### ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

## 2aUW29. Target range and depth estimation from surface multipath.

**James A. Doutt
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*Dept. of AOPE, Woods Hole Oceanographic Inst., Woods Hole, MA 02543
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**Edward H. Hug
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*Old Ironsides, Inc., New London, CT 06320
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The range and depth of a target are determined and compared with the known
depth and the range as derived from differential GPS navigation. The data
consists of a single return from a monostatic sonar configuration. The method
uses a cost function defined as the sum of the squares of the differences
between the arrival times measured from the data and those predicted by ray
trace for an assumed target depth and range. The depth and range are then
varied so as to minimize the cost function. Only the direct and
surface-reflected paths have been used. However, the method is easily
generalized to use more arrivals if the bottom depth is known and
bottom-interacting arrivals can be identified.