New target detection method using multi-path information in an underwater waveguide environment

Interface scattering in the ocean environment consistently results in reverberation and multipath echo, thereby decreasing the detection probability of moving targets. In this work, a new detection method which fully uses underwater acoustic channel characteristics to realise high detection probability for moving targets is proposed. First, this method combines fractional Fourier transform and fractional convolution theory to build a delay time–Doppler shift matrix related to multipath echoes. Second, the insensitivity of linear modulated frequency signal and distribution of multipath echo analysis are utilised to detect the moving target in a severe environment. Simulation results show that the proposed method can obtain higher detection probability and more accurate parameter estimation than the traditional method. Experimental results also verify that the proposed method has favourable performance even in strong reverberation environment.