Agenda

Seminar Tadashi Ebihara (University of Tsukuba, Japan)

• Monday, 10 March 2025
• 15:30-16:30
• EEMCS, HB. 17.140

Underwater Acoustic Communication and Positioning in Shallow Waters

Underwater Acoustic Communication and Positioning in Shallow Waters

This study addresses the challenges of underwater acoustic (UWA) communication and positioning in shallow waters, which are characterized by significant delay and Doppler spreads. To provide a highly reliable communication, we propose Doppler-resilient orthogonal signal-division multiplexing (D-OSDM), which preserves orthogonality among data vectors even in doubly spread channels. Field tests, including MIMO configurations, demonstrate that D-OSDM enables reliable data transfer in mobile UWA environments with delay and Doppler spreads. Additionally, a new underwater positioning method is proposed for shallow waters, using direct wave arrival time groups and database matching. This method accurately measures baseline length from the impulse response of the UWA channel. Experimental trials in a harbor area showed positioning errors of about 0.2 meters and a near 0% missing rate, indicating the potential of this system for unmanned and remote underwater construction.