Precision and accuracy of acoustic gunshot location in an urban environment
This provides a practical solution for forensic and public safety applications in urban areas, though it is incremental as it applies existing methods to real-world data.
The study evaluated the accuracy of acoustic multilateration for locating gunshots in an urban environment using the ShotSpotter system, finding that 96% of shots could be located within 15 meters when six or more sensors were used.
The muzzle blast caused by the discharge of a firearm generates a loud, impulsive sound that propagates away from the shooter in all directions. The location of the source can be computed from time-of-arrival measurements of the muzzle blast on multiple acoustic sensors at known locations, a technique known as multilateration. The multilateration problem is considerably simplified by assuming straight-line propagation in a homogeneous medium, a model for which there are multiple published solutions. Live-fire tests of the ShotSpotter gunshot location system in Pittsburgh, PA were analyzed off-line under several algorithms and geometric constraints to evaluate the accuracy of acoustic multilateration in a forensic context. Best results were obtained using the algorithm due to Mathias, Leonari and Galati under a two-dimensional geometric constraint. Multilateration on random subsets of the participating sensor array show that 96% of shots can be located to an accuracy of 15 m or better when six or more sensors participate in the solution.