Hybrid Time-Frequency Estimation Of Time Of Flight (ToF) And Its Application In Ultrasonic Velocity Measurement Optimization

The Time-of-Flight(ToF)estimation is a technique for calculating the time required for ultrasonic waves to propagate between two points and has a wide range of applications.Due to factors such as multipath effects,crosstalk interference,and environmental changes influencing the propagation of ultrasonic waves,it is necessary to design robust and highly accurate estimation algorithms to address these challenges.In this paper,a ToF time-frequency hybrid estimation method is proposed for ultrasonic wave propagation characteristics in wind and water flow fields and is applied to ultrasonic speed measurement optimization.The main innovations of this paper are as follows:(1)Based on the propagation characteristics and physical properties of ultrasonic waves in wind fields,a ToF estimation algorithm for ultrasonic waves in time domain is proposed.This algorithm addresses the errors caused by the inevitable multipath effects and crosstalk interference noise during ultrasonic wave propagation and proposes an improved AR filter for processing the received ultrasonic signals.The ARAIC algorithm,based on the Akaike Information Criterion(AIC),is then designed for ToF estimation,and the effectiveness and superiority of this scheme are verified through simulation and experiments.(2)Considering the different propagation characteristics of ultrasonic waves in water flow fields and wind fields,the ultrasonic wave signals in water flow fields are remodeled.In response to the increased noise characteristics of ultrasonic signals in water,a combination of autoregressive(AR)filters and moving average(MA)filters is used to filter the received ultrasonic signals.The AIC is then used to evaluate the degree of fit between the filtered signal and the original signal,and the time corresponding to the minimum AIC value is the estimated ToF.Simulations and experiments show that this method can effectively improve the accuracy and stability of ToF estimation.(3)After completing the ToF estimation algorithm in the time domain,the ToF estimation algorithm is designed in the frequency domain.When estimating ToF in the frequency domain,the algorithm is affected by phase wrapping.To address this issue,the ARMA-AIC algorithm is first used for a rough ToF estimation,and then the received signal is shifted in the time domain according to the result.Finally,a frequency domain subsample estimation method is used for precise ToF estimation.To reduce the impact of noise,a power spectrum weighted average method is employed for frequency domain subsample interpolation.Comparing the bias error and random error of the estimation shows that this method can improve the accuracy and repeatability of the estimation.In order to improve the accuracy of wind speed and water flow speed measurements,various intelligent optimization algorithms are compared.Due to the faster convergence speed and higher accuracy of the Beetle Antennae Search optimization algorithm(BAS),it is chosen to optimize the ultrasonic speed measurement results.The relationship between wind speed or water flow speed and the estimated ToF is transformed into a constrained optimization problem,and the BASWPT algorithm is used for optimization.The results show that,through reasonable algorithm parameter settings,the measurement accuracy of wind speed or water flow speed is improved after using BAS optimization,and the BAS algorithm has faster convergence and calculation speed.The algorithm design and improvement have enhanced the speed measurement accuracy of the ultrasonic speed measurement system.With the Arduino UNO development board as the core,a suitable ultrasonic transducer is chosen,and the ultrasonic receiving circuit and transmitting circuit are designed.The entire ultrasonic speed measurement system is built and used to verify the aforementioned ToF estimation algorithms.Through physical and simulation verification,the system can effectively improve the accuracy and stability of speed measurement through algorithm and circuit design.