected to the output of the transmitting module 4, and the input of the transmitting module 4 is connected to the central processing unit module 9. The receiving gating switch module 7 is connected to the receiving module 6, and the output of the receiving module 6 is connected to the input of the AD conversion module 8. The output of the AD conversion module 8 is connected to the central processing unit module 9. The central processing unit module 9 is connected to the display module 10 and the communication module 11, used to display and transmit the final measured wind speed and direction values.

[0110] like Figure 5 As shown, a method for measuring wind using a three-element ultrasonic transducer includes the following steps:

[0111] Step 1: After powering on the device, initialize each module;

[0112] Step Two: After initialization, the central processing unit module 9 controls the transmit gating switch module 5 to select ultrasonic sensor 1 as the transmitting probe. Simultaneously, the central processing unit module 9 controls the receive gating switch module 7 to select ultrasonic sensor 2 and ultrasonic sensor 3 as receiving probes. The transmitting signal of ultrasonic sensor 1 is:

[0113] x1(t) = s(t) + n(t)

[0114] In the formula: The signal represents the driving signal, A represents the amplitude of the ultrasonic wave transmitted signal, k represents the Gaussian coefficient, and ω = 2πf represents the ultrasonic wave angular frequency. Let n(t) represent the initial phase, and n(t) represent the additional noise in the transmitted signal.

[0115] The received signals of ultrasonic sensor 2 and ultrasonic sensor 3 are as follows:

[0116] y 1i (t)=s(t-τ 1i )+n 1i (t)

[0117] In the formula: τ represents the delayed signal, B represents the amplitude of the received ultrasonic signal, and τ represents the amplitude of the received ultrasonic signal. 1i This represents the propagation time of an ultrasonic wave from ultrasonic sensor 1 to the i-th ultrasonic sensor, where n is the propagation time. 1i (t) represents the noise added to the received signal;

[0118] Step 3: After receiving the signal, the receiving module 6 sends it to the AD conversion module 8, which then transmits it to the central processing module 9 for storage. The propagation time between the transmitted and received signals is then calculated using the quadratic correlation method, yielding the following result: Figure 3 The estimated propagation times of the ultrasonic waves shown are as follows: the estimated propagation time of the ultrasonic waves from ultrasonic sensor 1 to ultrasonic sensor 2 and ultrasonic sensor 3 is: The estimated propagation time of the ultrasonic wave from ultrasonic sensor 1 to ultrasonic sensor 3 is:

[0119] The specific method for determining the propagation time of ultrasound using the quadratic correlation method is as follows: Ultrasonic sensor 1 transmits, ultrasonic sensor 2 and ultrasonic sensor 3 receive:

[0120] Performing an autocorrelation operation on the transmitted signal x1(t), we obtain:

[0121] R xx (τ)=E[x1(t)x1(t-τ)]=R ss (τ)+Rsn (τ)+R ns (τ)+R nn (τ)

[0122] In the formula: R xx (τ) represents the autocorrelation function of the transmitted signal x1(t), E(·) represents the expectation, and R ss (τ) represents the autocorrelation function of the driving signal s(t), R sn (τ) represents the correlation function between the driving signal s(t) and the additional noise n(t) of the transmitted signal, R ns (τ) represents the correlation function between the additional noise n(t) of the transmitted signal and the driving signal s(t), R nn (τ) represents the autocorrelation function of the additional noise n(t) of the transmitted signal;

[0123] Since the driving signal s(t) is uncorrelated with the additional noise n(t) of the transmitted signal, the correlation function R sn (τ)=R ns Since (τ) = 0, we have:

[0124] R xx (τ)=R ss (τ)+R nn (τ)

[0125] Furthermore, since the emitted noise is white noise, its power spectral density is S. n (ω)=N0 (N0 is a constant), substituting the transmitted signal x1(t) into the autocorrelation function R xx In (τ), we get:

[0126]

[0127] In the above formula If the long-time integral is zero, then:

[0128]

[0129] In the formula: δ(τ) represents the Dirac function;

[0130] For the transmitted signal x1(t) and the received signal y 1i Performing cross-correlation on (t) yields:

[0131]

[0132] In the formula: Represents the transmitted signal x1(t) and the received signal y 1i The cross-correlation function between (t) and R0 ss (τ-τ 1i) represents the driving signal s(t) and the delayed signal s(t-τ). 1i Correlation functions between ) and R sn (τ-τ 1i ) represents the delayed signal s(t-τ) 1i The correlation function between the transmitted signal and the additional noise n(t) is given. This represents the noise n added to the driving signal s(t) and the received signal. 1i The correlation function between (t) The noise n(t) of the transmitted signal and the noise n of the received signal are represented by the following values. 1i The correlation function between (t);

[0133] Due to the additional noise n in the driving signal s(t) and the received signal 1i (t) is uncorrelated, and the delayed signal s(t-τ) 1i The transmitted signal's added noise n(t) is uncorrelated with the received signal's added noise n(t). 1i If (t) is uncorrelated, then the correlation function have:

[0134]

[0135] Receive signal y 1i (t)=s(t-τ 1i )+n 1i (t) Substitute into the cross-correlation function In the middle, we get:

[0136]

[0137] In the formula:

[0138] Observe the autocorrelation function R xx (τ) and cross-correlation function Both are functions of time delay τ. Treating them as new functions, we perform correlation operations on them again to obtain the quadratic correlation function:

[0139]

[0140] In the formula: R SS (κ-τ 1i ) represents and The correlation function between them, namely:

[0141]

[0142] R SN (κ) is The correlation function between N0δ(τ) and N0δ(τ) is:

[0143]

[0144] Then the quadratic correlation function R RR (κ) can be represented as:

[0145]

[0146] Because the quadratic correlation function is in κ=τ 1i The maximum value is taken at time, that is:

[0147] R RR (κ)≤R SS (0)+R SN (τ 1i )

[0148] Therefore, by finding its maximum value, the estimated propagation time of the ultrasonic signal from ultrasonic sensor 1 to ultrasonic sensor 2 and ultrasonic sensor 3 can be obtained:

[0149]

[0150] Step 4: The central processing unit module 9 controls the transmit gating switch module 5 to select ultrasonic sensor 2 as the transmitting probe. Simultaneously, the central processing unit module 9 controls the receive gating switch module 7 to select ultrasonic sensor 1 and ultrasonic sensor 3 as receiving probes. The transmitted signal of ultrasonic sensor 2 is:

[0151] x²(t) = s(t) + n(t)

[0152] In the formula: The signal represents the driving signal, A represents the amplitude of the ultrasonic wave transmitted signal, k represents the Gaussian coefficient, and ω = 2πf represents the ultrasonic wave angular frequency. Let n(t) represent the initial phase, and n(t) represent the additional noise in the transmitted signal.

[0153] The received signals of ultrasonic sensor 1 and ultrasonic sensor 3 are:

[0154] y 2i (t)=s(t-τ 2i )+n 2i (t)

[0155] In the formula: τ represents the delayed signal, B represents the amplitude of the received ultrasonic signal, and τ represents the amplitude of the received ultrasonic signal. 2i This represents the propagation time of an ultrasonic wave from ultrasonic sensor 2 to the i-th ultrasonic sensor, where n is the propagation time. 2i (t) represents the noise added to the received signal;

[0156] Step 5: The receiving module 6 sends the received signal to the AD conversion module 8, which then transmits it to the central processing module 9 for storage. The propagation time between the transmitted and received signals is then calculated using the quadratic correlation method, yielding the following result: Figure 3 The estimated propagation times of the ultrasonic waves shown are as follows: the estimated propagation time of the ultrasonic waves from ultrasonic sensor 2 to ultrasonic sensor 1 and ultrasonic sensor 3 is: The estimated propagation time of the ultrasonic wave from ultrasonic sensor 2 to ultrasonic sensor 3 is:

[0157] Step Six: The central processing unit module 9 controls the transmit gating switch module 5 to select ultrasonic sensor 3 as the transmitting probe. Simultaneously, the central processing unit module 9 controls the receive gating switch module 7 to select ultrasonic sensor 1 and ultrasonic sensor 2 as receiving probes. The transmitted signal of ultrasonic sensor 3 is:

[0158] x3(t) = s(t) + n(t)

[0159] In the formula: The signal represents the driving signal, A represents the amplitude of the ultrasonic wave transmitted signal, k represents the Gaussian coefficient, and ω = 2πf represents the ultrasonic wave angular frequency. Let n(t) represent the initial phase, and n(t) represent the additional noise in the transmitted signal.

[0160] The received signals of ultrasonic sensor 1 and ultrasonic sensor 2 are as follows:

[0161] y 3i (t)=s(t-τ 3i )+n 3i (t)

[0162] In the formula: τ represents the delayed signal, B represents the amplitude of the received ultrasonic signal, and τ represents the amplitude of the received ultrasonic signal. 3i This represents the propagation time of an ultrasonic wave from ultrasonic sensor 3 to the i-th ultrasonic sensor, where n is the time it takes for the ultrasonic wave to travel from ultrasonic sensor 3 to the i-th ultrasonic sensor. 3i (t) represents the additional noise in the received signal:

[0163] Step 7: The receiving module 6 sends the received signal to the AD conversion module 8, which then transmits it to the central processing module 9 for storage. The propagation time between the transmitted and received signals is then calculated using the quadratic correlation method, yielding the following result: Figure 3 The estimated propagation times of the ultrasonic waves from ultrasonic sensor 3 to ultrasonic sensor 1 and ultrasonic sensor 2 are shown below: the estimated propagation time of the ultrasonic wave from sensor 3 to sensor 1 is... The estimated propagation time of the ultrasonic wave from sensor 3 to sensor 2 is:

[0164] Step 8: Obtain the ultrasonic propagation time between each ultrasonic sensor by taking turns transmitting and receiving once, and then calculate the wind speed component in the direction of each ultrasonic sensor based on the measured ultrasonic propagation time.

[0165] From step three, the estimated propagation time of the ultrasonic wave from ultrasonic sensor 1 to ultrasonic sensor 2 is... From step five, we know that the propagation time of the ultrasonic wave from ultrasonic sensor 2 to ultrasonic sensor 1 is... The wind speed components along the direction from ultrasonic sensor 1 to ultrasonic sensor 2 can then be obtained as follows:

[0166]

[0167] In the formula: L represents the distance between ultrasonic sensors;

[0168] The estimated value of the propagation time of the ultrasonic wave from ultrasonic sensor 1 to ultrasonic sensor 3 in step three is... From step seven, we know that the propagation time of the ultrasonic wave from ultrasonic sensor 3 to ultrasonic sensor 1 is... Then the wind speed components in the directions from ultrasonic sensor 1 to ultrasonic sensor 3 can be obtained as follows:

[0169]

[0170] From step five, we can know that the estimated propagation time of the ultrasonic wave from ultrasonic sensor 2 to ultrasonic sensor 3 is [value missing]. From step seven, we know that the propagation time of the ultrasonic wave from ultrasonic sensor 3 to ultrasonic sensor 2 is... Then the wind speed component in the direction from ultrasonic sensor 3 to ultrasonic sensor 2 can be obtained as follows:

[0171]

[0172] Step 9: Calculate the actual wind speed and direction based on the wind speed components along the directions of each ultrasonic sensor. The wind speed components along the directions from ultrasonic sensor 1 to ultrasonic sensor 2 are V. 12 The wind speed component in the direction from ultrasonic sensor 1 to ultrasonic sensor 3 is V. 13 Based on wind speed and direction vector decomposition Figure 4 The relationship between the wind speed component and the actual wind speed and direction is as follows:

[0173] V 12 =Vcos(θ-π / 6)

[0174] V 13 =Vcos(θ+π / 6)

[0175] Solving the system of equations simultaneously yields a set of actual wind speeds V1 and wind directions θ1, which are as follows:

[0176]

[0177]

[0178] Wind speed component V from ultrasonic sensor 1 to ultrasonic sensor 2 12 The wind speed component V in the direction of ultrasonic sensor 2 to ultrasonic sensor 3. 32 Based on wind speed and direction vector decomposition Figure 4 The relationship between the wind speed component and the actual wind speed and direction is as follows:

[0179] V 12 =Vcos(θ-π / 6)

[0180] V 32 =Vsinθ

[0181] Solving the system of equations simultaneously yields another set of actual wind speeds V2 and wind directions θ2, which are:

[0182]

[0183]

[0184] Wind speed component V in the direction from ultrasonic sensor 1 to ultrasonic sensor 3 13 The wind speed component V in the direction from ultrasonic sensor 2 to ultrasonic sensor 3. 32 Based on wind speed and direction vector decomposition Figure 4 The relationship between the wind speed component and the actual wind speed and direction is as follows:

[0185] V 13 =Vcos(θ+π / 6)

[0186] V 32 =Vsinθ

[0187] Solving the system of equations simultaneously yields the actual wind speed V3 and wind direction θ3 for the third set of values:

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[0190] Step 10: Averaging the three sets of wind speed and direction values ​​yields the final wind speed and direction. This not only eliminates the obstruction effect caused by a single ultrasonic sensor blocking the signal, but also further improves noise suppression and the accuracy of wind speed and direction measurement. The final wind speed and direction are as follows:

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[0193] Step 11: Display the wind speed and direction values ​​from Step 10 through the display module 10 and output them through the communication module 11. Then return to Step 2 and repeat this process to obtain the wind speed and direction values ​​at different times.

[0194] The present invention will be further illustrated by the following experimental examples.

[0195] Experiment 1: Under wind speed V = 15 m / s and wind direction angle θ = 45°, 20 wind speed and direction measurement experiments were conducted. The wind speed measurement results are as follows: Figure 6 As shown, the wind direction measurement results are as follows: Figure 7 As shown, from Figure 6 and Figure 7 As can be seen from the data, the measured values ​​are basically consistent with the actual values, and the deviation of wind speed and direction is small, indicating that the method of the present invention can accurately measure wind speed and direction, and the method of the present invention is feasible.

[0196] Experiment 2: The wind speed was uniformly varied from 0 m / s to 60 m / s at 5 m / s intervals, and the wind direction angle was uniformly varied from 0° to 360° at 30° intervals. The experiment was conducted once at each interval, and the measurement results for different wind speeds are as follows: Figure 8 As shown, the measurement results for different wind directions are as follows: Figure 9 As shown, from Figure 8 and Figure 9 As can be seen from this, the method of the present invention can still accurately measure wind speed and wind direction when wind speed or wind direction changes, and the measurement results under different wind direction conditions are basically consistent, indicating that the method of the present invention can realize wide-range, full-angle domain wind vector measurement, and is not affected by the obstruction effect caused by the ultrasonic sensor blocking the wind.

Claims

1. A measurement method using a three-element ultrasonic anemometer with mutual-beam transmission, the three-element ultrasonic anemometer comprising an ultrasonic sensor one, an ultrasonic sensor two, an ultrasonic sensor three, a transmitting module, a transmitting gating switch module, a receiving module, a receiving gating switch module, an AD conversion module, a central processing unit module, a display module, and a communication module, wherein the three ultrasonic sensors are arranged in an equilateral triangle configuration, all three ultrasonic sensors are connected to the output terminal of the transmitting gating switch module and the input terminal of the receiving gating switch module, the input terminal of the transmitting gating switch module is connected to the output terminal of the transmitting module, the input terminal of the transmitting module is connected to the central processing unit module, the receiving gating switch module is connected to the receiving module, the output terminal of the receiving module is connected to the input terminal of the AD conversion module, the output terminal of the AD conversion module is connected to the central processing unit module, and the central processing unit module is connected to the display module and the communication module, for displaying and transmitting the finally measured wind speed and wind direction values, characterized in that... The measurement method includes the following steps: Step 1: After powering on the device, initialize each module; Step 2: After initialization, the central processing unit module controls the transmit gating switch module to select ultrasonic sensor one as the transmitting probe, and at the same time, the central processing unit module controls the receive gating switch module to select ultrasonic sensor two and ultrasonic sensor three as receiving probes. Step 3: After the receiving module sends the received signal to the AD conversion module, it transmits it to the central processing module for storage. Then, the propagation time between the transmitted and received signals is calculated using the quadratic correlation method. The estimated propagation times of the ultrasonic waves from ultrasonic sensor one to ultrasonic sensor two and ultrasonic sensor three are given: The estimated propagation time of the ultrasonic waves from ultrasonic sensor one to ultrasonic sensor two is... The estimated propagation time of the ultrasonic wave from ultrasonic sensor one to ultrasonic sensor three is: ; Step 4: The central processing unit module controls the transmit gating switch module to select ultrasonic sensor 2 as the transmitting probe, and at the same time, the central processing unit module controls the receive gating switch module to select ultrasonic sensor 1 and ultrasonic sensor 3 as the receiving probes. Step 5: The receiving module sends the received signal to the AD conversion module, then to the central processing module for storage. The propagation time between the transmitted and received signals is then calculated using the quadratic correlation method. Estimates are given for the propagation times of the ultrasonic waves from ultrasonic sensor 2 to ultrasonic sensor 1 and ultrasonic sensor 3: The estimated propagation time of the ultrasonic wave from ultrasonic sensor 2 to ultrasonic sensor 1 is... The estimated propagation time of the ultrasonic wave from ultrasonic sensor two to ultrasonic sensor three is... ; Step Six: The central processing unit module controls the transmit gating switch module to select ultrasonic sensor three as the transmitting probe, and at the same time, the central processing unit module controls the receive gating switch module to select ultrasonic sensor one and ultrasonic sensor two as receiving probes. Step 7: The receiving module sends the received signal to the AD conversion module, then to the central processing module for storage. The propagation time between the transmitted and received signals is then calculated using the quadratic correlation method. Estimates are given for the propagation times of the ultrasonic waves from ultrasonic sensor 3 to ultrasonic sensors 1 and 2: The estimated propagation time of the ultrasonic wave from sensor 3 to sensor 1 is... The estimated propagation time of the ultrasonic wave from sensor three to sensor two is: ; Step 8: Obtain the ultrasonic propagation time between each ultrasonic sensor by taking turns transmitting and receiving once, and then calculate the wind speed component in the direction of each ultrasonic sensor based on the measured ultrasonic propagation time. From step three, we can know that the estimated propagation time of the ultrasonic wave from ultrasonic sensor one to ultrasonic sensor two is... As shown in step five, the propagation time of the ultrasonic wave from ultrasonic sensor two to ultrasonic sensor one is... Then the wind speed components in the directions from ultrasonic sensor one to ultrasonic sensor two can be obtained as follows: ； In the formula: Indicates the distance between ultrasonic sensors; The estimated propagation time of the ultrasonic wave from ultrasonic sensor one to ultrasonic sensor three in step three is... As shown in step seven, the propagation time of the ultrasonic wave from ultrasonic sensor three to ultrasonic sensor one is... Then, the wind speed components in the three directions of the ultrasonic sensor can be obtained as follows: ； From step five, we can know that the estimated propagation time of the ultrasonic wave from ultrasonic sensor two to ultrasonic sensor three is... As shown in step seven, the propagation time of the ultrasonic wave from ultrasonic sensor three to ultrasonic sensor two is... Then, the wind speed components in the direction from ultrasonic sensor three to ultrasonic sensor two can be obtained as follows: ； Step Nine: Calculate the actual wind speed and direction based on the wind speed components along the directions of each ultrasonic sensor. The wind speed components along the directions from ultrasonic sensor one to ultrasonic sensor two are: The wind speed components in the three directions of the ultrasonic sensor are: The relationship between the wind speed component and the actual wind speed and direction is as follows: ； ； Solving the system of equations simultaneously yields a set of actual wind speeds. and wind direction They are respectively: ； ； Wind speed component from ultrasonic sensor one to ultrasonic sensor two Wind speed components in three directions from the ultrasonic sensor to the ultrasonic sensor The relationship between the wind speed component and the actual wind speed and direction is as follows: ； ； Solving the simultaneous equations yields another set of actual wind speeds. and wind direction They are respectively: ； ； Wind speed components from ultrasonic sensor one to ultrasonic sensor three directions Wind speed components in two to three directions of the ultrasonic sensor The relationship between the wind speed component and the actual wind speed and direction is as follows: ； ； Solving the simultaneous equations yields the actual wind speed for the third set. and wind direction They are respectively: ； ； Step 10: Averaging the three sets of wind speed and direction values ​​yields the final wind speed and direction. This not only eliminates the obstruction effect caused by a single ultrasonic sensor blocking the signal, but also further improves noise suppression and the accuracy of wind speed and direction measurement. The final wind speed and direction are as follows: ； ； Step 11: Display the wind speed and direction values ​​from Step 10 through the display module and output them through the communication module. Then return to Step 2. Repeat this process to obtain the wind speed and direction values ​​at different times.

2. The measurement method using a mutually resonant three-element ultrasonic wind measuring device according to claim 1, characterized in that: In step two, the transmitted signal of ultrasonic sensor one is: ； In the formula: Indicates the drive signal. Indicates the amplitude of the ultrasonic wave emitted signal. Represented as Gaussian coefficients, Indicates the angular frequency of the ultrasonic wave. Indicates the initial phase. This indicates additional noise in the transmitted signal; The received signals of ultrasonic sensor two and ultrasonic sensor three are as follows: ； In the formula: Indicates a delayed signal. Indicates the amplitude of the received ultrasonic signal. This indicates that the ultrasonic wave is reached by the ultrasonic sensor 1. The propagation time of an ultrasonic sensor This indicates that the received signal has added noise.

3. The measurement method using a mutually resonant three-element ultrasonic wind measuring device according to claim 2, characterized in that: In step three, the specific method for determining the ultrasonic wave propagation time using the quadratic correlation method is as follows: ultrasonic sensor one transmits, and ultrasonic sensor two and ultrasonic sensor three receive: For transmitted signals Performing autocorrelation calculations, we get: ； In the formula: Indicates the transmission signal The autocorrelation function, Expressing expectations, Indicates drive signal The autocorrelation function, Indicates drive signal Added noise to the transmitted signal The related functions between them Indicates additional noise in the transmitted signal With drive signal The related functions between them Indicates additional noise in the transmitted signal The autocorrelation function; Due to the drive signal Added noise to the transmitted signal If they are not correlated, then the correlation function is... ,have: ； Since the emitted noise is white noise, its power spectral density is: , If the value is constant, the signal will be transmitted. Substitute into the autocorrelation function In the middle, we get: ； In the above formula If the result of the long-time integral is zero, then we have: ； In the formula: , Represents the Dirac function; For transmitted signals With received signal Performing cross-correlation calculations, we get: ； In the formula: Indicates the transmission signal With received signal The cross-correlation function between them Indicates drive signal With delayed signal The related functions between them Indicates delayed signal Added noise to the transmitted signal The related functions between them Indicates drive signal Added noise to the received signal The related functions between them Indicates additional noise in the transmitted signal Added noise to the received signal Correlation functions between them; Due to the drive signal Added noise to the received signal Unrelated, delayed signal Added noise to the transmitted signal Unrelated, the transmitted signal has added noise. Added noise to the received signal If they are not correlated, then the correlation function is... ,have: ； Receive signal Substitute into the cross-correlation function In the middle, we get: ； In the formula: ; Observe the autocorrelation function and cross-correlation function Both are time delays Treating the function as a new function, we perform correlation operations on it again to obtain the quadratic correlation function: ； In the formula: Represented as and The correlation function between them, namely: ； for and The correlation function between them, namely: ； Then the quadratic correlation function It can be represented as: ； Because the quadratic correlation function is The maximum value is taken at time, that is: ； Therefore, by finding its maximum value, the estimated propagation time of the ultrasonic signal through ultrasonic sensor one to ultrasonic sensor two and ultrasonic sensor three can be obtained: 。 4. The measurement method using a mutually resonant three-element ultrasonic wind measuring device according to claim 1, characterized in that: In step four, the transmitted signal of ultrasonic sensor two is: ； In the formula: Indicates the drive signal. Indicates the amplitude of the ultrasonic wave emitted signal. Represented as Gaussian coefficients, Indicates the angular frequency of the ultrasonic wave. Indicates the initial phase. This indicates additional noise in the transmitted signal; The received signals of ultrasonic sensor one and ultrasonic sensor three are as follows: ； In the formula: Indicates a delayed signal. Indicates the amplitude of the received ultrasonic signal. This indicates that the ultrasonic wave reaches the second ultrasonic sensor. The propagation time of an ultrasonic sensor This indicates that the received signal has added noise.

5. The measurement method using a mutually resonant three-element ultrasonic wind measuring device according to claim 1, characterized in that: In step six, the transmitted signal of ultrasonic sensor three is: ； In the formula: Indicates the drive signal. Indicates the amplitude of the ultrasonic wave emitted signal. Represented as Gaussian coefficients, Indicates the angular frequency of the ultrasonic wave. Indicates the initial phase. This indicates additional noise in the transmitted signal; The received signals of ultrasonic sensor one and ultrasonic sensor two are: ； In the formula: Indicates a delayed signal. Indicates the amplitude of the received ultrasonic signal. This indicates that the ultrasonic wave reaches the third point via an ultrasonic sensor. The propagation time of an ultrasonic sensor This indicates that the received signal has added noise.

6. The measurement method using a mutually resonant three-element ultrasonic wind measuring device according to claim 1, characterized in that: Ultrasonic sensor 1, ultrasonic sensor 2, and ultrasonic sensor 3 are all transceiver-integrated ultrasonic sensors.

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