SONAR-DOPPLERSYSTEM FOR FARTYG

摘要

An acoustic lens for marine doppler sonar apparatus of the type in which acoustic energy is radiated and received along a beam directed at an angle with respect to a ship's axis is fabricated so as to have an external surface substantially flush with the ship's hull and an internal surface angularly disposed with respect to the external surface. Electro-acoustic transformation elements are mounted on the internal surface. The lens material is selected to have an acoustic propagation velocity greater than that of water so that acoustic signals are refracted in passing across the lens-water interface. The lens prevents spurious acoustic signals that would ordinarily be reflected from the aerated water close to the ship's hull from reaching the electro-acoustic transformation elements.