System for recognizing signal of interest within noise
AssigneeTRW Inc.
InventorKathleen E. Powers
Life of this patent
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Abstract
A system for detecting a predictable time varying signal within a noisy environment. Rather than merely comparing the output of a matched filter implementation to a threshold, a parallel reference is also generated by autocorrelating the weighting function from the matched filter. The original output and this reference are both acted upon by a mathematical operator and the two then compared for closeness of fit using a Chi-Square Goodness of Fit Test, a Mean Square Error Test, or some other test for closeness of fit. A value indicates the closeness of the two curves and is then compared to a threshold to determine whether the signal of interest is present or not.
Claims21
An apparatus for detecting the presence of a signal of interest within a noisy input comprising:
- a matched filter for receiving said input and generating an output;
- an autocorrelation device for autocorrelating a function which is also applied to said matched filter as a weighting function, said autocorrelation device producing an output;
- a feature generator for performing a mathematical operation on the output of said matched filter and the output of said autocorrelation device and then producing two outputs;
- a comparison test device for receiving two outputs from said feature generator and performing a closeness of fit test to determine how close the two outputs are to each other and producing a comparison output indicating this closeness;
- and
- a decision circuit for comparing said comparison output to a threshold to determine whether the input signal is present or not.
A method for detecting the presence of the signal of interest in a noisy input comprising:
- performing a cross correlation between said input and a weighting function to produce a cross correlation output;
- performing an autocorrelation on said weighting function to form an auto-correlation output;
- performing a mathematical operation on said cross correlation output and said autocorrelation output to generate an observed generated signal and a reference generated signal;
- comparing said observed generated signal and said reference generated signal using a comparison test to determine how close the two signals are to each other and to generate a comparison output;
- and
- comparing said comparison output to a threshold to determine the presence of the signal of interest in the input signal.
An apparatus for detecting a signal of interest within a noisy input comprising:
- a matched filter for correlating said input with a weighting function;
- an autocorrelation device for autocorrelating said weighting function to produce an output;
- a comparison test device for comparing the output of said autocorrelation with the output of said matched filter to determine the closeness of the two outputs and for producing a value indicative of this closeness;
- and
- a decision device for comparing said comparison output with a threshold to determine whether said signal of interest is present in said input.
A method of determining the presence of a signal of interest in a noisy input comprising:
- performing a cross correlation between said input and a weighting function to produce an output;
- performing an autocorrelation of said weighting function to produce an output;
- performing a comparison test between the output of said autocorrelation step with the output of said cross correlation step to determine the closeness of the two outputs and for generating a comparison output indicative of this closeness;
- and
- comparing said comparison output with a threshold to determine the presence of said signal of interest in said input.
A computer program embodied on a computer readable medium and executable by a computer to determine the presence of a signal of interest in a noisy input, comprising:
- performing a cross correlation between said input and a weighting function to produce an output;
- performing an autocorrelation on said weighting function to produce an output;
- comparing the output of said autocorrelation step with the output of said correlation step to determine their closeness and to generate a comparison output indicative of this closeness;
- and
- comparing said comparison output to a threshold to determine the presence of said signal of interest in said input.
Dependencies are inferred from the claim text.