S. A. Stotts
N. R. Bedford
Appl. Res. Labs., The Univ. of Texas at Austin, P.O. Box 8029, Austin, TX 787123
An efficient and robust method has been developed to locate impulsive sources in an ocean environment. A sonobuoy field was first deployed in a ring-type pattern. GPS receivers were installed on the buoys to obtain their locations within a few meters of accuracy. Charges were then set off at arbitrary locations within the ring. High-resolution plots were used to obtain direct path and first bottom bounce arrivals on each buoy. A model grid of arrival times was constructed, corresponding to the dimensions of the buoy field. A ray model previously developed here at ARL:UT [E. K. Westwood and P. J. Vidmar, J. Acoust. Soc. Am. 81, 912--924 (1987)] was used to obtain model travel times. The minimum value of the least-square error between the real arrival times and the modeled travel times resulted in an unambiguous location of the source, within the limits of the grid spacing chosen. This value was calculated by picking one phone as the reference and then summing the errors of each phone relative to the reference. Successive iterations with finer grid spacings results in source location within the accuracy of the buoy locations. Results obtained at Lake Travis and the Gulf of Mexico will be presented. [This work is supported by Navy Strategic Systems Programs.]