Patent ID: 7929375

Claim:
A method for improved active sonar, said method comprising: providing an excitation waveform x(t); providing a measured channel response z(t); filtering the excitation waveform x(t) using a plurality of Eigen filters generated by a Singular Value Decomposition (SVD) of the covariance matrix of the excitation waveform, where the SVD produces all the eigenvectors with their eigenvalues; constructing a nonlinear basis set to determine the kernel estimates of a Volterra-Hermite series expansion of the eigenvectors, where the basis set is a nonlinear no-memory device and the order of the nonlinearity selected determines the number and combinations of filters that are required to compute the essential kernels for performing an accurate estimate of a modeled response, y(t); determining the coefficients for the modeled response, y(t) against the actual data measurements of measured channel response z(t) and minimizing the sum of squared errors, where the fitting model minimizes the sum of the squared errors between actual measurement and the modeled response y(t); utilizing the modeled response and coefficients to obtain an accurate channel estimate; receiving actual active sonar return signals; and utilizing the channel estimate to remove channel effects from actual sonar signals to improve at least one of detection, classification and localization provided to an operator.