A Device for Automatically Tracking the Roll Position of a Missile

Many short range missiles are guided in angle or range by optical means. Since these missiles are usually caused to roll in flight for stability reasons, some type of roll position reference device is necessary. The only type of roll reference device in use is a gyro, although various horizon scanners, Doppler, and optical methods have been considered. This paper describes an optical method of roll reference which utilizes the relative positions of two flares of different color attached to the rear of the missile. Since the roll position is known at the launch point, commands to the missile are commutated at the launch point rather than in the missile as is necessary when a gyro or other missile-borne roll reference device is used. Thus, the roll tracker removes from the missile two subsystems (gyro and commutator) while adding two components (two colored flares).