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require more than one microphone to locate gunshots, most electro-optical systems require more than one sensor when covering 360 degrees. Acoustic and optical sensors can be co-located and their data can be fused thereby enabling the gunshot location processing to have a more exact discharge time that can be used to calculate the distance of the discharge to the sensors with the greatest possible precision. Optical systems are (essentially) not limited to the number of individual shots being fired or the number of different shooters shooting simultaneously, allowing optical-based sensing to easily declare and locate shooters conducting ambushes that employ multiple shooters, shooting from multiple locations during the same time period.
571:" (the practice of shooting weapons in the air for fun). Gunshot location systems based upon wide-area acoustic surveillance coupled with persistent incident data storage transcends dispatch-only uses because reporting of urban gunfire (via calls to 9-1-1) can be as low as 25%, which means that law enforcement agencies and their crime analysts have incomplete data regarding true activity levels and patterns. With a wide-area acoustic-surveillance-based approach combined with a persistent repository of gunfire activity (i.e., a database), agencies have closer to 100% activity data that can be analyzed for patterns and trends to drive directed patrols and
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575:. Additional benefits include aiding investigators to find more forensic evidence to solve crimes and provide to prosecutors to strengthen court cases resulting in a higher conviction rate. With the accuracy of a gunshot location system and the ability to geo-reference to a specific street address, versus a dearth of information that typically is the case when citizens report gunfire incidents to 9-1-1, agencies can also infer shooters by comparing with known criminal locations, including those on parole and probation; investigators can also at times infer intended victims and hence predict and prevent reprisals.
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enough away will not be detected because the amount of gunshot signal (both acoustic and
Infrared) eventually fades into the background signals. For acoustic systems that require the supersonic shock wave for location determination, the bullet must still be traveling at supersonic speed when it passes the sensor, and it must pass the sensor within the lateral span of the shock wave. For infrared sensing of the flash upon a weapon's discharge, the bullet path is not determined. Combining these two approaches improves the capability under various conditions anticipated in a combat scenario.
223:, approached the Menlo Park police department to ask if they would be interested in applying seismological techniques to locate gunshots. Others had also approached the Menlo Park police department suggesting ways to help the police by means of gunshot location systems. The police chief arranged a meeting with local inventors and entrepreneurs who had expressed an interest in the problem. At that time there were no solutions to tracking gunshots, only a desire to do so. One key attendee was Robert Showen, a
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conveying audio clips of the discharges with the alert information that provides additional invaluable information regarding the situation and its severity. Similarly for the protection of critical infrastructure, where the information is clearly and unambiguously conveyed in real-time to regional crisis command and control centers, enabling security personnel to cut through often inaccurate and delayed reports so they may react immediately to thwart attacks and minimize subsequent activity.
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the sequence of all-or-none (spike) events, or temporal patterns, transmitted between artificial "neurons". Identifying the nonlinear input/output properties of neurons involved in forming memories for new patterns and developing mathematical models of those nonlinear properties enable the identification of specific types of sounds. These neural networks can then be trained as "recognizers" of a target sound, like a gunshot, even in the presence of high noise.
234:. A network consisting of one wired and four radio-telemetered microphones was established, with his home in eastern Menlo Park becoming the command center. Lahr modified the software typically used for locating earthquakes and recorded the data at a higher sample rate than is used for regional seismology. After gunshots were heard, Lahr would determine their location while his wife monitored the police radio for independent confirmation of their source.
193:, working with Délégation Générale pour l’Armement (DGA) – the French defence procurement agency – studied the acoustic signature of submarines. The DGA & Section Technique de l’Armée de Terre (STAT), the French Army’s engineering section subsequently commissioned Metravib D. to find a solution for shot detection, a way to assist soldiers and peacekeepers who come under fire from snipers without knowing precisely where the shots were coming from.
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sensors and to discern the number of rounds fired, often an indicator of incident severity, are both tolerable and a drastic improvement for typical police dispatching scenarios when compared against the several minutes that elapse from when an actual discharge occurs to the cumulative time of several minutes that pass when a person decides to place a 9-1-1 call and that information is captured, processed, and dispatched to patrol officers.
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detection and alerting to a nearby shooter in the vicinity of the system; such uses are typically used to help protect soldiers, military vehicles and craft, and also to protect small open-space areas (e.g., parking lot, park). The latter are used for protecting large areas such as cities, municipalities, critical infrastructure, transportation hubs, and military operating bases.
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sounds of gunfire at minute differences in time, allowing the system to calculate the range and bearing of the origin of the gunfire relative to the system. Military systems generally rely on both the muzzle blast and projectile shockwave "snap" sounds to validate their classification of gunfire and to calculate the range to the origin.
212:, were besieged with crime. During 1992 there were 42 homicides in East Palo Alto, which resulted in East Palo Alto becoming the murder capital of the United States. The Menlo Park police department was often called upon to investigate when residents reported gunshots; however there was no way to determine their source from scattered
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may propagate as much as 2 miles. Therefore, a co-located array of microphones or a distributed array of acoustic sensors that hear a muzzle blast at different times can contribute to calculating the location of the origin of the discharge provided that each microphone/sensor can specify to within a millisecond
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Infrared-based detection systems can detect not only ordnance blast signatures but also large caliber weapons such as mortars, artillery, Rocket-Propelled munitions, machine guns as well as small arms. These systems can also detect bomb impact explosions, thereby locating the impacts of indirect fire
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The combination of both approaches (acoustic and infrared) assists in overcoming each system's own limitations while improving the overall capability to eliminate false declarations of gunshots and/or ambiguous declaration locations. Even when these combined systems are employed, shots fired from far
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Acoustic-only based systems typically generate their alerts a few seconds slower than optical sensing systems because they rely on the propagation of sound waves. Therefore, the sound reaching a sensor 1 mile from its origin will take almost 5 seconds. A few seconds to accommodate pickup from distant
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are designed to minimize the visible signature of the gunfire. Flash suppressors break up the expanding gases into focused cones, thereby minimizing the blossoming effect of the exploding gasses. These focused cones contain more of the signature in a smaller volume. The added signal strength helps to
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In addition to using gunshot location systems to convey incident alerts, they also can relay their alert data to video surveillance systems in real-time, enabling them to automatically slew cameras to the scene of an incident. Real-time incident location data makes the video surveillance smart; once
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Using common data-networking methods, alerts of the discharges can be conveyed to dispatch centers, commanders, and field-based personnel, allowing them to make an immediate assessment of severity and initiate appropriate and decisive force response. Some systems have the capability of capturing and
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revise their records based upon information they receive from police agencies, so that a sound originally classified by the automated system as the beat of helicopter rotors has been reported first as three, then four, and finally as the sound of five separate gunshots. As a result, this technology
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Optical and electro-optical systems have seen success in military environments where immediacy of response is critical and because they generally do not need careful location registration as is generally the case for more permanently installed "civil" crime fighting systems. Just as acoustic systems
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directly correlates to urban activity (e.g., automobile traffic, airplane traffic, construction, and so on). During the day, when the noise floor is higher, a typical handgun muzzle blast may propagate as much as a mile. During the night, when the noise floor is lower, a typical handgun muzzle blast
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Optical flashes can be detected using optical and/or infrared sensing techniques; however there must be a line of sight from the sensor to the weapon, otherwise the flash will not be seen. Indirect flashes that bounce off nearby structures such as walls, trees, and rocks assist in exposing concealed
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reported in 2008 that it had helped locate 62 victims of violent crime and aided in 9 arrests. In addition to assaults, the system detected a large amount of "random" gunfire, all totaling 50 gunshots a week in 2007. Based on the system's success, the police department decided to expand the program
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Gunshot location systems have been used domestically in urban areas since the mid-1990s by a growing list of cities and municipalities that are embracing gunshot location systems as a mission-essential tool in their arsenal for fighting violent crime. Federal and homeland security agencies too have
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Electro-optical detection systems currently tested (2011) can process the incoming shot signatures at very fast speeds, providing an excellent method not only to discriminate between weapon firings and other non-gunshot events but also to identify categories, characteristics, and sometimes specific
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are more commonly used in battle scenarios where it is important for potential targets to be immediately alerted to the position of enemy fire. A system that can hear minute differences in the arrival time of the muzzle blast and also hear a projectile's shockwave "snap" can calculate the origin of
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The projectile generally must travel within 50 to 100 meters of a sensor in order for the sensor to hear the shockwave. The combination of a muzzle blast and a shockwave provides additional information that can be used along with the physics of acoustics and sound propagation to determine the range
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that are trained and then listen for a sound signature in acoustic events. Like other acoustic sensing systems, they are fundamentally based on the physics of acoustics, but they analyze the physical acoustic data using a neural network. Information in the network is coded in terms of variation in
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to the area where the weapon is being fired or the projectile while it is in motion. Although a general line of sight to the shot event is required, detections are sometimes available as the infrared flash event bounces off surrounding structures. Just like acoustic-based systems, electro-optical
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Using this system, Lahr was able to demonstrate to the police and others that this technique was highly effective, as the system was able to locate gunshots occurring within the array to within a few tens of meters. Although additional techniques from the seismic world were known that could better
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Distributed sensor arrays have a distinct advantage over stand-alone systems in that they can successfully classify gunfire with and without hearing a projectile "snap" sound, even amid heavy background noise and echoes. Such systems are the accepted norm for urban public safety as they allow law
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Different system architectures have different capabilities and are used for specific applications. In general there are 2 architectures: stand-alone systems with local microphone arrays, and distributed sensor arrays ("wide-area acoustic surveillance"). The former are generally used for immediate
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had previously consisted of methods, among them spatial, spectral, and creative temporal filters, to eliminate solar glint as a false alarm. Earlier sensors could not operate at speeds fast enough to allow for the incorporation of matched temporal filters that now eliminate solar glint as a false
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Most stand-alone systems have been designed for military use where the goal is immediately alerting human targets so they may take evasive and/or neutralization action. Such systems generally consist of a small array of microphones separated by a precise small distance. Each microphone hears the
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light have successfully been used as sensing technologies. Both applications can be implemented to detect gunfire under static and dynamic conditions. Most police-related systems can be permanently mounted, mapped and correlated as the sensors remain in place for long periods. Military and SWAT
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In public safety and law enforcement, gunshot location systems are often used in high-crime areas for rapid alerts and awareness into the communications and dispatch center where the alerts are used to direct first responders to the scene of the gunfire, thus increasing arrest rates, improving
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enforcement agencies to hear gunfire discharges across a broad urban landscape of many square miles. In addition to urban cityscapes, the distributed-array approach is intended for area protection applications, such as critical infrastructure, transportation hubs, and campuses.
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In general categories, there are environmental packaged systems for primarily outdoor use (both military and civilian/urban) which are high cost and then also lower cost consumer/industrial packaged systems for primarily indoor use. Systems used in urban settings integrate a
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where it was first used operationally. Early sound-based systems were used primarily for large weapons. Weapons detection and location systems and counter-sniper systems have been deployed by the US Department of
Defense as well as by the militaries of other countries.
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passing overhead. Analysis of the spectral content of the sound, its envelope, and other heuristics are also commonly used methods to classify whether loud, sudden sounds are gunfire. Identifying the source of the sounds can be subjective, and companies such as
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have a similar advantage at night because the sensor does not have to contend with any solar contributions to the background signal. At night, the signature of the gunshot will not be partially hidden within the background of solar infrared contributions. Most
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it detected the impulse. Using this information, it is possible to discriminate between gunfire and normal community noises by placing acoustic sensors at wide distances so that only extremely loud sounds (i.e., gunfire) can reach several sensors.
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or limited line-of-sight detections between the weapon and the sensor. Because only optical flashes are detected, such systems are typically capable of determining only the bearing of a discharge relative to sensor unless multiple systems
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Gunshot location systems are used by public safety agencies as well as military/defense agencies. They have been used primarily in dispatch centers for rapid reaction to gunfire incidents. In military/defense, they are variously known as
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cameras have slewed to the scene, the information can be viewed to assess the situation and further plan necessary response; the combined audio and video information can be tagged and stored for subsequent use as forensic evidence.
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DefenseReview.com (DR): An online tactical technology and military defense technology magazine with particular focus on the latest and greatest tactical firearms news (tactical gun news), tactical gear news and tactical shooting
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so the display includes a map and address location of each incident. Some indoor gunfire detection systems utilize detailed floor plans with detector location overlay to show shooter locations on an app or web based interface.
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Regardless of the methods used to isolate gunfire from other impulsive sounds or infrared sensing, standard triangulation methods can be used to locate the source of the gunshot once it has been recognized as a gunshot.
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that uses open source hardware, cloud technology, machine learning, and 3D printing to build inexpensive gunshot detectors capable of locating and classifying gunfire in urban, public, and school spaces within seconds.
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Gunshot location systems generally require one or more sensing modalities to detect either the fact that a weapon has been fired or to detect the projectile fired by the weapon. To date, sound, vibration and visual or
345:(also known as "silencers"), the efficacy of gunshot detection systems may be reduced for suppressed weapons. The FBI estimates that 1% or fewer of crimes that involve gunfire are committed with suppressed guns.
135:, security, military, government offices, schools and businesses to identify the source and, in some cases, the direction of gunfire and/or the type of weapon fired. Most systems possess three main components:
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420:", because capturing conversations is only an inadvertent capability of the system's design, and law enforcement agencies have stated that the recording happens only after shots have been detected.)
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Due to their ability to sense at great distances, to sense in a non line-of-sight manner, and the relatively low bandwidth required for transmitting sensor telemetry data, systems deployed for
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In the 15 months it's been in operation, officers have made only four arrests and confiscated seven weapons that can be attributed to ShotSpotter technology, Police Chief
William McManus said.
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Both optical and acoustic sensors have been used from vehicles while on the move in urban and rural environments. These sensors have been tested on airborne and waterborne platforms as well.
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that occurs as a projectile moves through the air at supersonic speed. Note, this does not apply to subsonic ammunition, whose bullet projectiles do not exceed 1120 feet per second (i.e. the
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the discharge. Multiple gunshots, fired from multiple locations at nearly the same time, such as those found in an ambush, can provide ambiguous signals resulting in location ambiguities.
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Lahr decided to go ahead with his plans to demonstrate the feasibility of locating the gunshots, relying on his background in the earthquake location techniques and monitoring in
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550:, or other similar terms. Uses include alerting potential human targets to take evasive action, to direct force response to neutralize threats, including automated weapon cuing.
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the shot range. Multiple gunshots, fired from multiple locations at nearly the same time, are easily discriminated as separate gunshots because the sensors generally utilize a
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discontinued its $ 500,000 ShotSpotter service, after finding it had only resulted in four arrests and seven weapons confiscated in the 15 months it has been in operation.
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PILAR V Acoustic
Gunshot detector essential sensor of the vehicle protection system for an advanced situational awareness and for a greater force protection.
700:; Integration with cameras that point in the direction of gunfire when detected is also implemented. As of 2014, utility sites in the USA use 110 systems.
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officer safety, securing witnesses and evidence, and enhancing investigations, as well as in the long run deterring gun crimes, shootings and especially "
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actions, on the other hand, operate in more dynamic environments requiring a fast setup time or a capability to operate while the sensors are on move.
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embraced gunshot location systems and their benefits; notably the FBI successfully used a ShotSpotter gunshot location system during the 2003–2004
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There are three primary attributes that characterize gunfire and hence enable the detection and location of gunfire and similar weapon discharges:
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A typical muzzle blast generates an impulse sound wave with a sound pressure level (SPL) that ranges from 120 dB to 160 dB
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Many techniques can be used to discriminate gunfire (also referred to as "classifying gunfire") from similar noises such as cars
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weapons like artillery and mortars. The detector can be used as an automated shot correction sensor for close arms support.
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Because such systems have arrays of highly sensitive microphones that are continuously active, there have been concerns over
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automate the system and increase its reliability, those improvements were outside the scope of this feasibility study.
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Another method of classifying gunfire uses "temporal pattern recognition," as referred by its developer, that employs
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systems can generally be degraded by specialized suppression devices that minimize their sound or optical signatures.
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systems detect either the physical phenomenon of the muzzle flash of a bullet being fired or the heat caused by the
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with this broad ability to record conversations without the knowledge of those being recorded (this is "collateral
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Location of
Acoustic Sources Using Seismological Techniques and Software, USGS Open-File Report 93-221
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that occurs when an explosive charge is ignited to propel a projectile from the chamber of the weapon
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386:(the sound either of the projectile or bullet as it passes through the air), the sound of the
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Gunfire acoustics must be distinguished reliably from noises that can sound similar, such as
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Acoustic threat-detection systems include the
Unattended Transient Acoustic MASINT Sensor (
493:. It is meant to be an investigative tool rather than a source of primary legal evidence.
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or other weapon fire using acoustic, vibration, optical, or potentially other types of
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of a discharge to the sensor, especially if the round or type of projectile is known.
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939:"Is shot spotter reliable enough? Critics question human equation behind technology"
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911:"Man once accused of attempting to kill a Rochester cop now cleared of all charges"
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613:, has been successfully relied upon to locate gunfire in the area of coverage. The
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As of 2016, detection systems were deployed to a number of cities, including
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System that detects and conveys the location of gunfire or other weapon fire
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1111:"Secret Service conducts live test of ShotSpotter system at White House"
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Raytheon's gunshot detection system being deployed by utility companies
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in the United States have primarily been based on acoustic techniques.
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1033:"Surveillance Technology Helps Boston Police Find Location Of Gunfire"
874:(KBCW CW San Francisco news report, posted to YouTube on May 23, 2014)
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of the weapon when it fires the projectile, or a combination of both.
131:, as well as a combination of such sensors. These systems are used by
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Determination of the origin of gunfire by sound was conceived before
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began testing the use of gunshot detection technology to protect the
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590:, in April 1996. Through 2007, the manufacturer touted the device as
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Determination of the origin of gunfire by sound was conceived before
1262:"South Africa tries gunfire location system to catch rhino poachers"
1187:"Anti-Sniper/Sniper Detection/Gunfire Detection Systems at a Glance"
1067:"New York Police Begin Using ShotSpotter System to Detect Gunshots"
964:"New York Police Begin Using ShotSpotter System to Detect Gunshots"
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1238:"High-Tech Gunfire Locator May Nab Rhino Poachers in South Africa"
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of the bullet as it moves through the air. Such systems require a
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886:"A Black man risks all to clear his name - and expose the police"
796:, has adapted ShotSpotter technology with hydrophones to combat
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The technology was tested in
Redwood Village, a neighborhood of
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In 1990, a unique algorithm was used as a starting point :
103:, a gunfire locator, being used by British forces in Afghanistan
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Because both the optical flash and muzzle blast are muffled by
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consisting of many sensitive pixels. Each pixel in the entire
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765:, gunfire locators are being used to prevent rhino poaching.
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In late 1992, John C. Lahr, a PhD seismologist at the nearby
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is higher during the daytime and lower at night, where the
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Urban areas typically exhibit diurnal noise patterns where
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Earthquake
Technology Fights Crime, USGS Fact Sheet-096-96
1014:"Gunshot Detection System Will Soon Cover All Of Hartford"
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showed it was most effective as a "perception" of action.
1132:"San Antonio police cut pricey gunshot detection system"
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as to its effectiveness. It is effective in reducing
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is a system that detects and conveys the location of
151:, etc) either co-located or geographically dispersed
64:, and by adding encyclopedic content written from a
583:, in conjunction with the Franklin County Sheriff.
1315:"Incredible tech detects gunfire across America"
285:(e.g. 640×480 pixels) is constantly evaluated.
1050:"Police chief details gunfire location system"
157:A user-interface that displays gunfire alerts
8:
1293:"Creating a ‘Fire Alarm’ for Terror Attacks"
1213:History of the U.S. Army Research Laboratory
872:Gunfire locator used to record conversations
792:, a project under the fiscal sponsorship of
1216:. Government Printing Office. p. 73.
382:Acoustic systems "listen" for either the
84:Learn how and when to remove this message
1288:"From acoustic detection to data fusion"
1092:, 17 June 2014. Accessed: 19 June 2014.
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618:to cover nearly a quarter of the city.
179:where it was first used operationally (
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548:weapons detection and location systems
45:contains content that is written like
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1159:"GPA 30 17 Gunshot Detection System"
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485:has been rejected in court cases as
1130:Davila, Vianna (August 17, 2017) .
855:"Physicist Pinpoints Urban Gunfire"
1109:Farivar, Cyrus (August 26, 2017).
853:Kornei, Katherine (14 June 2018).
821:– gunfire locator by BBN and DARPA
609:A ShotSpotter system installed in
227:employee and expert in acoustics.
25:
990:"District Adding Gunfire Sensors"
204:In the early 1990s, the areas of
1313:Barrie, Allison (2 March 2017).
1274:from the original on 2022-09-01.
1018:Hartford Courant, March 28, 2016
937:Craig, Gary (17 November 2017).
615:Washington, DC Police Department
34:
884:Levinson, Reade; Girion, Lisa.
717:United States Naval Observatory
221:United States Geological Survey
749:, which were developed by the
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988:Klein, Allison (2008-07-05).
774:Soter gunshot locator project
164:geographic information system
1155:United States Secret Service
709:United States Secret Service
602:. Surveys conducted for the
459:weapon types automatically.
374:Acoustic source localization
909:Craig, Gary (31 May 2018).
581:Ohio highway sniper attacks
225:Stanford Research Institute
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1089:United Press International
819:Boomerang (countermeasure)
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694:Wilmington, North Carolina
686:Springfield, Massachusetts
670:New Bedford, Massachusetts
596:local officials were split
498:artificial neural networks
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334:increase detection range.
326:Infrared detection systems
573:intelligence-led policing
111:Shooting Detector Diagram
1137:San Antonio Express-News
751:Army Research Laboratory
745:), Serenity Payload and
642:Cambridge, Massachusetts
343:muzzle blast suppressors
121:gunshot detection system
1341:Weapons countermeasures
729:Artillery sound ranging
242:Gunfire characteristics
183:Artillery sound ranging
1351:Counter-sniper tactics
1065:Schlossberg, Tatiana,
962:Schlossberg, Tatiana.
943:Democrat and Chronicle
915:Democrat and Chronicle
825:Counter-sniper tactics
794:Earth Island Institute
769:Open Gunshot Detectors
544:counter-sniper systems
509:Optical discriminating
463:Discriminating gunfire
210:Menlo Park, California
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112:
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790:Stop Fish Bombing USA
372:Further information:
266:speed of sound in air
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110:
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66:neutral point of view
1299:, November 23, 2015.
1056:, February 21, 2012.
1039:, December 23, 2011.
763:Kruger National Park
723:Military and defense
707:In August 2017, the
475:, or the sound of a
384:bullet bow shockwave
301:explosions and cars
1356:Security technology
1242:Scientific American
1157:(August 25, 2017).
1082:Tomkins, Richard. "
1054:starnewsonline..com
994:The Washington Post
630:Birmingham, Alabama
623:Baltimore, Maryland
569:celebratory gunfire
512:alarm contributor.
489:for the purpose of
58:promotional content
830:Counter-insurgency
800:on coral reefs in
761:In South Africa's
702:San Antonio, Texas
626:Bellwood, Illinois
202:
149:infrared detectors
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105:
60:and inappropriate
1223:978-0-16-094231-0
1073:, March 16, 2015.
996:. Washington Post
757:Wildlife poaching
403:homeland security
378:Acoustic location
339:flash suppressors
331:flash suppressors
279:focal plane array
154:A processing unit
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16:(Redirected from
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778:community effort
690:Washington, D.C.
588:Redwood City, CA
310:background noise
191:Metravib defence
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47:an advertisement
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18:Gunshot location
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1366:Gun politics
1361:Gun violence
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859:www.aps.org
814:Gun control
735:World War I
713:White House
666:Minneapolis
658:Los Angeles
654:Kansas City
482:ShotSpotter
314:noise floor
283:focal plane
275:triangulate
177:World War I
141:microphones
1330:Categories
1247:2018-05-31
1197:2018-05-31
1171:August 26,
1000:2010-02-10
948:2020-11-17
920:2020-11-17
895:2020-11-17
727:See also:
477:helicopter
469:backfiring
303:backfiring
262:shock wave
54:improve it
662:Milwaukee
473:fireworks
101:Boomerang
1371:Firearms
1319:Fox News
1272:Archived
1094:Archived
808:See also
715:and the
650:Hartford
437:friction
368:Acoustic
361:infrared
299:firework
1346:Sensors
1297:Journal
1267:Reuters
1037:WBUR-FM
890:Reuters
747:FireFly
674:Oakland
646:Chicago
429:Optical
424:Optical
414:privacy
216:calls.
171:History
129:sensors
125:gunfire
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634:Boston
594:, but
349:Design
232:Alaska
1162:(PDF)
1071:Times
841:Notes
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678:Omaha
181:see:
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