### ASA 125th Meeting Ottawa 1993 May

## 4aUW4. Broadband localization and deconvolution.

**T. C. Yang
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*Naval Res. Lab., Washington, DC 20375
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An algorithm is presented for detecting and localizing a passive broadband
signal in an underwater acoustic waveguide. The processor estimates the modal
spectrum of a broadband signal for source localization; as a consequence, the
source spectrum and signature (time domain waveform) are estimated. (Broadband
modal decomposition is the equivalent of time domain deconvolution for source
signature extraction.) In addition to the usual lofargram, a frequency-depth
plot is proposed to display a broadband signal. Source localization is
conducted in the frequency domain by summing the (range and depth) ambiguity
functions over the signal bandwidth. Sidelobes are suppressed in broadband
processing if the signal has sufficient bandwidth. Coherent summation of the
ambiguity functions yields the expected time-bandwidth gain if source signature
is known (the extended matched filter processing). Numerical simulations are
shown for an Arctic waveguide. The processor works for transient as well as
continuous broadband signals.