Periodic Signal Detection in Ship Radiated Noise

Periodic signal is abundant in ship radiated noise. Its detection is an important step towards active control of ship's acoustic signature. Based on power spectrum analysis and DEMON analysis, an approach to detect line spectrum and modulation spectrum of ship radiated noise is proposed. Periodogram method is used for power spectrum estimation. The separation of line and continuous spectrum, false positive removal, and line spectrum merging are conducted to improve the quality of detected characteristic line spectrum. Via DEMON analysis, steady physical characteristics including propeller's rotational speed and number of blades are obtained. Finally, the effectiveness of the approach is demonstrated by simulation results.