A missile guidance system having two control modes alternatively controlling the thrust vector of the missile. The first control mode provides turning commands for substantially aligning the missile towards an airborne target, and the second control mode controls the missile on a homing path in pursuit of the target once the missile is aligned. A threshold detector operates switches for selectively enabling the control modes, where the first mode is enabled at an angular rate of the target line-of-sight above a predetermined threshold and the second mode is enabled at a light-of-sight rate below the threshold. The first mode provides thrust vector control signals corresponding to a signal sum of the component angle signals of the line-of-sight emitted by a narrow field of view infrared sensor mounted on the missile and continuously locked on to the target, angular rate signals of the line-of-sight, and acceleration signals emitted by an accelerometer having orthogonal sensing axes normal to the line-of-sight. The second mode provides thrust vector control signals corresponding to the difference between the signal sum of the first mode and accelerometer signals emitted by an accelerometer mounted on the missile having orthogonal sensing axes normal to the missile.
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