Spin-stabilized projectile and guidance system therefor

A guidance system for a spinning projectile, such projectile being in flight toward a target in motion, such system comprising:

• (a) ground-based means for illuminating the spinning projectile with a linearly polarized radio frequency signal;
• (b) radio frequency signal receiving means including a linearly polarized antenna affixed to, and rotating with, the spinning projectile for establishing a roll reference when the linearly polarized antenna is aligned with the linearly polarized radio frequency signal;
• (c) a seeker for continuously measuring the line-of-sight angle between the centerline of the spinning projectile and the line-of-sight to the target, such seeker having its boresight aligned with such centerline;
• (d) signal processing means, responsive to the outputs of the radio frequency signal receiving means and the seeker, for determining, in a first plane defined by the velocity vector of the spinning projectile and a line from the center of gravity of such projectile to the target and in a second plane orthogonal to the first plane, the rates of change of the line-of-sight between such projectile and target;
• and
• (e) course correction means carried on the spinning projectile to maintain the vector sum of the rates of change of the line-of-sight in the first and the second plane below a preset value during intercept.