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SA-ISAR (Sparse Aperture-Inverse Synthetic Aperture Radar) self focusing method based on structure sparsity and entropy joint constraints

A self-focusing and sparse technology, applied in the direction of reflection/re-radiation of radio waves, utilization of re-radiation, measurement devices, etc., can solve problems such as difficulty in meeting actual engineering needs, degradation of ISAR self-focusing performance, and degradation of ISAR image quality.

Active Publication Date: 2020-01-24
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 (Sparse Aperture-Inverse Synthetic Aperture Radar) self focusing method based on structure sparsity and entropy joint constraints
  • SA-ISAR (Sparse Aperture-Inverse Synthetic Aperture Radar) self focusing method based on structure sparsity and entropy joint constraints
  • SA-ISAR (Sparse Aperture-Inverse Synthetic Aperture Radar) self focusing method based on structure sparsity and entropy joint constraints

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[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 particularly relates to an SA-ISAR (Sparse Aperture-Inverse Synthetic Aperture Radar) self focusing method based on structure sparsity and entropy joint constraints. The method comprises the following steps of Step 1, performing echo modeling on radar echo subjected to envelope alignment; Step 2, applying layered structured sparseprior to an ISAR image; Step 3, updating the ISAR image and an upper layer variable by a relax variational bayes method; Step 4, updating a phase error through a minimum entropy method based on fixedpoints; and Step 5, judging whether a termination condition is reached or not, stopping iterative loop if the termination condition is reached, returning to the Step 3 if the termination condition isnot reached, and outputting an image subjected to self focusing after the termination condition is reached. The SA-ISAR self focusing method has the advantages that the self focusing precision of theISAR images at the sparse aperture can be improved, so that the formed ISAR images are clearer; the calculation complexity is lower; the iterative convergence speed is faster; and the sparse apertureresistance capability is high.

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...

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Application Information

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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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