Series Adaptive Filter Method for Underwater Target Dynamic Line Enhancement

A novel series adaptive momentum filter based line enhancer(SAMFBLE), which includes two finite impulse response (FIR) filters, has been proposed. In the SAMFBLE, the first filter is a modified fourth-order cumulant based adaptive line enhancer (MFOCBALE) and its filtering coefficients are defined using fourth order cumulant diagonal slice of input signals and indirectly updated using input signals, function of input signals or sign of function of input signals, and energy power function of input signals. The second filter of the SAMFBLE is a momentum least mean square algorithm based adaptive line enhancer (MLMSBALE) and its filtering coefficients are updated using second order cumulants. Simulation tests with real data of the underwater moving target-radiated noise have shown that the SAMFBLE has immunity to Gaussian noise and that the ability of the SAMFBLE to suppress jointed distributed noise or non-Gaussian noise and trace time-varying signals is much stronger than that of the single MLMSBALE and the MFOCBALE