基于混合卷积窗六谱线插值的多普勒信号处理

Doppler signal processing based on mixed convolutional window six spectral lines

激光多普勒测速系统信号处理的过程中,通常采用快速傅里叶变换提取多普勒频移进而计算出被测物体运动速度,由于频谱泄露和栏栅效应的影响,会导致测量精度降低。本文提出了一种四项Nuttall窗和五项Rife-Vincent窗的混合卷积窗函数结合改进的六谱线插值算法来降低频谱泄露和栏栅效应所带来的影响,从而提高激光多普勒信号处理精度。搭建了双光束后向散射差动式激光多普勒测速平台,通过仿真和实测得出在加入了R_(SN)=-10 dB的高斯白噪声的情况下使用该混合卷积窗所测量的最小相对误差为0.0027%,而分别使用两个单一的窗函数测量的最小相对误差分别为0.0103%和0.0461%。从而验证了本方法的有效性。

In the process of signal processing in the laser Doppler velocity measurement system,the fast Fourier transform is usually used to extract the Doppler frequency shift and calculate the motion speed of the measured object.Due to the influence of spectrum leakage and barrier effect,the measurement accuracy can be reduced.In this paper,a hybrid convolution window function with a four-term Nuttall window and a five-term Rife Vincent window combined with an improved six spectral line interpolation algorithm is proposed to reduce the effects of spectrum leakage and barrier effects,so as to improve the accuracy of laser Doppler signal processing.A dual-beam backscattering differential laser Doppler velocimetry platform is built,and the minimum relative error measured with this hybrid convolution window with the addition of Gaussian white noise with R_(SN)=-10 dB is 0.0027%by simulation and real measurements,whereas the minimum relative errors measured using the two single window functions are 0.0103%and 0.0461%,respectively.Thus,the effectiveness of this method is verified.