Multidelay Model Relating Tide Height to Underwater Acoustic Phase

Observed relationships between environmental parameters and underwater acoustic phase were earlier reported and a multi‐input nonrealizable model was analyzed showing that, among several parameters, tide height has the strongest coherence with measured phase fluctuations. This work is concerned with a special case of the above model, where the system is single input, with a realizable impulse response consisting of few delays. Several cases are considered such as a single delay, two or more delays. Among these, a special case is found where one of the delays is fixed at zero time (in phase, no delay component). Two kinds of results are reported—one where optimization is carried out on all energy bands, another where optimization is carried out on selected bands that are least corrupted by noise and the effect of other parameters. The resulting transfer function is calculated and errors from measured values are given individually for each band and also collectively as a figure of merit for that solution. [...