Two-step adaptive line enhancer for ship-radiated noise line spectrum detection

Line spectrum in ship-radiated noise is widely used in ship target recognition, for which can represent the essential feature of ship. So detecting ship-radiated noise line spectrum is significance in target recognition. A two-step adaptive line enhancer (TS-ALE) is proposed to improve the accuracy of line spectrum in ship-radiated noise under the background of ocean noise in the paper. The difference between delay of input signal and error signal of the first ALE is acted as input of the second ALE, compared with the tradition one step ALE (OS-ALE). The method can separate the ship radiated noise line spectra from the broad band background noise under low SNR of input signal, while OS-ALE cannot. The simulation results and experimental results show that the proposed TS-ALE outperforms the traditional OS-ALE in the low SNR and wideband noise scenarios.