SMALL, ROTOR POWERED, UNMANNED AERIAL VEHICLE DIRECTION OF ARRIVAL DETERMINATION USING BIO-INSPIRED MICROELECTROMECHANICAL SENSORS

Abstract

Previous research developed a bio-inspired microelectromechanical system (MEMS) acoustic sensor, based on the hearing organ of the parasitic fly Ormia ochracea. It was previously demonstrated that the direction of a small, rotor powered, unmanned aerial vehicle (UAV) can be estimated using this acoustic sensor. Building on this previous work, the objective of this study was to develop a method to unambiguously determine the direction of arrival of the sound of small UAVs using an array of collocated MEMS sensors. This task was performed under the premise that the directional response of the sensors in the array could be modified to exhibit an asymmetric dipole pattern or a cardioid pattern. The proposed DOA estimation method, using comparison across normalized calibration curves, was analyzed across several different conditions. Promising results were obtained, where the best accuracy was found for the array with a cardioid directional pattern. Error was as low as one degree across a 360° azimuth range for signal-to-noise ratios of 20 dB and higher for a small hexacopter UAV. The developed method can be applied to determine the direction of arrival of potentially any acoustic source detectable by the MEMS sensors.