阅读说明：本技术 一种高精度户用超声波水表抗干扰滤波方法及设备 (Anti-interference filtering method and device for high-precision household ultrasonic water meter ) 是由 朱林海 陈剑 陈钇安 刘倩 李潇 于 2021-09-17 设计创作，主要内容包括：一种高精度户用超声波水表抗干扰滤波方法包括以下步骤,采集停止用水时顺流与逆流的时差信号,计算相邻采样点时差信号之间斜率的绝对值,计算时差信号斜率绝对值的均值K-(j平均),选取合适判定阀值δ,若K-(j平均)<δ则使用改进型平滑滤波,若K-(j平均)>δ,则使用卡尔曼滤波,计算整个采样时间T内滤波后的最终时差信号ΔT-(final),采用ΔT-(final)参与补偿或抵消非零流量的计算。一种高精度户用超声波水表,该设备采用前述高精度户用超声波水表抗干扰滤波方法进行抗干扰滤波。该方法能够实时、有效的滤除户用超声波水表在使用过程中流量测量受到气泡、零点漂移、杂质等干扰的影响,减小户用超声波水表流量测量误差。(An anti-interference filtering method for the ultrasonic water meter used at high-precision family includes such steps as collecting the downstream and upstream time difference signals, calculating the absolute value of slope between adjacent sampling points, and calculating the mean value K of slope absolute values j average Selecting a proper judgment threshold value delta if K j average <Delta is then smoothed using modified smoothing if K j average >Delta, calculating the final time difference signal delta T after filtering within the whole sampling time T by using Kalman filtering final By using Δ T final Participate in the calculation of compensating or canceling the non-zero flow. The utility model provides a high accuracy ultrasonic water meter for family, this equipment adopts aforementioned high accuracy ultrasonic water meter anti-interference filtering method for family to carry out anti-interference filtering. The method can effectively filter the influence of the interference of bubbles, zero drift, impurities and the like on the flow measurement of the household ultrasonic water meter in the using process in real time, and reduce the influence of the interference of the household ultrasonic water meter on the household ultrasonic water meter in the using processAnd measuring errors by using an ultrasonic water meter.)

1. An anti-interference filtering method for a high-precision household ultrasonic water meter is characterized by comprising the following steps:

s1, when the user stops using water, collecting the time difference signal delta t between forward flow and backward flow_i,j，

Δt_i,jThe time difference signal is acquired by the ith sampling point in the jth unit sampling period, i is 1, 2, theA unit sampling period;

s2, calculating the absolute value K of the slope between the time difference signals of adjacent sampling points_i-1,j，K_i-1,j＝|(Δt_i,j-Δt_i-1,j)/T″|；

S3, calculating the average value K of the absolute value of the slope of the time difference signal of the sampling point in the jth unit sampling period_{j average}，

S4, selecting a proper judgment threshold value delta;

s5, if K_{j average}<Delta, filtering the time difference signal of the sampling point in the jth unit sampling period by using improved smooth filtering to obtain delta t_p,jAnd let the filtered time difference signal delta T in the jth unit sampling period_j＝Δt_p,j(ii) a If K_{j average}>Delta, filtering the time difference signal of the sampling point in the jth unit sampling period by using Kalman filtering to obtain delta t_k,jAnd let the filtered time difference signal delta T in the jth unit sampling period_j＝Δt_k,j；

S6, calculating the final time difference signal after filtering in the whole sampling time T

S7, when the user starts to use water, adopting the delta T obtained by the time interval that the user stops using water before starting to use water_finalParticipate in the calculation of compensating or canceling the non-zero flow.

2. The anti-interference filtering method for the ultrasonic water meter for the high-precision user according to claim 1, wherein the step of selecting the proper decision threshold δ in step S4 comprises:

s41, if K_{j average}<1, taking delta as 1;

s42, if K_{j average}>5, taking delta to be 5;

s43, if 1 is less than or equal to K_{j average}If the value is less than or equal to 5, the self-adaptive adjustment is carried outK in jth unit sampling period_{j average}So that the filtered zero flow error value is minimized.

3. The anti-interference filtering method for the ultrasonic water meter for the high-precision user according to claim 2, wherein the step S43 is implemented by adaptively adjusting K in the jth unit sampling period_{j average}Such that the step of minimizing the filtered zero flow error value comprises:

s431 at [1,5 ]]And (4) assigning the judgment threshold value delta according to the step length s to obtain delta_t1+ sx (t-1), wherein t 1, 2,<s<5, Q is not more thanAn integer of (d);

s432, according to step S5, each judgment threshold value delta is calculated_tCorresponding filtered time difference signal delta T in jth unit sampling period_t,j；

S433, calculating each judgment threshold value delta_tMean value of absolute values of corresponding time difference signals

S434, converting the | Delta T_t|_AVGThe minimum value is used as the optimal decision threshold value delta.

4. The anti-interference filtering method for the ultrasonic water meter for the high-precision users according to claim 1, wherein the step of improved smooth filtering in step S5 comprises:

s511, finding out all the n time difference signals delta t in the jth unit sampling period_i,jMaximum value of (a) t_max,jAnd a minimum value Δ t_min,j；

S512, according to the formulaPerforming improved smoothing filtering to obtain the jth unit after filteringTime difference signal deltat within a sampling period_p,j。

5. The anti-interference filtering method for the ultrasonic water meter for the high-precision user according to claim 1, wherein the kalman filtering step in step S5 includes:

s521, introducing measurement values of a linear system and a system according to a time difference signal of the current time in a jth unit sampling period, and establishing a model:

Δt(k)＝AΔt(k-1)+BU(k)+W(k)，

Z(k)＝HΔt(k)+t(k)，

wherein v (k) represents the system state at time k, u (k) represents the control quantity of the system at time k, A, B represents the system parameter, z (k) represents the measured value at time k, H represents the parameter of the measurement system, w (k), and t (k) represents the process and the noise of the measurement;

s522, predict the state at time k:

Δt(k|k-1)＝AΔt(k-1|k-1)+BU(k)，

wherein A, B represents system parameters, for a multi-model system, A, B is a matrix, Δ t (k | k-1) is the result of prediction of the previous state, Δ t (k-1| k-1) is the optimal predicted value at the previous moment, and U (k) is the controlled variable of the current state;

s523, updating the covariance of Δ t (k | k-1):

P(k|k-1)＝AP(k-1|k-1)A^T+Q，

where P (k | k-1) is the covariance for Δ t (k | k-1), P (k-1| k-1) is the covariance for Δ t (k-1| k-1), A^TIs the transposed matrix of A, Q is the system noise;

s524, calculating a Kg value:

Kg(k)＝P(k|k-1)H^T/(HP(k|k-1)H^T+R)，

wherein Kg is Kalman gain, R is noise in the measurement process, and H is a parameter of the measurement system;

and S525, calculating an optimization estimated value:

Δt(k|k)＝Δt(k|k-1)+Kg(k)(Z(k)-HΔt(k|k-1))，

where Δ t (k | k) is the filtered time difference signal Δ t in the jth unit sampling period_k,jZ (k) is the system measurement at time k;

s526, updates the covariance at time Δ t (k | k) k:

P(k|k)＝(1-Kg(k)H)P(k|k-1)。

6. the anti-interference filtering method for the high-precision household ultrasonic water meter according to claim 3, wherein the step length S in step S431 takes a value of 0.5.

7. The anti-interference filtering method for the ultrasonic water meter used by the user with high precision as claimed in claim 1, wherein the step S7 is implemented by using Δ T obtained from the time period when the user stops using water when the user starts using water_finalInvolving calculation of compensating or counteracting non-zero flows, Δ T_finalThe final time difference signal after filtering within the last sampling time T before starting to use water is used.

8. The anti-interference filtering method for the ultrasonic water meter used by the user with high precision as claimed in claim 1, wherein the step S7 is implemented by using Δ T obtained from the time period when the user stops using water when the user starts using water_finalThe step of participating in the calculation of the compensation or cancellation of the non-zero flow comprises:

s71, if Δ T_final>0, when the non-zero flow calculation is carried out, the time difference signal delta t is transmitted_cMinus Δ T_finalPost-calculation instantaneous flow: Δ t ═ Δ t_c-ΔT_finalΔ t is the difference between the offset and non-zero flow rates, Δ t_cThe real-time measurement value is a non-zero flow time difference value;

s72, if Δ T_final<0, when the non-zero flow calculation is carried out, the time difference signal delta t is transmitted_cPlus Δ T_finalCalculating the instantaneous flow rate after the absolute value of: Δ t ═ Δ t_c+|ΔT_finalI, Δ t is the compensated non-zero flow time difference, Δ t_cThe real-time measurement value is a non-zero flow time difference value.

9. A high-precision household ultrasonic water meter device, characterized in that the anti-interference filtering method of the high-precision household ultrasonic water meter according to any one of claims 1 to 8 is adopted for anti-interference filtering.

Technical Field

The invention relates to the technical field of intelligent metering, in particular to an interference filtering method and device for a high-precision household ultrasonic water meter.

Background

Compared with the traditional mechanical water meter, the ultrasonic water meter has the advantages of no mechanical transmission, wide range ratio, low pressure loss and the like, and is the fully electronic direction of the water meter. The household ultrasonic water meter realizes the miniaturization of the ultrasonic water meter, popularizes the water consumption of residents, and brings technical innovation and development to the water supply metering industry. However, the household ultrasonic water meter has the outstanding problem of large flow measurement error due to small caliber, short ultrasonic flight time, and the influence of interference of bubbles, zero drift, impurities and the like on the flow.

In order to solve the problem of large flow measurement error of a household ultrasonic water meter, various filtering methods are available at present: wavelet denoising is a common time-frequency localization analysis method, has the characteristic of multi-resolution analysis, time windows and frequency windows can be changed, local characteristics of signals can be represented in two time-frequency domains, and high-frequency parts can be removed through decomposition. The smooth filtering method mechanically averages several data, and can meet the application of low power consumption, but abrupt noise can cause large change of the whole data, and the real-time performance is poor due to the need of multiple sampling by the ultrasonic water meter, and particularly, the data is easy to lose when the flow rate changes rapidly. The BP neural network algorithm has low convergence speed, long iteration time and large calculated amount, and cannot meet the requirement of the flow measurement instantaneity of the household water meter. The filtering processing method is mainly used for filtering in the operation process of the household ultrasonic water meter so as to reduce the flow measurement error, and the flow measurement error value is mainly obtained by comparing with the standard data of a laboratory. The environment of the ultrasonic water meter used by a user is complex and changeable, and the situation that the environment is the same as the laboratory operation environment is difficult to guarantee, so that the flow measurement error value cannot be accurately calibrated.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method which can effectively filter the influence of the interference of bubbles, zero drift, impurities and the like on the flow measurement of a household ultrasonic water meter in the using process in real time, reduce the flow measurement error of the household ultrasonic water meter and provide high-precision household ultrasonic water meter equipment adopting the method.

In order to solve the technical problem, the invention provides an anti-interference filtering method for a high-precision household ultrasonic water meter, which comprises the following steps:

step S1, when the user stops using water, collecting the time difference signal delta t of forward flow and reverse flow_i,j，Δt_i,jThe time difference signal is acquired by the ith sampling point in the jth unit sampling period, i is 1, 2, theA unit sampling period;

step S2, calculating the absolute value K of the slope between the time difference signals of adjacent sampling points_i-1,j，K_i-1,j＝|(Δt_i,j-Δt_i-1,j)/T″|；

Step S3, calculating the average value K of the absolute value of the slope of the time difference signal of the sampling point in the jth unit sampling period_{j average}，

Step S4, selecting a proper judgment threshold value delta;

step S5, if K_{j average}<Delta, filtering the time difference signal of the sampling point in the jth unit sampling period by using improved smooth filtering to obtain delta t_p,jAnd let the filtered time difference signal delta T in the jth unit sampling period_j＝Δt_p,j(ii) a If K_{j average}>Delta, filtering the time difference signal of the sampling point in the jth unit sampling period by using Kalman filtering to obtain delta t_k,jAnd let the filtered time difference signal delta T in the jth unit sampling period_j＝Δt_k,j；

Step S6, calculating the final time difference signal after filtering in the whole sampling time T

Step S7, when the user starts to use water, adopting the delta T of the time period that the user stops using water before starting to use water_finalParticipate in the calculation of compensating or canceling the non-zero flow.

Further, the step of selecting the appropriate decision threshold δ in step S4 includes:

step S41, if K_{j average}<1, taking delta as 1;

step S42, if K_{j average}>5, taking delta to be 5;

step S43, if K is more than or equal to 1_{j average}If the sampling rate is less than or equal to 5, adaptively adjusting K in the jth unit sampling period_{j average}So that the filtered zero flow error value is minimized.

Further, in step S43, the adaptive adjustment of K in the jth unit sampling period_{j average}Such that the step of minimizing the filtered zero flow error value comprises:

step S431, at [1,5 ]]And (4) assigning the judgment threshold value delta according to the step length s to obtain delta_t1+ sx (t-1), wherein t 1, 2,<s<5, Q is not more thanAn integer of (d);

in step S432, each determination threshold δ is calculated in accordance with step S5_tCorresponding filtered time difference signal delta T in jth unit sampling period_t,j；

Step S433, calculate each determination threshold value delta_tMean value of absolute values of corresponding time difference signals

Step S434, converting the | Delta T_t|_AVGThe minimum value is used as the optimal decision threshold value delta.

Further, the step of modified smoothing filtering in step S5 includes:

step S511, finding out all n time difference signals delta t in the jth unit sampling period_i,jMaximum value of (a) t_max,jAnd a minimum value Δ t_min,j；

Step S512, according to the formulaCarrying out improved smooth filtering to obtain a time difference signal delta t in the jth unit sampling period after filtering_p,j。

Further, the kalman filtering step in step S5 includes:

step S521, in the jth unit sampling period, according to the time difference signal at the current moment, introducing the measurement values of the linear system and the system, and establishing a model:

Δt(k)＝AΔt(k-1)+BU(k)+W(k)，

Z(k)＝HΔt(k)+t(k)，

wherein v (k) represents the system state at time k, u (k) represents the control quantity of the system at time k, A, B represents the system parameter, z (k) represents the measured value at time k, H represents the parameter of the measurement system, w (k), and t (k) represents the process and the noise of the measurement;

in step S522, the predicted k-time state:

Δt(k|k-1)＝AΔt(k-1|k-1)+BU(k)，

wherein A, B represents system parameters, for a multi-model system, A, B is a matrix, Δ t (k | k-1) is the result of prediction of the previous state, Δ t (k-1| k-1) is the optimal predicted value at the previous moment, and U (k) is the controlled variable of the current state;

step S523, update the covariance of Δ t (k | k-1):

P(k|k-1)＝AP(k-1|k-1)A^T+Q，

where P (k | k-1) is the covariance for Δ t (k | k-1), P (k-1| k-1) is the covariance for Δ t (k-1| k-1), A^TIs the transposed matrix of A, Q is the system noise;

step S524, calculate Kg value:

Kg(k)＝P(k|k-1)H^T/(HP(k|k-1)H^T+R)，

wherein Kg is Kalman gain, R is noise in the measurement process, and H is a parameter of the measurement system;

step S525, calculating an optimization estimate:

Δt(k|k)＝Δt(k|k-1)+Kg(k)(Z(k)-HΔt(k|k-1))，

where Δ t (k | k) is the filtered time difference signal Δ t in the jth unit sampling period_k,jZ (k) is the system measurement at time k;

in step S526, the covariance at time Δ t (k | k) at k is updated:

P(k|k)＝(1-Kg(k)H)P(k|k-1)。

further, the step length S in step S431 is 0.5.

Further, when the user starts to use the water as described in step S7, Δ T obtained by the time period during which the user stops using the water is used_finalInvolving calculation of compensating or counteracting non-zero flows, Δ T_finalThe final time difference signal after filtering within the last sampling time T before starting to use water is used.

Further, when the user starts to use the water as described in step S7, Δ T obtained by the time period during which the user stops using the water is used_finalThe step of participating in the calculation of the compensation or cancellation of the non-zero flow comprises:

step S71, if Δ T_final>0, when the non-zero flow calculation is carried out, the time difference signal delta t is transmitted_cMinus Δ T_finalPost-calculation instantaneous flow: Δ t ═ Δ t_c-ΔT_finalΔ t is the difference between the offset and non-zero flow rates, Δ t_cThe real-time measurement value is a non-zero flow time difference value;

step S72, if Δ T_final<0, when the non-zero flow calculation is carried out, the time difference signal delta t is transmitted_cPlus Δ T_finalCalculating the instantaneous flow rate after the absolute value of: Δ t ═ Δ t_c+|ΔT_finalI, Δ t is the compensated non-zero flow time difference, Δ t_cThe real-time measurement value is a non-zero flow time difference value.

The invention also provides high-precision household ultrasonic water meter equipment which adopts the high-precision household ultrasonic water meter anti-interference filtering method to perform anti-interference filtering.

The invention has the beneficial effects that:

the method is characterized in that according to the water consumption habit of a resident household water meter, most of time is in zero flow, and because the interference of bubbles, zero drift, impurities and the like does not change too much when a user uses water and when the user does not use water, the method has the characteristic of keeping, a time difference signal caused by the interference in the zero flow condition is obtained by collecting downstream and upstream time difference signals when the user does not use water, the absolute value of the slope of the time difference signal of two adjacent points is calculated according to the time difference signal, an improved smoothing filtering and Kalman filtering method is automatically switched according to the comparison result of the average value of the absolute values of the slope of the time difference signal of the adjacent sampling points in a sampling period and a set judgment threshold, when the average value of the absolute values of the slope of the time difference signal of the adjacent sampling points in the sampling period is smaller than the judgment threshold, the improved smoothing filtering is adopted to filter the time difference signal, the improved smoothing filtering removes the maximum value and the minimum value of the time difference, the average operation of the intermediate numbers is adopted, so that the phenomenon that integral data is larger due to abrupt noise is avoided; when the mean value of the absolute value of the time difference signal slope of the adjacent sampling points in the sampling period is larger than the judgment threshold value, filtering the time difference signal by adopting Kalman filtering, and having good real-time performance; the two algorithms are mutually matched to calculate the time difference of compensation or offset and participate in the calculation of subsequent non-zero flow.

Most of the existing ultrasonic water meter filtering algorithms are used for filtering in a zero-flow measurement running state of a water meter, filtering parameters are preset according to the value of a test bed body and cannot be adjusted in real time according to the actual condition of the water meter using field, and due to the fact that the actual using environment of the water meter is inconsistent with the test bed body, the filtering effect is poor, and the error of flow measurement of the ultrasonic water meter is large. The anti-interference filtering method disclosed by the invention monitors the time difference signal of the zero flow of the user constantly, starts correction once the time difference signal of the zero flow of the user occurs, and updates the correction value of the zero flow constantly for participating in subsequent normal non-zero flow measurement calculation, thereby effectively solving the anti-interference problem of the ultrasonic water meter for the user and improving the flow measurement precision of the ultrasonic water meter for the user.

Drawings

Fig. 1 is a flow chart of an embodiment of an anti-interference filtering method for a high-precision household ultrasonic water meter according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It should be further understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

As shown in fig. 1, an anti-interference filtering method for a high-precision household ultrasonic water meter includes the following steps:

step S1, when the user stops using water, collecting the time difference signal delta t of forward flow and reverse flow_i,j，Δt_i,jThe time difference signal is acquired by the ith sampling point in the jth unit sampling period, i is 1, 2, theA unit sampling period;

step S2, calculating the absolute value K of the slope between the time difference signals of adjacent sampling points_i-1,j，K_i-1,j＝|(Δt_i,j-Δt_i-1,j)/T″|；

Step S3, calculating the average value K of the absolute value of the slope of the time difference signal of the sampling point in the jth unit sampling period_{j average}，

Step S4, selecting an appropriate decision threshold δ:

step S41, if K_{j average}<1, taking delta as 1;

step S42, if K_{j average}>5, taking delta to be 5;

step S43, if K is more than or equal to 1_{j average}If the sampling rate is less than or equal to 5, adaptively adjusting K in the jth unit sampling period_{j average}So that the filtered zero flow error value is the smallest:

step S431, at [1,5 ]]And (4) assigning the judgment threshold value delta according to the step length s to obtain delta_t1+ sx (t-1), wherein t is 1, 2,. and Q, the step length s is 0.5, and Q is 9;

in step S432, each determination threshold δ is calculated in accordance with step S5_tCorresponding filtered time difference signal delta T in jth unit sampling period_t,j；

Step S433, calculate each determination threshold value delta_tMean value of absolute values of corresponding time difference signals

Step S434, converting the | Delta T_t|_AVGThe minimum value is used as the optimal decision threshold value delta.

Step S5, if K_{j average}<Delta, filtering the time difference signal of the sampling point in the jth unit sampling period by using improved smooth filtering to obtain delta t_p,jAnd let the filtered time difference signal delta T in the jth unit sampling period_j＝Δt_p,j(ii) a If K_{j average}>Delta, filtering the time difference signal of the sampling point in the jth unit sampling period by using Kalman filtering to obtain delta t_k,jAnd let the filtered time difference signal delta T in the jth unit sampling period_j＝Δt_k,j：

The improved smoothing filtering step comprises the following steps:

step S511, finding out all n time difference signals delta t in the jth unit sampling period_i,jMaximum value of (a) t_max,jAnd a minimum value Δ t_min,j；

Step S512, according to the formulaCarrying out improved smooth filtering to obtain a time difference signal delta t in the jth unit sampling period after filtering_p,j。

The Kalman filtering step is as follows:

step S521, in the jth unit sampling period, according to the time difference signal at the current moment, introducing the measurement values of the linear system and the system, and establishing a model:

Δt(k)＝AΔt(k-1)+BU(k)+W(k)，

Z(k)＝HΔt(k)+t(k)，

wherein v (k) represents the system state at time k, u (k) represents the control quantity of the system at time k, A, B represents the system parameter, z (k) represents the measured value at time k, H represents the parameter of the measurement system, w (k), and t (k) represents the process and the noise of the measurement;

in step S522, the predicted k-time state:

Δt(k|k-1)＝AΔt(k-1|k-1)+BU(k)，

wherein A, B represents system parameters, for a multi-model system, A, B is a matrix, Δ t (k | k-1) is the result of prediction of the previous state, Δ t (k-1| k-1) is the optimal predicted value at the previous moment, and U (k) is the controlled variable of the current state;

step S523, update the covariance of Δ t (k | k-1):

P(k|k-1)＝AP(k-1|k-1)A^T+Q，

where P (k | k-1) is the covariance for Δ t (k | k-1), P (k-1| k-1) is the covariance for Δ t (k-1| k-1), A^TIs the transposed matrix of A, Q is the system noise;

step S524, calculate Kg value:

Kg(k)＝P(k|k-1)H^T/(HP(k|k-1)H^T+R)，

wherein Kg is Kalman gain, R is noise in the measurement process, and H is a parameter of the measurement system;

step S525, calculating an optimization estimate:

Δt(k|k)＝Δt(k|k-1)+Kg(k)(Z(k)-HΔt(k|k-1))，

where Δ t (k | k) is the filtered time difference signal Δ t in the jth unit sampling period_k,jZ (k) is the system measurement at time k;

in step S526, the covariance at time Δ t (k | k) at k is updated:

P(k|k)＝(1-Kg(k)H)P(k|k-1)。

step S6, calculating the final time difference signal after filtering in the whole sampling time T

Step S7, when the user starts to use water, the final time difference signal delta T filtered in the last sampling time T before the water use is started is adopted_finalParticipate in the calculation of compensating or canceling non-zero flow:

step S71, if Δ T_final>0, when the non-zero flow calculation is carried out, the time difference signal delta t is transmitted_cMinus Δ T_finalPost-calculation instantaneous flow: Δ t ═ Δ t_c-ΔT_finalΔ t is the difference between the offset and non-zero flow rates, Δ t_cThe real-time measurement value is a non-zero flow time difference value;

step S72, if Δ T_final<0, when the non-zero flow calculation is carried out, the time difference signal delta t is transmitted_cPlus Δ T_finalCalculating the instantaneous flow rate after the absolute value of: Δ t ═ Δ t_c+|ΔT_finalI, Δ t is the compensated non-zero flow time difference, Δ t_cThe real-time measurement value is a non-zero flow time difference value.

The invention also provides high-precision household ultrasonic water meter equipment which adopts the high-precision household ultrasonic water meter anti-interference filtering method to perform anti-interference filtering and performs the test of accumulated flow errors.

In view of the fact that the error of the ultrasonic water meter is the largest under the conditions of small flow and zero flow, the test of the flow measurement error before and after filtering is only carried out under the condition of small flow in the embodiment: referring to' JJG-162-:

the test result shows that the accumulated flow error after filtering is basically controlled within +/-2 percent and is qualified, while the error before filtering is large and mostly exceeds the error of small flow +/-5 percent.

The embodiment of the invention can carry out sequence adjustment, combination and deletion according to actual needs.

The embodiments describe the present invention in detail, and the specific embodiments are applied to illustrate the principle and the implementation of the present invention, and the above embodiments are only used to help understand the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.