Projectile tracking system

Abstract

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 typically 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 detection mode, the system searches for the infrared signature of the 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 laser radar system provides a 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 projectile trajectory information and to determine the 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.