On the Possibility of Increasing the Noise Immunity in Detecting Sound Signals in a Shallow Water Using Energy and Phase Invariants

Differential equations are obtained and analyzed to describe the dynamics of "ridges" constructed from zones of interference maxima and sound pressure equal phase lines. It is shown that these lines not only do not coincide in direction, but are nearly orthogonal in some areas. In this case, the dimensionless parameters that govern the dynamics of both ridges and equal phase lines are stable, and at distance and frequency ranges with a constant number of modes, they hardly depend at all on the frequency, waveguide properties, and receiver and emitter depths. This allows us to consider as invariant not only the well-known Chuprov parameter constructed on the intensity field, but also the parameter governing the direction of lines of equal signal phases on the phase plane. The predictability of these dependences makes it possible to efficiently accumulate signal power along these lines and increase the signal-to-noise ratio. It is shown that the spectral components calculated along lines of equal phases are added coherently, and when added along ridges, the videos are added coherently-the spectral power estimates are combined. The article also analyzes anomalous phenomena both in the intensity field and phase plane. The fundamentally different physical nature of the anomalies for lines describing the dynamics of ridges or equal phase lines is explained.