From July to October of 1990 the Applied Tomography demonstration of near-real-time processing was conducted in the North Atlantic between Bermuda and North America. The highly variable eastward extension of the Gulf Stream Current was of particular interest. Acoustic transmitters placed on the bottom near Bermuda transmitted every four hours, and at times every 40 minutes, to IUSS hydrophones north of the Gulf Stream. Special hardware was developed to beamform, replica process, and relay the results to APL in an unattended near-real-time mode of operation. The results produced consistent and trackable paths of acoustic energy that were used to monitor the position of the Gulf Stream with high precision. Collaborators included the University of Michigan, the Scripps Institution of Oceanography and the Fleet Numerical Oceanography Center. The work was sponsored by the Office of Naval Technology.
The Applied Tomography Experiment of 1990, APL-UW TR9106, 28 February 1991.