The effect of internal waves on matched‐field processing

The performance of matched‐field processing is degraded because of randomness of the propagation medium. Simulations and theory specialized to the Bartlett processor are used to study this type of environmental mismatch. The purpose is to quantify the effects of deep‐water internal waves on matched‐field processing. This is done at three different levels of approximation. First, the case of an ocean waveguide with a quadratic average sound‐speed profile and vertically stationary sound‐speed fluctuation statistics with Gaussian correlation is examined. Next, approximations are introduced so that a relatively simple analytic model can be abstracted from the theory. Finally, vertically nonstationary fluctuations obtained from a realistic, dynamic internal wave model are considered. In this case, a realistic average deep‐water sound‐speed profile, consistent with the internal wave field, is used. The results are found to agree with the predictions of the analytic model when the effects of multipaths are unimportant.