明渠水声信号测速方法研究

Velocity measurement research of acoustic signal of open channel

发射波束与目标之间的相对运动会产生多普勒效应。根据多普勒频移可以测量目标的速度。利用此原理可以测明渠水流速。但由于噪声、主频的干扰,又由于离散频谱存在栅栏效应和假频现象,有些情况下回波的谱峰与真实的谱峰值相差很远,因此在搜索回波信号的多普勒频移时就无法对准其真实的频率,也就无法得到正确的流速。"叠加法"去随机干扰,"谱减法"去主频干扰,"全相位频谱校正"可避免信号离散化的影响。将三者综合运用,可以使测量到的谱峰值与真实值间基本一致。通过多组测试统计,证明该方法能够测得明渠水速,并且有较高的测量精度。

The relative move between transmitting beam and the target produced Doppler effect, which can be used to measure the velocity of open channel. However, because of noise interference, frequency interference, and barrier effect and false frequency, in some cases the echo＇ spectral peaks was far away from the true peak, so the result can not align their true frequency and the true water velocity. The comprehensive use of ＂superposition＂, ＂spectral subtraction＂ and ＂all-phase spectrum correction method＂ can make measurements to the true value of the spectral peak. Through multiple test statistics, it showes that the method can get open channel water velocity and higher accuracy.