Phase feature extraction of echo for point target

In order to correctly recognize underwater target in noise environment, a new method of feature extraction of target echo phase is proposed in the paper. Waveform design of difference frequency and processing of phase feature extraction are given, including sub-band correlation and frequency scaling shift. And the influence of Doppler frequency shift from moving target is theoretically discussed. The method is verified by using surface echo data from computer simulation and pool trial respectively, and results show that phase feature can be accurately obtained when SNR is greater than 5dB.