System and method for detecting sound of underwater

PURPOSE: An underwater sound navigation and ranging system and a sound detection method thereof are provided to use a detected mixed sound signal and a vibration and noise signal, thereby improving underwater sound navigation and ranging quality by extracting a pure underwater sound signal. CONSTITUTION: A sensor apparatus comprises a sound sensor(106), a reference sensor(108), a housing(110), and a signal processing device. The sound sensor detects a mixed sound signal. The mixed sound signal comprises an external underwater sound signal generated from an underwater sound source and a vibration and noise signal generated from a moving body on/in the water. The reference sensor blocks the external underwater sound signal and detects the vibration and noise signal. The housing surrounds the outside of the reference sensor in order to block transmission of the external underwater sound signal to the reference sensor. The signal processing device extracts a pure underwater sound signal using the mixed sound signal and the vibration and noise signal.