Angle of arrival estimation based on warped delay-and-sum (WDAS) beamforming technique

In antisubmarine warfare (ASW), fast and accurate angle of arrival (AOA) estimation is required in order to localize fast motion targets such as torpedoes. For this purpose we introduce in this paper a new approach called warped delay-and-sum (WDAS) beamforming to estimate the AOA of a narrowband source with uniform linear array (ULA). The basic idea of warped delay-and-sum (WDAS) beamforming is based on calculating the spatial spectrum of the conventional delay-and-sum (DAS) beamforming at nonuniform spaced angles obtained by a spatial frequency transformation using a first order allpass function with a complex valued parameter. This research proves the perfection of the proposed method through simulation work. Moreover, a comparative study will be conducted to compare the performance with the conventional DAS beamforming.