A Line Spectrum Estimation Method of Underwater Target Radiated Noise Base on the 1½D Spectrum

A line-spectrum estimation method of underwater target radiated noise is studied, and the method is based on 1 1/2 D spectrum. The characteristic of 1 1/2 D spectrum is analyzed. Using 1 1/2 D spectrum, the gauss-white noise and symmetry distribution noise can be reduced, and fundamental frequency can be strengthened and non-coupling phase harmonic wave can be eliminated. The characteristic and calculating process of Lofargram is introduced. The calculating method of 1 1/2 D spectrum diagram is introduced with analyzing the characteristic of Lofargram and 1 1/2 D spectrum diagram. The line in the 1 1/2 D spectrum diagram can be transformed into peak value in the Radon-domain using Radon transform. After the peak value is gained, the frequency and frequency modulation can be calculated. At last, Simulation results show that this algorithm is effective.