Doppler angle estimation using the AR spectrum model

The transit time spectrum broadening effect has long been explored for Doppler angle estimation. Given acoustic beam geometry, the Doppler angle can be derived based on the mean Doppler frequency and the Doppler bandwidth. fast Fourier transform (FFT) based spectral estimators are typically used. One problem with this approach is that a long data acquisition time is required to achieve adequate spectral resolution. In this paper, an autoregressive (AR) model is proposed to obtain the Doppler spectrum using a limited number of flow samples. Since only a small number of samples are used, the data acquisition time is significantly reduced and real-time two-dimensional Doppler angle estimation becomes feasible. Results indicated that the AR method generally provided accurate Doppler bandwidth estimates. It also outperformed the conventional FFT method at small Doppler angles