A sensor determines the spin rate or rotation frequency of a munition body of a guided projectile relative to precision guidance munition assembly. The spin rate is used to determine launch velocity of the guided projectile early in flight before GPS is operationally active. The launch velocity is used to determine whether a corrective maneuver is needed to change the range of the guided projectile. Logic can control the canards on the canard assembly in response to the determination that a corrective maneuver is needed.