Improved DoA estimation with application to bearings-only acoustic source localization

This paper discusses an improved Direction of Arrival (DoA) estimation method for localizing acoustic events, applied to estimating the location of explosion of high explosive projectiles. The blast at sea of a projectile fired from a large caliber gun is recorded using a set of microphone arrays disposed in convenient locations at the shore line. The signals are enhanced and the directions of arrival estimated using an improved version of a state-of-the-art algorithm. The probable coordinates of the impact are then computed by means of a bearing-only target localization algorithm based on least squares. Aiming at improving accuracy, a nonlinear optimization constraint imposing unit norm in a data selective DoA estimation procedure is introduced. In addition, various preprocessing techniques are evaluated in order to determine the best option for this particular application. Results based on actual data from real world experiments are discussed thoroughly, including important practical details.