Method For Ultrasonic Wind Measurement In The Complex Noise Background

Wind is closely related to people’s daily lives,and wind speed and direction measurements play an important role in various fields such as military,meteorology,navigation,and aviation.With the increasing demands for wind measurement,ultrasonic anemometry has emerged as a hot topic among researchers due to its advantages of low latency,high accuracy,wide range,and low starting wind speed.Time of flight method is the most commonly used ultrasonic anemometry method,which relies on accurate estimation of time delay.Cross-correlation method,as the easiest hardware implementation for ultrasonic time delay estimation,requires spectral peak search to obtain the time delay,resulting in higher latency.Additionally,the background noise present in the wind measurement environment can also affect the accuracy of the measurement results.Existing methods generally assume that the background noise follows a Gaussian distribution.However,research has found that the background noise in real-world environments is often more complex and contains nonGaussian components such as impulsive noise.The current approach using Fractional Low Order Statistics(FLOS)to handle impulsive noise cannot completely suppress the noise,leading to less than ideal wind measurement results.In order to achieve high-precision wind measurement in complex noise backgrounds,it is necessary to propose a measurement method that can effectively suppress the noise and has lower latency.To this end,this paper carries out the following work:1.Analyze and compare the advantages and disadvantages of the Time-of-Flight(TOF)method and the phase difference method,and determine the basic wind measurement method used in this paper.A positive triangular shooting ultrasonic transducer array is adopted,and the wind vector synthesis method of the array is derived,with calibration of the wind direction angle,and finally,a mathematical model of the transmit-receive signals is provided.2.To address the shortcomings of the Cross-Correlation(CC)method,such as high computational complexity,a novel ultrasonic anemometry method based on orthogonal lockin amplification is proposed.A digital orthogonal lock-in amplifier is designed,and the algorithm performance is validated through simulation experiments.3.For the impulsive noise components present in complex noise backgrounds,a new ultrasonic anemometry method based on fractional-order correlation function is proposed.The fractional-order mean and fractional-order correlation function are first defined.Then,the properties of the fractional-order correlation function in stationary random processes are derived.The principle of estimating time delay using the fractional-order correlation function in complex noise backgrounds is analyzed.Finally,the algorithm performance is evaluated through simulation experiments.4.A prototype of the ultrasonic anemometer is constructed,and real-world experiments are conducted.The overall hardware framework of the anemometer is defined,and the design of various hardware modules is carried out.Subsequently,the software system and the host computer for the prototype are designed.Finally,the anemometer is subjected to windless and windy tests,and the experimental results are analyzed.