Atlantic Long-Term Oceanographic Mooring (ALTOMOOR)

Funding was provided by the Office of Naval Research through ContractNos. N000-14-94-10346 and N000-14-90-J-1719.

The Atlantic Long-Term Oceanogrphic Mooring (ALTOMOOR) has been maintained offshore Bermuda since 1993 as a testbedfor the evaluation of new data telemetry technologies and new oceanographic instrumentation. It is currently a joint projectbetween the Woods Hole Oceanographic Institution and the University of Southern California This report documents the WHOIcontributions which have focused on the development of new data telemetry methods and new mooring technology. Details of theinstrumentation evaluations will be published separately.A new inductively-coupled telemetry technology for ocean moorings has been developed and tested on ALTOMOOR. Theinductive link uses standard, plastic-jacketed mooring wire as the transmission path for data generated at the individual instrumentsinstalled on the mooring. The signals are inductively linked to the mooring wire via toroids clamped around the wire, thusavoiding the need for multiconductor electromechanical cables terminated at each instrument. Seawater provides the electrical returnpath. The inductive modems send and receive data at l200b/s. A controller in the surface buoy collects data from each of thesubsurface instruments and forwards the data to shore by traditional satellite telemetry (Argos) and by short range radio using anearby ship as a store and forward node. The buoy-to-ship link operates over about 2 km at lOkBytes/sec. When the ship docks,data are offloaded automatically to a computer on shore which can be accessed via the Internet.