Weak target detection based on fractal analysis under rada sea clutter background is an open problem. The existing methods, using single fractal dimension and Hurst exponent in time domain or Fourier domain, are not applicable under low signal-to-clutter ratio (SCR) conditions. Since autoregressive (AR) spectrum has the advantage of high-frequency resolution over the Fourier spectrum in sea clutter analysis, while multifracal theory is an extension of single fractal analysis. Therefore, we combined the multifractal analysis with AR spectrum estimate theory. Since singularity intensity function is an important parameter to describe a multifractal set, this paper proposed a weak target detection method based on singularity intensity function of AR spectrum under the sea clutter background. Then real S-band data sets are used to analyze the singularity intensity function of AR spectrum, and the results show that the AR singularity intensity function between sea clutter and targets has different value range interval. Finally, the singularity intensity function width of AR spectrum is taken as a statistical test for weak target detection. Compared to the existing fractal methods method, the proposed target detection method improves the detection probability over 20% in low SCR condition.

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SummaryIn order to meet the needs of the application of optical detection and recognition of ship targets in complex sea environment, based on the full link of optical remote sensing detection, the radiation transmission mechanism of ship target characteristics is analyzed. Then, the radiation characteristics model of ship target, the radiation model of ship target thermal wake, and the radiation characteristics model of sea background are established, and the simulation calculation of focal plane radiation characteristics for sea surface ship target is realized according to the space‐based detection and imaging mechanism; Finally, based on the simulation calculation model, the variation law of ship target radiation characteristics under different sea surface conditions and different imaging time are analyzed, which can provide theoretical basis and scientific guidance for the key index design of Space‐Based Surveillance and detection system and the optimization of target detection and recognition algorithm.