Optoelectronic Instrumentation Projectile Follower System For Ballistic Applications

Abstract

This paper covers the design and application of a state-of-the-art optoelectronic instrumentation system called the Projectile Follower System (PFS). This system is designed to produce high speed motion picture photographic or video records for investigating dynamic ballistic phenomena of ammunition during external flight. It is designed to be used for developing and testing U.S. Army ammunition and especially for high velocity projectiles fired from direct fire weapons such as tank guns. The fundamental operational concept is that the vertical axis of a rotatable mirror is driven synchronously with the motion of the projectile, and thus the projectile is maintained within the field of view of stationary motion picture or video cameras aimed at the mirror. The PFS incorporates microprocegsor and computer control to achieve angular accelerations of the mirror of up to 2,100 rad/s . The mirror is manufactured from beryllium using a honeycomb construction and has a 300 x 500 mm optical surface. It can also be used to provide auxiliary illumination by reflecting a beam generated from a stationary light source onto the moving projectile. Compared to a conventional high speed motion picture camera system, the PFS covers a far greater portion of the projectile's flight from a single camera station with a relatively larger photographic image size. The resulting photographs display a considerable reduction in blur. This paper describes the PFS optoelectronic engineering system design and application. Included are the mirror and its drive, control and drive electronics, projectile synchronization, muzzle velocity correction, projectile illumination, and cameras and related optics. The range installation, data recording methods, and future expansion capability are also discussed.