Inductive Telemetry on a Deep Ocean Surface Mooring.

Abstract

A long term engineering test of ocean data telemetry using inductive coupling is being performed offshore Bermuda as part of the ONR-sponsored Atlantic , Long Term Oceanographic Mooring (ALTOMOOR) program. Inductive modems are general purpose telemetry devices which can be used with standard, plastic-jacketed steel mooririg lines to transmit data between instruments in the water column and a receiver in the surface buoy. The advantage of inductive coupling over electrically connected instrumentation is that expensive and unreliable electro-mechanical cables and terminations are not needed to accomplish real time data telemetry. The modems send and receive data via toroids clamped around the wire which act as single turn transformers. Data telemetered up the wire are sent at a rate of 1200 b/s; commands are sent down the wire at 300 b/s.

A Self-Deploying, Depth-Adaptive Coastal Oceanographic Mooring

“…With most of the current XMOOR units, inductive telemetry (Frye et al 1993; at 1200 baud has been used for internal communication of data from subsurface sensors to the surface command and control unit. Inductive telemetry is based upon the transformer concept, where the primary is a split ferrite core with multiple turns clamped around the mooring wire, and the secondary is the mooring line, a 3/16 in.…”