Moving target detection at sea based on fractal characters in FRFT domain

In order to effectively detect moving target in sea clutter, three methods based on fractal character differences are proposed making use of the different fluctuation of amplitude between sea clutter and moving target in fractional Fourier transform (FRFT) domain. At first, fractal model in FRFT domain is established and simulations of fractal curves of real sea clutter in FRFT domain are conducted, which indicate the fractal character i.e. self-similarity within its corresponding scale-invariant interval. Then, fractal dimension, fractal fitting error and fractal dimension variance in FRFT domain are analyzed, whose differences can be used as test statistic for moving target detection respectively. In the end, X-band real sea clutter is used for verification and results present that the proposed methods outperform the traditional coherent accumulation method and fractal dimension difference method in time domain. Weak moving target can be detected, which indicates the effectiveness of the methods.