Wind Speed And Direction Measurement Method Based On Ultrasonic Sensor Array And Multiple Signal Classification Algorithm

As an important natural phenomenon,wind has been widely used in daily life.It is very important to measure wind speed and direction accurately in railway,aviation,navigation,military affairs and meteorology,etc.Due to the range of measurable wind speed is finite,and many disadvantages,such as the mechanical abrasion,short service life,high maintenance cost and low accuracy,the traditional wind instruments have gradually been replaced by ultrasonic anemometer,which has the advantages of simple structure,wide measuring range,high measuring speed and high accuracy.The most widely used method in ultrasonic wind measurement theory is time difference method,which utilizes the difference of propagation time in downwind and upwind to measure wind speed.The domestic and foreign scholars' research is also carried out around the time difference method,the measurement accuracy of the time difference method entirely depends on the measurement of ultrasonic transmission time difference.In particular,in the case of strong electromagnetic interference or low signal-to-noise ratio,the time measurement of the ultrasonic transmission would become difficult or even lead to failure.Array signal processing method can effectively suppress the noise in complex environment.However,the application of the array signal processing theory for the study of meteorological instruments is rare,especially for the ultrasonic wind measurement research.This paper combines the advantage of array signal processing with the multiple signal classification(MUSIC)algorithm to estimate the wind speed and wind direction.The main contents of this paper are as follows:1.This paper designs a kind of arc ultrasonic sensor array structure.On this basis,the mathematical model of the near-field array receiving data is established,and thearray flow pattern vector is deduced.On the basic idea of the MUSIC algorithm,the wind speed and direction information is estimated by searching the spectral peak,according to the range and resolution of the wind speed and wind direction.2.This paper analyzes the performance and problems of the method of estimating the wind speed and direction by combining the arc array with the MUSIC algorithm.The formula of wind speed and direction estimation variance is deduced,and it can be used for any array structure,the Cramer-Rao bound formula is deduced too.Based on the analysis of the variance and the array ambiguity problem,the defect of the uniform linear array is discussed.Then,the range of wind direction,array ambiguity and resolution are discussed in detail.The feasibility of the method and performance are verified by the simulation experiments.3.According to the range and the resolution of wind speed and direction to be estimated,the variance is calculated by using the derived formula.The accuracy of the method is explained in theory.The large part of the estimation variance is analysised in particular.The derived formula of variance has a high application value in the analysis of the accuracy of this method.4.Verify the proposed method by building a hardware experimental platform.Firstly,the whole structure and the components of the hardware experiment platform are described in detail.The wind speed calibration is carried out by using Gill.Then,this paper explains how to deal with the data in the practical application of the hardware experiment platform.Finally,the experimental results in the wind tunnel and the causes of the errors are analyzed.The feasibility and stability of the method are proved.