Title: Broadband interference of received pulse for single normal mode and solitary internal wave localization

Author(s): PIAO Shengchun; ZHANG Shizhao; LIU Jiaqi; LI Xiaoman; IQBAL Kashif;

Affiliation(s): Acoustic Science and Technology Laboratory, Harbin Engineering University; Key Laboratory of Marine Information Acquisition and Security, Harbin Engineering University, Ministry of Industry and Information Technology; College of Underwater Acoustics Engineering, Harbin Engineering University

Abstract: To analyze the solitary internal wave (SIW) influence on acoustic field interference pattern and thereby monitor SIW, for broadband pulse signal propagating through SIWs, we adopt a parabolic equation model, and simulate the variation of received single normal mode (SNM) pulse sequence with SIW position, and analyze the spatiotemporal interference characteristics and mechanism of the sequence. Based on the coupled mode theory, we derive the relationship between SIW position and interference striation slope (ISS). The relationship can monitor the SIW position precisely, with greatly improved precision and robustness compared with previous work. Furthermore, based on the SNM interference pattern periodicity in frequency, we also develop another method to estimate SIW range, with better real-time property than the first method. The SIW-normal mode interference relationship can be used for improving acoustic field localization in the presence of SIWs, which has great value for oceanology, marine engineering, marine military and so on. Besides, the relationship can be expanded to other detection for local variation, e.g., detecting metal flaw and locating dramatic variation in seabed topography.