Array Acoustic Signal Processing in Shallow-Water Channels under Conditions of a Priori Uncertainty: Estimates of the Efficiency Loss

The objective of this study is a comparative analysis of the efficiency of the matched-field and optimal spatial signal processing methods in a shallow-water sound channel under conditions of inaccurate knowledge of its parameters. It is assumed that a signal of a remote localized source is received by a vertical antenna array against the background of an intense interference, which is also created by a localized source, while the vertical profile of the sound velocity, the channel depth, the sound velocity in underlying bottom, and its density are known with arbitrary deviations from actual values within specified intervals. The processing efficiency is characterized by the array gain in terms of the signal/(noise + interference) ratio normalized to the number of the array elements. The stochastic modeling technique is used to show that with an increase in the a priori uncertainty in the estimation of these parameters, the efficiency losses for these two processing methods not only have significantly different values, but can reveal the nonmonotonic character. The permissible error levels in the estimation of the channel parameters are determined, at which the gain loss does not exceed the specified level (3 dB) for each of the methods. The results are important to specify the requirements for facilities of operational oceanography that provide the effective operation of receiving antenna systems in real shallow-water conditions.