Abstract: A projectile comprises an elongated casing containing a payload, a proximity fuze, a transmitter unit operative to transmit a beam of radiation toward a target, and a receiver unit responsive to radiation reflected from the target for controlling the proximity fuze to selectively initiate operation of the payload at a predetermined distance from the target. The transmitter unit is located adjacent the tail end of the projectile rearward of the payload and comprises a pyrotechnical charge positioned at the extreme rear of the projectile and operative, when ignited, to cause emission of light via a lens in an opening in the side of the projectile to form the transmitted beam of radiation. The receiver unit is located adjacent the nose end of the projectile forward of the payload to maximize the measuring base between the transmitted and received beams of radiation, and comprises an optical system associated with an interference filter, radiation detector, and electronic control circuit.