摘要
超声波流量计中存在各种噪声,直接影响流量测量的精度。文章首先分析了小管径超声波流量计中噪声的来源,从实时性的角度出发,提出了一种直接对测量时间差进行去噪的方法,避免了对原始超声波信号进行采样、分析带来的实时性差的问题。针对随机噪声和声学噪声引起的时间差数据中的误差,以硬阈值小波滤波作为第一级滤波、中值加均值滤波为第二级滤波进行处理。通过流量测量实验,验证了去噪方法的有效性,结果表明,去噪后流量计的瞬时测量误差小于1%。
The noise will directly affect the accuracy of the ultrasonic flow meter. The sources of noise inside the small pipe ultrasonic flow meter were analyzed. Considering the critical real-time measurement for the flow meter, a method of directly denoising the transit-time difference data was proposed. It avoided sampling and analyzing the original ultrasonic signal, which might lead to the poor performance of real-time measurement. For different noise sources, two different kinds of filters were applied. The wavelet filter was chosen as the first denoisng filter, which used a hard thresholding to reduce error from the random noise. A median filter and a mean filter were combined as the second denoisng filter to reduce error from the acoustic noise. The flow rate measurement experiment was implemented to verify the validity of the proposed denoising method. The results show that the instantaneous measurement error can be less than 1% after denoising.
出处
《中国空间科学技术》
EI
CSCD
北大核心
2015年第2期77-83,共7页
Chinese Space Science and Technology
关键词
超声波流量计
在轨加注
小波滤波
中值加均值滤波
航天器
Ultrasonic flow meter
In-orbit refueling
Wavelet filter
Median and mean filter
Spacecraft
