Single hydrophone, passive ranging of tonal sources in shallow water using the waveguide invariant

A statistical method is presented for estimating both the value of the waveguide invariant, β, and the range to a tonal source in shallow water environments. This method requires minimal a priori environmental knowledge. A maximum-likelihood estimate of β is obtained from spectral analysis of a received signal from a tonal source over a known track. The range to a separate tonal source transiting the same shallow-water area is then estimated through a similar maximum-likelihood method, with the additional requirement of a range rate estimate. A recently published technique for estimating range rate through analysis of interference patterns of cross-correlated received time series is compared to a grid-search technique, in the context of evaluating performance of the range estimator. Both simulated and experimental results are presented. Simulated data were obtained using Kraken normal mode code. Experimental results used data from the Swellex ’96 (SW96) experiment. The negative impact of incorrect estimat...