一种提高超声波多普勒流量计测量精度的方法

摘要

由于强噪声背景下的多普勒超声波回波信号属于微弱信号，传统谱分析方法对微小多普勒偏移量的测量误差较大，使得现有的超声多普勒流量计在应用范围和测量精度上受到限制，因此提出采用Zoom FFT结合卡尔曼滤波来提高多普勒流量计的测量精度。文中首先采用Zoom FFT来提高多普勒回波信号的频率分辨率，然后通过卡尔曼滤波器递推跟踪频率偏移值，最后在Matlab环境下实现了Zoom FFT算法和卡尔曼滤波算法。现场测试结果表明：采用Zoom FFT结合卡尔曼滤波可以提高流量测量精度。%As the Doppler ultrasonic echo signal under strong noise background is belongs to the weak signal, the measure-ment error is large when the traditional spectrum analysis method was used to extract the doppler offset quality, so the usage of Doppler flow meter is limit in the application field and measurement accuracy for velocity doppler flow meter, A new method using Zoom FFT and kalman filter was adopted to improve the Doppler flow meter measurement accuracy.This paper used Zoom FFT to improve the frequency Doppler echo signal resolution, and then tracked the frequency offset value.The Zoom FFT algorithm and kalman algorithm under the Matlab environment were realized.The field test result shows that the flow measurement accuracy can be improved using Zoom FFT and kalman filter.