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Acoustic communication for the monitoring of current and vessel draft

This paper presents an overview of the DACAPO (Demonstration of Acoustic Communication for ADCP read-Out) sea trials, which took place on the Western Scheldt (Netherlands) in August 2005. The purpose of these trials was to acquire current profiles and to measure the draft of sailing bulk carriers. Such measurements must take place in the navigation channel, where the traffic itself prohibits the use of upstanding measurement poles or radio buoys. An arrangement was devised consisting of upward looking current profilers interfaced with high data rate acoustic modems, and a shore station with two hydrophone arrays to implement an adaptive beamforming receiver. Raw acoustic data were recorded for offline processing and quasi real-time integration in an existing infrastructure for sensory data. Periodic effects in the performance of the acoustic communication links reveal a strong influence of the tide.