Gunshot localization system improves emergency services response to active shooter events
HSNW: What is the maximal distance at which a Databuoy sensor can identify and locate a gun shot? If the sensor requires a bullet to travel at supersonic speed in order to be located (by “listening” to the supersonic shock waves created at that speed), what happens when a bullet slows down?
Griggs:The detection range for a gunshot depends on the type of weapon and the direction of fire. To capture the weakest signals, such as from a .22 caliber pistol shooting away from the network, sensors may need to be spaced on the order of 100m or less.
In terms of tracking the bullet, we rely on the presence of a supersonic shockwave signal to formulate a trajectory. If the bullet is not supersonic, a trajectory will not be computed. If, in the case you mentioned, the bullet “slows down,” then it is no longer supersonic and no shockwave is emanating. However, it is more than likely that there will at least be a number of shockwave detections from the time the bullet is supersonic, and a trajectory will be computed from those (bullets tend to travel in straight lines, so a small number of detections can formulate a valid solution).
HSNW: Electro-optical detection systems appear to have several advantages relative to acoustic location systems: Optical systems can process the incoming shot signatures more quickly than acoustic systems can. They can also identify categories, characteristics, and sometimes specific weapon types automatically. What are the advantages of acoustic systems relative to optical systems?
Griggs:Optical systems detect and classify gunshot signatures but are vulnerable to solar and man-made clutter and have other disadvantages in terms of localization capabilities and cost. We believe the best solution for area coverage, is one that can detect and localize in both indoor and outdoor environments with predictable consistency in a product that can be widely available. In a commercial security application, the technology needs to be affordable and robust. We think the acoustic approach offers that.
HSNW: What is the level of confidence now attached to acoustic gun-shot location systems? It is one thing to have police dispatchers send officers quickly to the scene of 6 shooting – and another thing to use such evidence to convict a suspect in court. Has acoustic system-based evidence been used in courts to convict shooters?
Griggs:Our system has been shown to detect all shots in testing while operating for months with no false alarms. We would not expect our shot alerts to be used as evidence in a court proceeding. We do not transmit the full acoustic signature. We have integrated our shot alerts with area video surveillance cameras that can capture an image and video clip of the shooter at the moment of the shot and can provide instant, clear information about the event.
HSNW: What is the cost of deploying a ShotPoint system in a typical urban setting? A ShotSpotter system costs about upward of $300,000 per square mile covered, with maintenance, upgrades, and retaining fees adding more than $50,000 a year to the initial cost. For strapped-for-cash policed departments, this is a hefty price-tag.
Griggs:We are not marketing directly to police departments. Our sales model is to provide our hardware as a component to a turnkey solution offered by smart lighting manufacturers or physical security integrators in the commercial sector.
HSNW: What cities have so far adopted the Databuoy system? Have these cities reported a reduction in crime violence, and increase in arrests related to gun violence, and an increase in convictions based on acoustic evidence?
Griggs:We prefer not to comment on who our customers are at this point.
HSNW: Have foreign police departments shown interest in the company’s system? In some countries – Honduras, El Salvador, Guatemala, South Africa – the rate of urban violence is higher than that in the U.S., although governments are typically much poorer.
Griggs:We have had some inquiries about our system from outside the U.S., but no sales to date. Our system is exportable.
HSNW: If Databouy technology was available on 22 November 1963, and the company’s sensors were deployed at Dealey Plaza in Dallas, Texas – would we know, with absolute certainty, whether Lee Harvey Oswald was the lone shooter, or whether there was another shooter on the Grassy Knoll? Can the technology be used now, in a scientific re-enactments of the shooting, to provide a definitive answer to that question?
Griggs:I can’t comment on the possibility of a scientific reenactment since our system relies on our particular 4-channel array sensor design and a certain collection speed. We could locate the shooter with absolute certainty.
See an example of an outdoor shot report [see image on previous page]: the red line is the trajectory of the bullet and the blue dot is the shooter. Our system eliminates multipath so the Dallas case would not have posed any difficulties.