System and method for active sonar signal detection and classification
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsRichard A. Katz, Albert H. Nuttal
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Abstract
A sonar system and method are provided to extract and identify information about a particular target illuminated by an active sonar system. The present invention utilizes a Volterra Series Expansion in conjunction with a least squares procedure to estimate channel and target responses, which may be linear or nonlinear. The system estimates the channel and target responses for different orders of the Volterra Series Expansion and then selects the order for which a minimum error is determined with respect to a measured acoustic return signal. The system requires as inputs only the excitation waveform and the measured acoustic return signal.
Claims20
A method for detecting sonar signals, said method comprising:
- providing an excitation signal for in-water transmission of an acoustic signal;
- providing a response signal produced responsively to said in-water transmission of said acoustic signal;
- and
- determining a plurality of impulse responses utilizing said response signal and said excitation signal in a Volterra Series Expansion, said Volterra Series Expansion being sufficiently generalized such that said Volterra Series Expansion comprises a plurality of Volterra kernel orders and can include orders above a second-order Volterra kernel.
A system for detecting sonar signals, said system comprising:
- an acoustic signal transmitter for producing a transmitted acoustic signal, said transmitted acoustic signal being selected from any of a group of waveform transmission tyoes comprising frequency modulated signals, continuous wave signals and white Gaussian signals;
- an acoustic receiver, a received acoustic signal. produced responsively to said transmitted acoustic signal;
- and
- a processor joined to said acoustic signal transmitter and said acoustic receiver to utilize a Volterra Series Expansion comprising a plurality of Volterra kernel orders to compute a plurality of channel and target impulse responses.
A method for enhancing detection of sonar signals comprising:
- providing an excitation signal for transmission of an acoustic signal;
- receiving a return signal from said transmitted acoustic signal;
- determining an estimated channel response and estimated target response using a Volterra Series Expansion;
- comparing said estimated channel response and said estimated target response with said return signal to determine an error;
- and
- solving for Volterra kernels of progressively higher order.
Dependencies are inferred from the claim text.