You are walking down the street with a friend. A shot is fired. The two of you duck behind the nearest cover and you pull out your smartphone. A map of the neighborhood pops up on its screen with a large red arrow pointing in the direction the shot came from.
A team of computer engineers has made such a scenario possible by developing an inexpensive hardware module and related software that can transform an Android smartphone into a simple shooter location system.
For the last decade, the Department of Defense has spent millions of dollars to develop sophisticated sniper location systems that are installed in military vehicles and require dedicated sensor arrays. Most of these take advantage of the fact that all but the lowest powered firearms produce unique sonic signatures when they are fired. First, there is the muzzle blast–an expanding balloon of sound that spreads out from the muzzle each time the rifle is fired. Second, bullets travel at supersonic velocities so they produce distinctive shockwaves as they travel. As a result, a system that combines an array of sensitive microphones, a precise clock and an off-the-shelf microprocessor can detect these signatures and use them to pinpoint the location from which a shot is fired with remarkable accuracy.
Six years ago, the Vanderbilt researchers, headed by Associate Professor of Electrical and Computer Science Akos Ledeczi developed a system that turns the soldiers’ combat helmets into mobile "smart nodes" in a wireless network that can rapidly identify the location of enemy snipers with a surprising degree of accuracy.
In the past few years, the ISIS team has adapted their system so it will work with the increasingly popular smartphone. Like the military version, the smartphone system needs several nodes in order to pinpoint a shooter’s location. As a result, it is best suited for security teams or similar groups.
Retired SWAT officer Kenneith Pance says, "It would be very valuable for dignitary protection. I’d also love to see a version developed for police squad cars."