Systems Engineering and Electronics ›› 2023, Vol. 45 ›› Issue (12): 3828-3835.doi: 10.12305/j.issn.1001-506X.2023.12.12

• Sensors and Signal Processing • Previous Articles    

A range-dependent phase gradient autofocus algorithm integrated stochastic sample selection for SAR imaging

Zhichao MENG1, Lei ZHANG1,*, Jingyue LU2, Jun LI3   

  1. 1. School of Electronics and Communication Engineering, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China
    2. School of Computer Science and Technology, Xidian University, Xi'an 710071, China
    3. Beijing Institute of Radio Measurement, Beijing 100854, China
  • Received:2022-06-06 Online:2023-11-25 Published:2023-12-05
  • Contact: Lei ZHANG

Abstract:

Aiming at the sample selection method in the range-dependent phase gradient autofocus (PGA) algorithm, a novel range-dependent PGA (RDPGA) algorithm based on stochastic sample selection is proposed in this paper. Different from the traditional algorithms, in which a fixed threshold is utilized to exclude a part of characteristic point samples, the proposed algorithm uses the samples' signal to clutter ratio (SCR) to construct a probability density function for sample selection. Samples are stochastically selected in each iteration according to the probability density function. Stochastic sample selection ensures the diversity of range cell samples, improving the estimation accuracy of RDPGA. In addition, the probability distribution ensures the high contribution of high-quality samples in the estimation of model parameters. It improves the robustness of convergence while promising a high efficiency. The actual measured data processing results show that the proposed algorithm has high estimation accuracy and robustness.

Key words: autofocus, phase gradient autofocus (PGA), stochastic sample selection

CLC Number: 

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