Patent ID: 7852709
Filing Date: 2010-12-14
Classification: G01S

Abstract:
1. An active sonar system for detecting object(s) in water comprising: a transmitter, with an output connection, that generates a transmit signal and a conjugate of said transmit signal; a transmit transducer array, connected to said transmitter output connection, and configured to produce an acoustic signal in the water in response to said transmit signal; at least one hydrophone, with a hydrophone signal output connection, configured to receive said acoustic signal from the water and produce a hydrophone signal; a heterodyne stage having transmit signal and conjugate transmit signal inputs, connected to said transmitter output connection, and a hydrophone signal input, connected to said hydrophone signal output connection and a difference frequency signal output connection, configured to produce a difference frequency signal in response to the hydrophone signal and said transmit signal and said conjugate of said transmit signal; a frequency filter having connected to said difference frequency output of said heterodyne stage and having an output connection; and a display having an input connection connected to said frequency filter output connection and configured to display detection of said object(s) in water.