ULA Delay-and-Sum Beamforming for Plume Source Localization

Estimating the direction of a diffusive source is a difficult problem, and little has been tried to estimate a chemical source subject to turbulence. Turbulence lence must be addressed if chemical localizer systems are to be effective for real-world implementation. Previously, we show that a cross-correlation method is a simple and effective way to determine the direction-of-arrival of a single chemical source subject to turbulence. Now, we examine the performance of a uniform linear array (ULA) delay-and-sum beamformer to find and track the direction-of-arrival of a chemical. Due to the time-varying gain from the beamformer, we are better able to examine the modulated (von Karman vortex street) plume. We show that the delay-and-sum beamformer has the best results if it is parallel to the direction of propagation and that localization begins to degrade when the array is at a wide angle to the plume, due to non-rectilinear flows and dissipation outside the streamline. Yet, we show that a ULA beamformer gives dynamic information about the plume that can be used for direction-of-arrival (DOA) tracking, in addition to estimation.