Detection of underwater objects based on spectrum analysis of laser interference signals

A method based on the interference of the scattered laser beams carring acoustic wave information with a reference beam was proposed to facilitate the detection of underwater objects including submarines and sea mines. The spectrum analysis of the interference signals could eleminate the interfering noise influence in time-domain. This test system consisted of an underwater acoustic source, a precise optical detection device, and data acquisition and processing components. The experiment results proved that underwater acoustic signals with a frequency between 100 Hz to 300 Hz could be detected when the interfering noises were obvious. Proving adequacy of relevant theory and simulation process as well as practicability of this method.