Systems Engineering and Electronics ›› 2023, Vol. 45 ›› Issue (12): 3806-3818.doi: 10.12305/j.issn.1001-506X.2023.12.10

• Sensors and Signal Processing • Previous Articles    

Numerical investigation on the spatial ergodicity of ocean radar scattering and sea clutter amplitude statistical characteristics

Yanlei DU1, Xiaofeng YANG1,*, Sheng WANG1, Junjun YIN2, Huizhang YANG3, Jian YANG3   

  1. 1. Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100101, China
    2. School of Computer and Communication Engineering, University of Science and Technology Beijing, Beijing 100083, China
    3. Department of Electronic Engineering, Tsinghua University, Beijing 100084, China
  • Received:2022-04-09 Online:2023-11-25 Published:2023-12-05
  • Contact: Xiaofeng YANG

Abstract:

The spatial ergodicity of sea surface radar scattering is one of the important foundations for conducting numerical simulations of sea surface scattering and analyzing the applicability of algorithms for different radar systems in ocean remote sensing applications. This paper numerically investigates the spatial ergodicity of radar scattering from randomly rough ocean surface and its clutter amplitude statistical characteristics. The rough sea surface models including all large-scale waves are firstly generated using the Monte Carlo method. Then, based on the accurate full-wave multilevel steepest decent-sparse matrix canonical grid (MLSD-SMCG) method and 2nd-order small slope approximation model (SSA-2), we simulate the L-band normalized radar scattering coefficients and sea clutters from one-dimensional and two-dimensional rough ocean surfaces with different radar illumination sizes. According to the simulation results, it is found that for radar incidence and scattering angle beyond the range of shading effect, the normalized and polarization radar scattering coefficient from rough ocean surface with radar illumination size larger than 16λ (incident wavelength) has good spatial ergodicity. Also, the normalized radar backscattering coefficient for cross polarization of sea surface shows spatial ergodicity when the sea surface size illuminated by radar is not less than one fourth of the largest wind wave length under the corresponding sea conditions. Comparing to the normalized radar scattering coefficient, the spatial ergodicity of monostatic sea clutter amplitude distribution is relatively weaker under the high sea states. With the incident angle increasing, the amplitude distribution of co-polarized sea clutter shows more significant spatial ergodicity, while the cross polarization case is on the opposite.

Key words: ocean radar scattering, spatial ergodicity, sea clutter, Mellin-kind statistics, full-wave numerical simulation

CLC Number: 

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