Abstract:
Geometric dispersion in the deep ocean sound channel causes wideband modal arrivals to be spread significantly in time at long ranges. This results in a low modal peak signal-to-noise ratio and interference due to multiple overlapping arrivals. These effects make the identification of individual modal arrivals difficult without the use of a vertical receiving array. The time compression of modal arrivals using phase-only filters is examined as a method for locating and identifying arrivals from a reception at a single depth. A search display, dubbed the dispersion diagnostic display, has proved its worth in computer simulations using a 60 mode range invariant model of SLICE89 propagation. The DD display simultaneously shows a raylike (no dispersion) structure and a patterned modal structure with strongly dispersed early arrivals and lightly dispersed terminal arrivals. [Work supported by ATOC.]