Passive three-dimensional precision method for locating vocalizing animals and other sound sources

In biology and environmental science, it is often necessary to locate animals that cannot be monitored using traditional methods. We present a method capable of locating sound sources, such as vocalizing animals, without interfering with them or their habitat. A new approach for 3D acoustic multilateration, based on the time of arrival of sound at four microphones arranged in a trihedral geometry, is presented. Four synchronized, low-cost microcontroller systems are coupled to these microphones. The sound arrival times were recorded and processed by the proposed algorithm to determine the spatial locations of the sources. Practical results demonstrated a maximum average relative error of 3.03% and a mean average relative error of 1.97%. The total system cost was approximately six hundred dollars. This paper introduces a passive method for precisely locating sound-emitting objects within decameter-sized fields, achieving centimeter-level accuracy. The method’s foundation relies on straightforward mathematical principles, and its cost is thoroughly discussed. In addition to locating sound sources and vocalizing animals, this method can be used for tracking and counting individuals.