Study on the impact of bubble curtain on underwater acoustic communication

Conference Name:OCEANS 2014 - Taipei. Conference Address: Taipei, Taiwan. Time:April 7, 2014 - April 10, 2014.Bubble curtain technology has been applied in underwater blasting engineering for decaying the sound wave. Applying it to underwater acoustic countermeasure (UAC) is bound to achieve certain results. So it is important and necessary to assess the effect of bubble curtain on underwater acoustic (UWA) communication. In this paper, we commence from the bubble resonance theory and apply the Bellhop ray model in analyzing the bubble curtain which damps the impact signal at different depths and bubble curtain ranges and verify the correctness of the model. With this method, we get the impact of bubble curtain on underwater acoustic communication based on frequency shift keying (FSK) modulation by simulation and laboratory experiment

Autocorrelation method for time delay estimation to calculate the source level of click signal for Sousa Chinensis

Conference Name:OCEANS 2014 - Taipei. Conference Address: Taipei, Taiwan. Time:April 7, 2014 - April 10, 2014.Like other dolphins, Sousa Chinensis produces click signals to echolocate in underwater. Research on the source level (SL) of click signal transmitted by Sousa Chinensis is beneficial to understand the survival and behavior of such animals. In the shallow sea where the Sousa Chinensis lives, the underwater environment is so complex that causes the click signals propagation to the receiving hydrophone at different times in different paths. In this paper, we introduced autocorrelation signal process analysis to calculate the delay time, predicted the source level base on the oretical sound wave attenuation rule in the sea. During May of 2013, the Click signals were recorded by a set of hydrophone system in shallow sea of Xiamen in China. The results show that the SL of Sousa Chinensis ranges from 166.9 to 199.6 dB peak to peak (p-p) re: 1μPa, and mean value is 180.05±8.93dB