Extraction and analysis of line spectrum characteristics of underwater glider self-noise

Abstract

Autonomous underwater gliders (AUGs) are autonomous vehicles that propel themselves by changing their buoyancy through the ocean. For ocean observations, AUGs have unparalleled advantages that can operate in all weather conditions, for long time periods, and in remote locations. However, AUGs have limitations such as instrument and flow noise, which are undesired. To obtain the valid information from the AUG self-noise, we firstly introduce the noise source and basic characteristics of self-noise. Then in Aug 2016, sea trial of the hydrophone-equipped Petrel II Glider was conducted on the South China Sea and take the observation data in the 1000-meter depth range as the research object. Experimental results show that the self-noise measurement system has good stability. Mechanical noise contributes most to the self-noise, and the different motor contribution of Petrel II Glider under different working conditions is obtained by the step-by-step operation method. Finally, through extracting the line spectrum under different working conditions, the detailed characteristics of selfnoise is obtained and can provide some guidance for acoustic design and fault detection.