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A snapshot of gunshot detection technology

A technology to detect gunshots in such situations can prove invaluable to police.

On November 26, 2008, at around 8.30 p.m. 10 men in inflatable speed boats came ashore at two locations in Colaba, Mumbai. They split into small teams.
Two of them who seemed like good looking college boys walked into “Leopold Cafe and Bar” at Colaba which was bustling with cheerful customers while another youthful team of two took a taxi to the CST railway station. Both the teams came equipped with AK-47 and hand grenades. The raucous customers guzzling beer and digging into delicious food at the Leopold cafe and the people at the CST rushing to the trains and getting off the train to go home had no clue of being sprayed with bullets from AK-47s the way pest control employee exterminates cockroaches by spraying with pesticides.

The first responders were the Mumbai police. Initially, they thought they were responding to a gang war, an underworld shoot-out. They therefore had lost the plot. They had no inkling they were against AK-47s, a fedayeen attack by Lashkar-e-Taiba and not an underworld shoot-out. An underworld shoot out would not have involved indiscriminate firing at innocent public with AK-47s. The attackers killed ten people at the Leopold cafe and 58 persons at the CST. If only the Mumbai police had known in the beginning stages that the attackers were indiscriminately firing from AK-47, they would have known they were not confronting the underworld but the terrorists, and their response would have been different. They would not have lost the plot.

Indiscriminate and mass shootings create havoc, in just a few seconds they can let a situation go out of hand without a plan or clear direction from police.

A technology to detect gunshots in such situations can prove invaluable to police. The gunshot locator can recognise the weapon from a sniper to a pistol to an automatic assault weapon like an AK-47. It can identify different gun sound signatures. It identifies the gunshot by detecting, locating and alerting the police.

Within its area of coverage, the technology can provide information to the police on the number of shots fired, the direction in which someone fired it and the number of weapons involved. Gunshot detection technology comprises a system of sensors that work jointly to calculate the location of a gunshot.

A gunshot recognition system called “ShotSpotter” system set up in Washington, DC, has successfully had the police counting on it to detect gunfire in its coverage area. In 2008, Washington, DC Police Department reported that it had helped track down 62 victims of violent crime and assisted in 9 arrests.
Besides assaults, the system also detected a good deal 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 to cover nearly a quarter of the city. In August 2017, the United States Secret Service tested the ShotSpotter technology to protect the White House.

In another scenario, in the backyard of Wilmington, USA one late Sunday night a series of gunshots pierced through the darkness. An operator 3,000 miles away in Mountain View, California watched his computer screen blip on a map. In a fraction of a second, it flashed the origin of the sound to Wilmington police, and patrol cars were on their way to the scene. When they reached the scene, they found the victim alive with bullets pumped in his hand and chest, just a few yards from where the gun had gone off. Installation of a gunshot recognition contraption called “ShotSpotter” in Wilmington which is basically a series of acoustic sensors appears to have distinctly helped the police gain an upper hand over gun violence. However, San Antonio, Texas discontinued its $500,000 ShotSpotter service, after finding it had only resulted in four arrests.

Gunshot technology appears to have evolved because in the early 1990s, crimes besieged the areas of East Palo Alto and eastern Menlo Park in the USA. East Palo Alto had 42 homicides and was turning into murder capital of the US. Residents of Menlo Park often called the police department to investigate reported gunshots but there was no way to determine the source. In 1992, John C. Lehr a seismologist at the US Geological Survey developed a method of locating gunshots. He recognised that sound waves traveling through the air away from a gunshot are basically similar to the sound (seismic) waves traveling through the ground away from an earthquake.

Seismologists have long known that by precisely measuring the different times of arrival of a seismic wave at several distant locations, it would be possible to pinpoint an earthquake's exact source. He installed a network of five radio-telemetered microphones around one of the gunshot-terrorised neighbor hoods. He radioed sounds from these microphones to a personal computer running earthquake-detection programs. After only a few weeks of testing and improving the software, the system was locating many signals associated with gunfire. Site testing of the system inspired by earthquake technology began in Redwood City, California, in 1995. During the trials in 1996, police officers fired.38-caliber pistol and 12-gauge shotgun blanks from various places in the City. During the tests, the system could pinpoint within 50 or 60 feet the locations from which they had fired blanks.

The gunshot detection technology was first researched during World War 1. Raytheon a major U.S. defence contractor developed a system which they used in Afghanistan and Iraq to pinpoint sniper fire and alert soldiers in the field. Acoustic gunshot detection systems (AGDS) today are being deployed at cities, airports, hotels, schools, and colleges to name a few locations. AGDS are of different types; some send audio to the command centre for analysis; some sensors come with in-built audio analysis. This technology came into spotlight on October 2, 2017, when a gunman killed 58 people and wounded hundreds in Las Vegas.

AGDS reduces police response times by detecting gunfire incidents and triangulating their precise location enabling police to get to the scene of gunfire faster than they would have to rely on control room calls. By doing so, they increase the likelihood of catching the people who fire guns by getting them before they can escape from the scene and by enabling police to collect evidence such as shell casings or interview the witnesses at the scene. This would lead to a decrease in gun violence, as catching gun offenders would take them off the streets and deter others from using guns in areas covered by AGDS.

Quick response of the police to gunshot victims could save lives by facilitating expeditious medical help for the injured victims. AGDS improves police-community relations by allowing police to go to places that detected gunfire and have positive interactions with them. In gun violence cases reporting rates are often low, particularly in places where people don't have adequate faith in police. AGDS helps generate data on gunfire in such places. Armies use a similar technology to overcome enemy snipers. In war zones, the technology finds a hidden sniper using the sound of the gunshot. Police also use this system to protect locations attractive to terrorists such as crowded malls, places of worship, and nuclear power plants.

The most popular gunshot recognition systems are outdoor and fixed. We would need a network of 10 to 12 sensors per square kilometre. They are best placed on top of buildings to make them unobtrusive to avoid detection and to increase effectiveness. They do not reveal the exact location of sensors to prevent vandalism. There are mobile solutions available;which can move from one area to another depending on the requirements. Indoor systems are being installed at several places.

For instance, Charleston International Airport in South Carolina was the first airport to install an indoor system to a portion of the passenger terminal. Spate of shooting incidents in the schools in the USA has made the school authorities think about gun recognition systems. In Wisconsin, the Kenosha Unified School District is the first to have approved the installation of gunshot recognition sensors at its 43 schools. The police get alerted as soon as someone fires the gunshots, simultaneously the doors get locked and the surveillance cameras get turned on streaming live feed to the authorities.

The Center for Development of Advanced Computing (CDAC) in India has indigenously developed a system that is low priced. Making it affordable to instal in large numbers in places such as borders. Police can use it for counter-insurgency and combing operations, surveillance of high security installations, and to collect forensic evidence after gunshot incidents. At the Tamil Nadu Police Academy, in Chennai, a team from Madras Institute of Technology in 2013 successfully tested a technology which could pinpoint the origin of a gunshot and direct a drone or Unmanned Aerial Vehicle (UAV) to the location.

The researchers used an advanced sound sensor on the UAV to calculate the precise coordinates of the source of the gunshot. If a sniper fired a bullet from an unknown location at a VVIP in a crowded place, the acoustic sensors, if installed in the vicinity, would instantly detect the place from where the bullet came. As a countermeasure, a multi-sensor drone fitted with cameras could zoom down to the source of the gunshot and even keep track of the shooter while beaming video feed in real time to the command centre. Besides conveying incident alerts, they also can relay their alert data to video surveillance systems in real time.

The combined audio and video information could be tagged and stored for subsequent use as forensic evidence. The acoustic sensor aboard the UAV could also detect specific sounds such as the noise of a jeep in a forest. Forest officials can also use such drones for tracking unauthorised persons or poachers or vehicles in prohibited areas such as reserve forests.

Just as how the gunshot detection systems detect the origin of the gunshots, human beings can detect their true essence through contemplation, which in turn can lead them to a place of oneness, a place of love, a place of being fearless, and a place of joy and happiness.

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