METHOD FOR DETERMINING DISTANCE TO TARGET Russian patent published in 2006 - IPC G01S5/18 

FIELD: hydro-acoustics, possible use for engineering noise direction-finding systems of various types.

SUBSTANCE: method for determining distance to target, direction to which is being searched for by passive hydro-acoustic means, includes mounting an antenna for receiving oscillation speeds mutually perpendicularly to pressure antenna. Then, simultaneously, receipt of signals is performed via pressures channel and oscillation speeds channel, temporal delay is introduced in oscillating speed channel. Then, value of delay in this channel is determined, which is appropriate for maximal value of spatial-temporal correlation function between voltages in both channels. On basis of detected time and known values of expansion speeds for both processes in environment, target value is determined.

EFFECT: increased speed of operation and exclusion of a priori information on basis of classification characteristics of target while maintaining concealment.