Isomorphism between pulsed-wave Doppler ultrasound and direction-of-arrival estimation .1. Basic principles

Direction-of-arrival (DOA) estimation of signals is an important area of research in sonar and radar signal processing, Over the last few decades, numerous techniques have been developed for high-resolution DOA estimation. In this paper, we show that velocity measurement using pulsed-wave Doppler ultrasound and DOA estimation are isomorphic problems, We discuss a number of DOA methods and their potential application to flow velocity measurement using ultrasound, Wide-band DOA methods are of special interest because the pulses used for Doppler ultrasound are also wide band. These wide-band methods generally involve a preprocessing step to convert wideband signals to narrow band before applying high-resolution techniques, Application of DOA methods to Doppler ultrasound provides tools for high-resolution velocity measurement, identification of multiple velocity components within a sample volume, and clutter rejection.