Research And Implementation Of High Precision Wind Vector Measurement System Based On Time Difference Method

Compared with other measurement methods,the ultrasonic wind vector measurement method has the advantages of large range,no starting wind speed,no mechanical wear,etc.However,the existing ultrasonic anemometer in China has large measurement error and cannot accurately measure under low wind speed scenes such as mines.In this paper,the digital ultrasonic wind vector measuring instrument is developed based on the ultrasonic time difference method,which can realize high-precision measurement of wind vector.Alpha noise can better represent the noise in the actual environment than Gaussian noise.The delay estimation algorithm with better transit time detection accuracy under Gaussian noise deteriorates when interfered by Alpha noise,which cannot meet the needs of this topic.Aiming at this problem,the normalized cross-correlation method is applied to the ultrasonic transit time detection and simulation experiments are performed.The results show that the delay estimation error based on the normalized cross-correlation algorithm under Alpha noise is less than 0.3.us,can meet the expected technical indicators of this subject.The existing application method of the delay estimation algorithm in the field of ultrasonic transit time detection is the reference signal method,but the ultrasonic signal received in the actual environment will be subjected to different interference,resulting in weaken correlation with the reference signal,increased error of the delay estimation result at the same time.In response to this problem,this paper proposes a method of using the reflected signal as a reference signal.The method uses the reflected signal and the initial received signal to estimate the time delay,and the comparison experiment proves that the method can improve the delay estimation accuracy of the system in the actual environment compared with the reference signal method.The wind vector measurement system is designed by this subject was systematically tested in the standard wind tunnel of Hebei Meteorological Bureau.The experimental results show that the maximum wind speed error is 0.08m/s when the system is less than 10m/s wind speed,and the maximum relative error is 1.65% in the range of 10~40m/s,which is much higher than the error requirement of the wind instrument.In the actual environment,compared with the VAISALA WXT-532 wind speed and direction instrument,the maximum instantaneous wind speed difference between the two devices is 0.28m/s,and the maximum instantaneous wind direction difference is 3.7°,which verifies the stability of the system under the actual environment.