Acoustic location of gunshots using combined angle of arrival and time of arrival measurements

Abstract

A gunshot location system computes candidate gunshot locations from angle-of-arrival information and time-of-arrival information provided by acoustic sensors. In addition to an angle, each sensor calculates an angular uncertainty from impulses received at four or more microphones having rotational symmetry. An intersection of one or more time-of-arrival hyperbolas with one or more angle-of-arrival beams is used to determine a candidate gunshot location. In simple environments, a location can be confirmed with just two sensors allowing sensor density to be significantly reduced, while in complex environments including reflections, blocking, and interfering acoustic events, the additional angle-of-arrival information improves location accuracy and confidence, allowing elimination of candidate locations inconsistent with the combined time-of-arrival and angle-of-arrival information.

1 . A gunshot location system comprising a collection of acoustic sensors, a computer for computing gunshot locations using information communicated from the acoustic sensors, and communication links connecting the acoustic sensors to the computer,
 wherein the collection of acoustic sensors comprises a first acoustic sensor and a second acoustic sensor,   wherein the first acoustic sensor communicates to the computer time-of-arrival information derived from acoustic impulses sensed at the first acoustic sensor and angle-of-arrival information derived from the acoustic impulses sensed at the first acoustic sensor,   wherein the second acoustic sensor communicates to the computer time-of-arrival information derived from acoustic impulses sensed at the second acoustic sensor; and   wherein the computer for computing gunshot locations computes a hyperbola from the time-of-arrival information communicated from the first and second acoustic sensors.   
     
     
         2 - 64 . (canceled)