Abstract: Pulse integration is utilized on board an optically guided missile or other ordinance device used as a part of a target designation system for extending the lock-on range of the missile by approximately 18%, when a double pulse laser is utilized to illuminate and designate the target. Pulse integration is accomplished with a recirculating delay unit which superimposes the first pulse on the second pulse, such that while the pulses add coherently, noise does not add in phase. The pulse integration technique therefore enhances the signal-to-noise ratio when the missile is at the outer limits of its operating range. When the missile is sufficiently close to the target, doublet decoding is actuated to offer countermeasure resistance. At this point, pulse integration may proceed in lieu of doublet decoding or may be dispensed with in view of the increased signal-to-noise ratio due to the close range of the missile to the target.