Very long-range source localization with a small vertical array

Several processors are developed and used to perform source localization on the 3250-km San Diego–Hawaii path of the Acoustic Engineering Test (AET). Associated simulations are done to test the range-frequency limits of coherent matched-field processing using PE modeling through a simulated internal-wave environment. The AET experiment is presently well beyond the range of effective coherent matched-field processing. A mode filter was developed to extract 60 complex mode amplitudes from the data received on the 20-element vertical line array. A mode space depth estimator successfully localizes the source. A mode arrival time difference range estimator is developed and found to be biased by internal-wave induced mode coupling. The final processor developed utilizes the stability of early arriving wavefronts to determine the source range by matching wavefront arrival patterns.