DOA estimation using spatial smoothing with overlapped effective array aperture

Spatial smoothing (SS) has widely been used for direction-of-arrival (DOA) estimation using an array antenna in case of multiple coherent waves incident or only a small number of snapshots available. After this preprocessing, the effective array aperture is reduced. It is possible to overcome the drawback of SS by using the augmented array aperture technique called SSIA (spatial smoothing with improved effective aperture). SSIA is a technique that makes effective use of the shift invariance of the array steering matrix and can be applied to DOA estimation algorithms such as ESPRIT. However, if multiple snapshots are utilized, SSIA cannot work well because the array steering matrix changes depending on snapshots. Therefore, this paper proposes a new technique of using the augmented array aperture in a similar manner, which is called SSOA (spatial smoothing with overlapped effective aperture). Computer simulation results show that the proposed technique provides successful DOA estimation of multiple coherent sources for the case of more than one snapshot.