Inductive Telemetry for Passive Acoustic Monitoring in the Ocean

This research paper presents the development of an inductive telemetry for autonomous underwater ambient noise measurement system for deep ocean environments to gain the noise variability and noise field in deep ocean region. In view of this, the development of the ambient noise system along with inductive telemetry has been taken-up. The paper discusses a comprehensive overview of inductive communication techniques, design consideration, system architecture, components and their integration. The measurement system consists of two parts. The subsurface system incorporates hydrophones interfaced with the Data Acquisition System (DAQ) with storage, data processing and transmission capability. The surface system receives the processed underwater noise data through inductive communication. A pair of inductive modems is employed for the transmission and reception of the data over the mechanical inductive mooring cable between the subsurface and surface system. A LabVIEW-based software is developed for measurement, processing, data transmission and reception. A preliminary laboratory study has been carried out with inductive telemetry at Acoustic Test Facility of NIOT and successfully validated with the known source transmission.