Abstract: Disclosed is an apparatus for indicating the location in a measurement plane through which a projectile passes. The apparatus includes an array of at least three transducers responsive to the airborne pressure wave produced by the projectile and positioned at predetermined locations along a line parallel to the movement plane. The apparatus further includes a device for measuring the velocity of the projectile and another for measuring the velocity of sound in air in the vicinity of the transducers. A computing means, responsive to the array of transducers, the velocity measuring means and the propagation of sound determination is provided which determines the location in the measurement plane through which the projectile passed and provides an output indicating that location. Also disclosed is a means, in combination with the position detecting means, for detecting and providing a positive indication of a projectile hit on a target member.

Abstract: A target apparatus, having a framework covered by sheets of material to form a chamber the sheets of material being penetrable by a projectile, such as a bullet, fired at the target. A plurality of transducers are positioned at respective spaced-apart locations within the chamber and lying on an arc of a circle, for detecting shock or pressure waves in the chamber caused upon penetration of the sheets of material by the projectile. Time differences between instants of detection of a shock or pressure wave by the transducers are measured, the location at which the projectile penetrated the sheet of material being determined from the time differences. Preferably, a bull's-eye or aiming mark is provided on the target, the center of which is aligned with the center of the circle on which the transducers lie. Apparatus is also disclosed for determining the speed of sound in air within the chamber, enabling the projectile penetration point to be determined with particular accuracy.