声学多普勒流速快速测量的设计

Design of rapid measurement of acoustic Doppler velocity

传统的多普勒流速剖面测量仪将混频正交与低通滤波在软件中实现,存在测量时间长、精度不高等问题。为解决上述问题,采用运算速度更快、内存容量更大的STM32H743单片机作为主控芯片,同时设计了将信号混频、正交与FIR低通滤波在硬件电路中实现的多普勒流速剖面仪,这样大大减少了CPU的运算时间,提高了测量精度。运用FFT算法进行信号质量分析,利用自相关算法计算出各层流速。通过试验,对测得的多普勒频偏以及流速进行分析,结果表明,系统的设计满足在实际小型河流中的精确测量,具有可行性。

In traditional Doppler velocity measurement,mixing quadrature and low-pass filtering are generally implemented in software,which results in relatively long measurement time and low accuracy.In order to solve the above-mentioned,STM32H743 single chip computer with faster operation speed and larger memory capacity has been used as the main control chip,and a Doppler velocity profiler is designed by using signal mixing,orthogonal and FIR low-pass filtering in the hardware circuit,which greatly reduces the CPU operation time and improves the measurement efficiency.At the same time,FFT algorithm has been used to analyze the signal quality,and autocorrelation algorithm has been used to calculate the velocity of each layer.Through the experiment,the frequency deviation and velocity are analyzed.The results show that the design of the system can meet the requirements of accurate measurement in actual small streams,and it is feasible.