US Patent 9040885 Trajectory modification of a spinning projectile

The invention is a projectile, device and system having a roll control device which may be fixed or deployable, for providing torque counter to the spin of the projectile and providing drag on the projectile. The roll control device includes a guidance collar rotatably attached to the projectile located near a front end of the projectile wherein the guidance collar includes one or more guidance collar aero-surfaces shaped to provide torque counter to the spin on the projectile. The guidance collar aero-surfaces may be controlled by a brake and guidance electronics on the projectile. The invention also includes a body collar fixedly attached to the projectile aft of the guidance collar, wherein the body collar includes one or more body collar aero-surfaces and fixed or deployable drag devices. Another embodiment use only a guidance collar aero-surfaces to orient a fixed drag device relative to an Earth inertial reference frame to create asymmetrical drag on the projectile and thereby altering its trajectory.