This paper mainly studies the extended self-similarity of the fractional Fourier transform (FRFT) spectrum of sea clutter and the application of the multi-scale Hurst exponent in FRFT domain to target detection within sea clutter.Considering that the parameter of the extended self-similar process—the multi-scale Hurst exponent can characterize the details of fractal signals in each scale

this paper studies the extended self-similarity of real sea clutter FRFT spectrum and its influencing factors based on real radar data.Then

the characteristic that the multi-scale Hurst exponent in the optimal FRFT-domain scale is relatively sensitive to the target is utilized for designing CFAR detection method within sea clutter.By the verification of real data

the multi-scale Hurst exponent in FRFT domain performs better in separating target from sea clutter than the mono-Hurst exponent and the multi-scale Hurst exponent in time domain.Additionally

because FRFT can effectively accumulate the energy of accelerating target echoes and promote the signal-to-clutter ratio

the proposed detection method has the potential for weak moving target detection within sea clutter.