Calibration of a high-power, low-frequency, parametric array designed for ocean environments

Guigne International Limited (GIL) in association with Defense Research Establishment Atlantic (DREA), has designed and built a high-powered parametric array transmitter operating at a center frequency of 100 kHz. The parametric array will be integrated into DREA’s bottom-tethered Wide Band Sonar (WBS) and used to collect environmental acoustic data in littoral waters. This paper presents the results of a calibration experiment performed at DREA’s acoustic calibration barge in Bedford Basin, Halifax, Canada. The data were compared to literature models for the near-field and the far-field of a parametric array. The results indicate that the interaction zone of the array is confined to the near-field and that the array approaches the limit of non-linear absorption; however, small-signal absorption plays a non-negligible role. Using a source level of 232 dB at each primary frequency, parametric array gains of −65 dB to −40 dB were measured at difference frequencies ranging from 1 to 10 kHz. The full beam wid...