Projectile tracking system

Abstract

The present invention provides a projectile tracking system for acquiring and precisely tracking a projectile in flight in order to reveal the source from which the projectile was fired. The source is revealed by the back projection of a 3-dimensional track file. The system is particularly suited for tracking a bullet fired by a sniper and identifying the location of the sniper. Projectiles of interest are typically traveling at a substantial fraction of the speed of sound or even faster than the speed of sound and therefore become hot due to aerodynamic heating. A telescope focuses infrared light from a relatively large field of view on to an infrared focal plane array. In a projectile detection mode, the system searches for the infrared signature of the fast moving projectile. The telescope's field of view is steered in the azimuth by a step and stare mirror which is driven by an azimuth drive motor mounted on the frame. When a projectile is detected the system switches to a tracking mode and the mirror is steered by the azimuth drive motor and a pivot motor to track the projectile. A short pulse high repetition rate laser in a laser radar system provides a pulsed laser beam which is optically coaligned with the telescope axis. Mirror angular position information, laser radar pulse travel time and the missile spot position on detector array are used by a computer to calculate bullet trajectory information and to determine the source or origin of the projectile using known ballistic trajectory methods. Although only a small portion of the total trajectory may be captured, the very accurate position information permits extrapolation to determine the launch point of the projectile.