Estimation of ship´s extremely low frequency electromagnetic signature based on fuzzy fusion for target detection

The alternative electromagnetic (EM) fields radiating from a ship are widely recognized as new contributors to the application of underwater target detection. This paper focuses on the estimation of this extremely low frequency (ELF) signature from a fuzzy fusion enhancement aspect. Firstly, the ELF signature estimation problem is expanded to a fuzzy credibility solution issue, and a generalized multi-attribute fuzzy vector which represents each frequency points´ line spectrum characteristic is obtained by a statistical procedure on sensor´s instantaneous spectral analysis. Then, the fuzzy fusion method is applied to obtain the credible degree of each frequency point to be an ELF. Finally, threshold is set to extract ship´s truly ELF signature with largest likelihood and shield interference of the noise ELF signature. Experimental results show that the proposed algorithm has particular advantage in remote target detection.