| Summary: | Matched-field processing (MFP) is a technique for tracking an acoustic source in range and depth by comparing the output of an ocean acoustic propagation model with measured acoustic data collected across multiple hydrophones. In October 2003 a MFP experiment was conducted using humpback whale sounds recorded during the spring migration off the Sunshine Coast in Queensland, in conjunction with a larger experiment conducted by the Humpback Acoustic Research Collaboration (HARC). Humpback whale sounds with frequency content between 50 Hz to 1 kHz were recorded on a fivehydrophone vertical array deployed in 24 m deep water near Noosa, Queensland. The vertical array consisted of a set of flash-memory autonomous recorders attached to rope with an anchor at one end, and a subsurface float at the other. Acoustic data were simultaneously collected and monitored on five sonobuoys deployed over approximately 2 km range. The azimuth and range of the whale could be estimated via relative time-of-arrival measurements on the buoys. Using the range estimates as bounds on the matched-field processing, a inversion using the calls was performed on the vertical array data using a genetic algorithm. Inversion parameters included animal range, depth, and array geometry. Preliminary results of the inversion and resultant 3-D position fixes are presented. [Work supported by the US Office of Naval Research, Ocean Acoustic and Marine Mammal Programs].
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