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To the dot: gunshot location system pinpoints shots fired

In police work, there is no greater reward than saving lives.

If you could dispatch officers to a shooting scene within seconds, as opposed to minutes, and be able to direct the first responders to an exact location, how many lives could you save? How much more effective would responding officers be if they knew the exact spot the gunshots occurred, not just on the block, or the street address, but the exact physical location at that particular address, within feet?

The answer is: very effective. This article is about technology that can put responding officers at the exact location of where shots were fired and do it faster than a 9-1-1 call can. And in some cases, no 9-1-1 call is ever made so this technology becomes the only data available at all. This is actually how lives are being saved today. Let’s go inside the Richmond, CA, Police Department, which is located in the San Francisco East Bay area, with Sergeant Dave Harris to learn about how this gunshot location system is changing the speed and accuracy of his officers’ response to shots fired.

“On May 8, we had our first remarkable event using the ShotSpotter Inc., (Mountain View, CA) technology,” Harris said. That day the system alerted the department that shots had been fired. “Also, we received a 9-1-1 call. In the call, the citizen reported the block where the shots were heard. That was the extent of the description. ShotSpotter showed us not only the exact address, but what portion of the yard the shots came from at that address. A dot appeared on the computer screen.”

The department dispatched the police officers directly to the place in the yard the dot appeared and they found an AK47 in the side yard. “This was remarkable because it put our officers right exactly where the shooting happened,” Harris said. “We now call this ‘dispatching to the dot.’”

According to its Web site, the Richmond Police Department serves a diverse community of approximately 102,000 residents over a large geographic area that includes 32 miles of shoreline, numerous residential neighborhoods, an active port, significant industrial and technology resources, major retail and business centers, and several thousand acres of park land.

Harris, who has worked as a police officer for 28 years, in a department of 200 officers, says that Richmond public safety deployed the gunshot location system at the start of May 2009, to help locate shooting victims and get them help faster than before. They hoped it would be a good system, but according to Harris it turned out to be a great system.

“In urban areas there is a high number of gunshots and citizens get a little numb to the sound of shots fired so we didn’t always get the calls,” Harris said. “Sometimes we get no 9-1-1 call but ShotSpotter will get us to the location of a shot or shots fired. Dispatchers can listen to audio on the system and they will know if multiple shots were fired.”

The Richmond Police tested the response speed themselves by firing their own weapons and then timing the system. They found that ShotSpotter responded in 5 to 7 seconds. Comparatively, the 9-1-1 calls, by experience, would be measured in minutes after the shooting event from the average citizen. Harris noted that citizens often do not want to bother the 9-1-1 center with calls when they hear what may or may not be gunshots.

The next month, a police officer was on a traffic stop at an apartment complex known for gunfire incidents when the officer heard shots fired north of his location. The ShotSpotter hit showed the location to be even further north of the apartment complex on a side street and that’s where dispatch sent the officer. He found AK47 rounds and two people shot, one critical who had to be air-lifted out on a life-flight. “No 9-1-1 call was ever received,” Harris said. Both people survived.

“We never realized how many times we were not getting the calls,” Harris said. “It turned out to be about 50%. “We didn’t realize how good citizen cooperation was.” His officers found that because dispatch got them out to the incident so quickly, victims could be saved and also witnesses were still on the scene to interview.

Gregg Rowland, senior vice president at ShotSpotter explained: “We use ‘speed of sound’ to find gunshots or explosions. The system provides alerts on these events. A signal is sent to a server and it runs the sound against other sounds to determine a gunshot.”

Geo-location is employed by the system and GPS data is then plotted on a map. Sensors are positioned in an area and they all have GPS so the system knows the exact sensor and the real time. The system uses public safety’s GIS to work within the same view that dispatchers and supervisors are accustomed to seeing. “In five to seven seconds, the incident will show up at Dispatch or at the 9-1-1 Center of an agency,” Rowland said.

Sensors are positioned above the ground level 20 feet or higher, usually on the center section of buildings. Sensors are usually not positioned on light poles because they would be too visible there. They can come with or without radio, Ethernet, or connected through phone lines. Also, cellular radios can be used. This technology, known as the Gunshot Location System (which was recently renamed GLS-Stationary Array or GLS-SA).

According to Rowland, there goal is to put first responders right in the epicenter of the event. “Our evidence stands up in court, in murder trials, in life cases,” he said. “Our technology has been used in investigations with timing down to 100th of a second and within a few feet of shots fired.”

He mentioned they have mobile client software for the public safety officer who wants to feel safe and empowered in the field. He said the need for data and information is extremely high today and customers are moving to mobile solutions because things are so busy in the call queue.

Gunfire is high up in the queuing. “We have a product that allows officers in the patrol car to get instantaneous information that the dispatcher gets,” Rowland said. “Mobile clients get it a little differently. They receive the map and they can access more information by touchscreen. There is audio of the event too and they can play back and listen.”

Officers can make good judgements about what’s happening by using this technology. They can access a mutual aid channel to get more backup if needed. “About half of our existing clients are upgrading to this right now, and all new clients are taking the mobile system,” Rowland stated.

The company delivers training to the dispatchers, law enforcement personnel and command staff based on best practices. Also, they train prosecutors on how to use the data.

The technology is helping first responders get to the wounded before the 9-1-1 call. Use of the ShotSpotter GLS-SA has resulted in increased awareness and adoption among law enforcement agencies due to the life-saving benefits of their technology. According to the company, sales and deployments are occurring at a rising pace. In the recent quarter alone, the ShotSpotter GLS has been procured by the cities of Montgomery, AL; Trenton, NJ; as well as two Westchester County, NY cities: Mount Vernon and Yonkers.

“We are working with international clients right now and we have contracted with 45 agencies in the United States but that will probably rise to 65 or more by the end of 2009,” Rowland commented.

So what type of agency would it best fit? Rowland noted that it would fit any type of noise environment: from areas with all houses such as Palo Alto to noisy city environments like Boston and New Orleans. It works in cold climates as well.

First responder agencies, typically police and sometimes security, would be the most likely to use the system and EMS would need to be alerted quickly as well. “We have been able to help EMS by putting the console at EMS dispatch so they can arrive at the appropriate time with the appropriate level of assistance on hand,” Rowland said.

As of early this fall, the company announced that 57 gunshot victims have survived life-threatening wounds in 2009 thanks to the timely aid of first responders relying on accurate incident location data provided by their GLS technology.

Rowland also said agencies often purchase the technology for just one area because of the constraints of budget, but after they see the results, they expand the system to other areas.

Recently announced by the company at the International Association of Chiefs of Police (IACP) conference in Denver this fall were two new products: the ShotSpotter GLS-SO and the ShotSpotter GLS-MA, which the company says will “provide security and law enforcement customers solutions for short-term operations and for targeting shifting violent crime activity, respectively. In addition to real-time alerting of gunfire and explosive incidents, all incident information is permanently stored in a standard and open database that facilitates crime analysis and supports investigations and prosecutions with court-tested forensic evidence.”

The GLS-Special Operations (GLS-SO) is used for event-driven, temporary deployments, enhancing security at events and for dignitary visits. The second product, the GLS-Moveable Array (GLS-MA) adds mobility, giving law enforcement the ability to move the location of a portion or all of their coverage area to anticipate shifts in crime activity.

Public safety officers want and need the best technology available to deal with crime on the streets. It can be very hard to identify gunshot locations. A life may be in the balance. Seconds matter. “We are pleasantly surprised,” Harris said. “There is a significant benefit of having this technology. We can identify shooting victims. Our officers are impressed.”

Richmond Police get a detailed forensic report in the form of an affidavit. “Regarding court situations, a deputy DA once asked for a map of a shooting incident and the audio, which she then used in court to show just exactly how many shots were fired,” Harris said.

If an agency wants to stay on the leading edge of policing, this gunshot location system is the “tool to have,” according to Harris. “Getting the exact location of shots fired, right to the dot, that fast, is nothing short of remarkable.”

Tim Burke is a freelance writer and also an editor, designer and photographer who lives and works in Skokie, IL. He can be contacted at

Published in Public Safety IT, Nov/Dec 2009

Rating : 10.0

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