  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.
