Always Listening

Gunshot detection technology targets gun violence

• By Sherleen Mahoney
• Oct 05, 2009

A city has a soundtrack—vehicles honking, traffic rumbling, people shouting, emergency vehicle sirens screeching, car alarms blaring—and eventually, it all becomes white noise. Differentiating sounds, let alone their origination, can be difficult within this sea of noise.

Imagine hearing a sudden burst of what sounds like a gunshot. But was it a gunshot? Was it a car back firing, or maybe it was a firecracker? And from where did that sound come from? Without accurate information available, the sound registers but gets ignored.

With gunshot detection technology, police have a valuable surveillance tool in the fight against gun violence. This technology is cropping up in more and more cities around the United States.

Bring on the Big Guns

ShotSpotter is a leading provider of gunshot and explosion location and detection systems for law enforcement, homeland security and the military. The company made a name for itself when it assisted the FBI in capturing Ohio highway sniper Charles McCoy Jr. in 2004.

The shootings began in May 2003 along Interstate 270 in Columbus, Ohio, and residents were gripped with fear. The suspect continued to elude capture for months, and in late 2003, the FBI asked ShotSpotter to deploy its Gunshot Location System along the highway.

After three weeks of collecting forensic evidence, the system helped police establish the gunman’s M.O. and shooting pattern. This information led police to McCoy, who was arrested in March 2004. In the end, 24 sniper attacks were carried out and one person was killed. Soon after this success, other law enforcement agencies came knocking.

Deployment Strategy

For a typical city installation, the ShotSpotter GLS involves installing 16 to 20 sensors per square mile, placed 1,500 feet apart for triangulation purposes. They can detect events up to 1.5 miles away. The sensors, able to accurately and reliably differentiate between gunshots, fireworks and other explosions, are linked to cameras that are monitored by a central command center.

When a gunshot is detected, software triangulates the latitude and longitude of the shooting location, and within a second, the cameras automatically pan to that location and begin recording. The cameras zoom in on the location to capture details and zoom out to capture wide-angle pictures. Within five seconds, the central command center is notified of shots fired, the number of shots and the physical address of the incident area, along with the captured audio and video. That information is then transmitted to patrol cars, helicopters and wherever the municipality deems necessary. Responding officers are notified of the event and can arrive at the scene immediately. All information captured is court admissible.

Recent system enhancements include customizable analytic reports that reveal and highlight gunfire patterns and trends, further helping investigators, crime analysts and law enforcement agencies.

In October, the company will introduce the Moveable Array ShotSpotter GLS and the Special Events, VIP Protection and General-area Protection System. Both products give users the ability to monitor targeted areas for early detection of and response to attacks.

Tracking Trenton

Trenton, N.J., is the latest city to install the ShotSpotter GLS. Three-quarters of Trenton’s 7.6 square miles will be outfitted with detectors and cameras. The city expects the initial deployment to be live by the end of this year, and for the entire system to be up and running in a year and a half.

"We have been looking for some innovative technology to help us target gunfire, which has been affecting the quality of life in our communities," said Irv Bradley, director of the Trenton police department, in a press release. "We feel the ShotSpotter GLS is an extremely useful tool and will provide us with addition information about our city’s gunfire rates. This information will help us minimize gunfire in our crime hot spots and essentially improve the quality of life in our neighborhoods."

"In the fight against gun violence, law enforcement agencies across the United States are increasingly adding the ShotSpotter GLS to their arsenals, recognizing it as a mission-essential tool in their gun and violent crime reduction efforts," said Gregg Rowland, ShotSpotter’s senior vice president. "These cities will gain the benefit of having previously unattainable information about gun crime so they can proactively do something about it. This data puts valuable intelligence in the hands of public safety officials, allowing them to more effectively analyze and respond to gun crime trends. The end result will be increased safety for responding officers and the communities they serve."