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SA-ISAR self-focusing method based on joint constraints of structural sparsity and entropy

A self-focusing and sparse technology, applied in the direction of radio wave reflection/re-radiation, instruments, measuring devices, etc., can solve the problems of ISAR self-focusing performance degradation, ISAR image quality degradation, and difficulty in meeting actual engineering needs, etc., to achieve good images Focusing effect, improving self-focusing accuracy, and fast iterative convergence

Active Publication Date: 2021-05-25
NAT UNIV OF DEFENSE TECH
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Problems solved by technology

[0005] The technical problem to be solved by the present invention is that under the condition of sparse aperture, the ISAR self-focusing performance decreases, resulting in the degradation of ISAR image quality, which is difficult to meet the actual needs of the project

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  • SA-ISAR self-focusing method based on joint constraints of structural sparsity and entropy
  • SA-ISAR self-focusing method based on joint constraints of structural sparsity and entropy
  • SA-ISAR self-focusing method based on joint constraints of structural sparsity and entropy

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Embodiment Construction

[0131] The present invention will be further described below in conjunction with accompanying drawing:

[0132] figure 1 Schematic diagram of the structured hierarchical sparse prior model for ISAR images in S2. X in the figure represents the ISAR image, α and γ represent high-level variables, x represents the ISAR image after vectorization expansion, and y represents the vectorization expansion of the sparse aperture echo after envelope alignment. The solid arrows in the figure represent the dependence of the probability distribution between variables, and the "Convolutional Connected" between α and γ represents α m,n The distribution of depends on γ m+1,n+1 And several adjacent elements, "Pointwise Connected" between X and α represents X m,n The distribution of depends on α m,n , "Full Connected" between y and x represents y i The distribution of depends on all elements of x, and the dotted arrow labeled "Vectorize" between x and X does not represent the depen...

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Abstract

The invention belongs to the field of radar signal processing, and specifically relates to a SA-ISAR self-focusing method based on joint constraints of structure sparsity and entropy, comprising the following steps: S1: performing echo modeling on radar echoes after envelope alignment; S2: Apply a hierarchical structured sparse prior to the ISAR image; S3: update the ISAR image and high-level variables through a relaxed variational Bayesian method; S4: update the phase error through a fixed point-based minimum entropy method; S5: Judging whether the termination condition is reached, if the termination condition is reached, the iterative cycle is stopped, otherwise, return to S3, and the self-focused image is output until the termination condition is reached. The present invention can improve the self-focusing precision of the ISAR image under the sparse aperture, so that the formed ISAR image is clearer; the present invention has low computational complexity, fast iterative convergence speed, and strong ability to resist the sparse aperture.

Description

technical field [0001] The invention belongs to the field of radar signal processing, and in particular relates to a sparse aperture inverse synthetic aperture radar (Sparse Aperture-Inverse Synthetic Aperture Radar, SA-ISAR) self-focusing method based on joint constraints of structure sparsity and entropy. Background technique [0002] Imaging technology can obtain high-resolution two-dimensional images of moving targets, thereby capturing the target's two-dimensional size and structural features. It is an important technical means for space target recognition. widely used. [0003] In the field of radar imaging, a signal with a complete pulse in the imaging interval is called a full-aperture signal, and if the echo signal has random or segmented pulses missing, it is called a sparse aperture (SA) signal, and ISAR imaging under a sparse aperture is referred to as SA-ISAR. In the ISAR system, many factors can cause the echo signal aperture to be sparse: First, the low sign...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01S13/90
Inventor 张双辉张弛刘永祥黎湘霍凯姜卫东高勋章
Owner NAT UNIV OF DEFENSE TECH
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