Recent instrumental developments at IFREMER
Thierry Terre
IFREMER
The Ocean Acoustic Tomography program (OAT) at IFREMER started during mid-80s shortly after the principle was proposed by Munk and Wunsch. It was the opportunity to be fainiliar with this new observation method using instruments developped in collaboration with Woods Hole Oceanographic Institution (WHOI), Webb Research Corporation (WRC) and IFREMER. This instrumentation, used in numerous short-range experiments (〜 300 km) is not adapted to basin scale studies (〜 1000 km). Studies in collaboration with Centre Militaire d'Oceanographie (CMO) regarding low frequency transducers demonstrated that the Janus-Helmholtz technology was a good candidate for basin scale experiment. IFREMER started to built a new modular instrument which could be used either as a source or a receiver or a transceiver. The instrument modules will be presented : source, receiver, long baseline positionning system, low power high stability clock. Preliminary results from the first deployment of this instrumentation in the oceanographic experiment CAMBIOS illustrate the presentation.
Thoughts on a simple receiver for ocean acoustic tomography
Bruce Howe
Applied Physics Laboratory University of Washington
A new, easy to use and low-cost acoustic receiver is required to supplement the present suite of equipment used in ocean acoustic tomography. The main requirements for such a receiver are (1) ease of use, (2) Iow cost, (3) accurate timing, (4) real time data transfer, (5) mooring position tracking, and (6) providing a signal for an acoustic source. We (APL and SIO) are in the process of designing and constructing a new receiver. The state of this effort will be described.
