Direction of Arrival Estimation Using a Small Circular Array

Direction of arrival (DOA) is estimated for a small circular array with six elements and a radius of 0.0875 m using superdirective beamforming. It is well known that such an array has a wide beam width using conventional beamforming (CBF). CBF yields high sidelobe levels which cause the signal from one direction to leak into another direction. A superdirective beamforming method based on deconvolution (T. C. Yang, IEEE J. Oceanic Eng., 44, 156-166, 2019) has been shown to yield high bearing resolution, high directivity index or array gain, and strong interference rejection compared with CBF for an array of 16 elements, for which the beam pattern is shift-invariant. For a circular array of 6 element, the beam pattern is shift variant, a modified Richardson-Lucy deconvolution method is used.This paper presents the simulation results, and experimental test results in a tank. A small circular array can be used in principle to estimate the positions of neighboring node, and differentiate signals from different sources to avoid signal collisions in an underwater communication network.