Outdoor evaluation of sound source localization for drone groups using microphone arrays.

For robot and drone auditions, microphone arrays have been used for estimating sound source directions and sound source locations. By using sound source localization techniques, for example, drones can detect people calling for help even if the target person is not visible. Most sound source localization methods are based on estimated sound source directions and triangulation. However, when it comes to situations using drones, severe drone noise distorts direction estimation results which could worsen the localization results badly due to the discreteness of direction estimation. In this perspective, the authors have proposed a sound source localization method that can omit outlying triangulation points, which could improve its localization performance. In this paper, an outdoor experiment has been held, and the proposed method is evaluated whether it can localize a sound source even if real drone noise is added to the recordings. Experiment results show that the proposed method can localize with 4.15 m of estimation error for a sound source up to 50 m away, suppress the impact of outliers, and use only plausible triangulation points.