Patent ID: 6600694
Filing Date: 2003-07-29
Classification: G01S

Abstract:
A method for producing a decoy signal to enable a target to avoid a homing torpedo that uses a sonar ping signal for homing in on the target, comprising the steps of:receiving sonar signals with a transducer that produces electrical signals corresponding to the sonar signals; determining whether the electrical signals have frequencies that are within a defined frequency range; processing the electrical signals to determine whether they correspond to sonar ping signals; calculating an estimate of the torpedo's motion; calculating a transmit time for transmitting a decoy signal; calculating a Doppler frequency for the decoy signal such that the decoy signal will appear to the homing torpedo to be a return pulse from the target; and switching the transducer to a transmit mode to transmit the decoy signal having the calculated Doppler frequency at the calculated transmit time.