Two-Dimensional High-Frequency and Mid-Frequency Hydrophone Arrays and Recording Systems

Two 128 element, two-dimensional hydrophone arrays and recording systems have been developed at the Marine Physical Laboratory for the continuous recording of HF/MF acoustic data at sea. These arrays have been deployed during a recent at-sea experiment aboard the research platform FLIP. Each of these arrays consists of 128 hydrophones with preamplifiers, a 128 channel signal conditioning and sampling electronics package, a 300 meter umbilical cable for power and data telemetry, and a dry-end recording system. At the dry-end, the acoustic data are GPS time-stamped, displayed in real time, and recorded to external Firewire disks. The systems automatically switch to a new disk when the previous disk is full and are capable of continuous recording. The technical details of the arrays and recording systems, the deployment procedure from FLIP, and the performance of the systems during the recent at-sea experiment are described