A super-resolution imaging method for oblique forward-looking airborne radar

Abstract

The invention discloses an airborne radar oblique forward-looking super-resolution imaging method, which is applied in the field of radar imaging. In order to solve the problem of low resolution of the traditional oblique forward-looking Doppler sharpening method, the invention establishes The class product accurate echo model breaks through the mechanism bottleneck of improving the resolution of the oblique front viewing angle; then the radar echo is processed by frequency-domain nonlinear projection to remove space variation, and the distance-Doppler strong coupling relationship in the large-width imaging mode is removed; Finally, the high-efficiency super-resolution reconstruction of the scattering coefficient of the target in the oblique front-sight area is realized through the convolution-like merge inversion method. Compared with the traditional DBS method, the invention not only has higher resolution, but also can significantly reduce the computational complexity in the large-width imaging mode, and is suitable for engineering realization.

Description

technical field [0001] The invention belongs to the field of radar imaging, in particular to a large-width and high-resolution imaging technology suitable for oblique front-sight of airborne radar. Background technique [0002] The oblique front-sight of airborne radar refers to the acquisition of target distribution information in the oblique front-sight area of ​​the radar platform. Research on the oblique front-looking high-resolution imaging method of moving platform radar is beneficial to the airborne platform radar system's detection and identification of oblique front terrain, and enhances the reconnaissance, positioning and tracking capabilities of the airborne platform; for the moving radar platform to achieve autonomous landing, terrain Areas such as evasion, material airdrops, and even precision guidance are significant. [0003] At present, the Doppler beam sharpening (Doppler Beam Sharpening) method is mainly used in the oblique forward-looking ground imaging o...

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Problems solved by technology

[0003] At present, the Doppler beam sharpening (Doppler Beam Sharpening) method is mainly used in the oblique forward-looking ground imaging of airborne radar. Although this method has the characteristics of wide imaging angle and good real-time In this mode, the beam sharpening ability drops sharply, which cannot meet the actual imaging resolution requirements

[0004] In order to further improve the resolution of airborne radar oblique forward-looking imaging, the literature "Qi, L., Zheng, M., Yu, W., Li, N. and Hou, L., 2016. Super-resolution Doppler beam sharpening imaging based onan iterative adaptive approach. Remote Sensing Letters, 7(3), pp.259-268." proposed a DBS super-resolution imaging method based on iterative weighted least squares estimation, which can improve the resolution of DBS imaging, but the The method requires operations such as matrix multiplication and matrix inversion, which has high computational complexity and is not suitable for engineering implementation; the literature "Chen H, Li M, Wang Z, et al. Cross-Range Resolution Enhancement for DBS Imaging in aScan Mode Using Aperture-Extrapolated Sparse Representation[J].IEEEGeoscience and Remote Sensing Letters,2017:1-5.", proposed a DBS super-resolution method for extrapolating aperture sparse representation (AESR), using the coherence and Doppler of the azimuth echo The sparsity of the domain DBS image improves the angular resolution of the traditional DBS method, but this method needs to manually adjust the regularization parameters, which cannot meet the adaptive signal processing requirements in practical engineering applications

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