Improved orthogonal coding method suitable for low-signal-to-noise-ratio wide-swath SAR imaging

An orthogonal coding, low signal-to-noise ratio technology, applied in the field of improved orthogonal coding algorithms, can solve the problem of inability to obtain high-resolution high-signal-to-noise ratio SAR images, etc., and achieve the effect of improving the signal-to-noise ratio

Inactive Publication Date: 2020-01-31
NORTHWESTERN POLYTECHNICAL UNIV
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Problems solved by technology

Direct use of the existing SAR wide swath imaging technology will not be able to obtain SAR images with high resolution and high signal-to-noise ratio

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  • Improved orthogonal coding method suitable for low-signal-to-noise-ratio wide-swath SAR imaging
  • Improved orthogonal coding method suitable for low-signal-to-noise-ratio wide-swath SAR imaging
  • Improved orthogonal coding method suitable for low-signal-to-noise-ratio wide-swath SAR imaging

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Embodiment Construction

[0016] The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

[0017] An improved orthogonal coding algorithm suitable for wide swath SAR imaging with low signal-to-noise ratio includes the following steps:

[0018] Step 1, the encoded waveform transmitted at the ith slow time in azimuth is: where i=1,...,Q, there are Q azimuth slow time instants in total. is the fast time, N is the number of sub-symbols, is the coding frequency of the nth subsymbol at the ith slow time.

[0019] Step 2, Design Amplitude It is a rectangular 2 function and satisfies T sub is the subcode time width.

[0020] Step 3, coding frequency design, coding frequency at the ith slow time instant The choice of is a permutation and combination of {Δf,2Δf,...,(N-1)Δf}, where Δf=1 / T sub , the total bandwidth of the waveform B=NΔf.

[0021] Step 4, orthogonal waveform design, the transmission is multiple sets of orthogonal codes, and i...

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Abstract

The invention relates to an improved orthogonal coding method suitable for low-signal-to-noise-ratio wide-swath SAR imaging. A coding waveform is obtained by designing amplitude and coding frequency,and a waveform suitable for a low signal-to-noise ratio condition is designed according to the coding waveform. The method can obtain an SAR image with high resolution and high signal-to-noise ratio of a marine moving target by combining a compressed sensing technology, and the signal-to-noise ratio is improved.

Description

technical field [0001] The invention belongs to the field of radar system design and signal processing, and in particular relates to an improved orthogonal coding algorithm suitable for wide swath synthetic aperture radar imaging under the condition of low signal-to-noise ratio, and the algorithm is suitable for echo existence in the wide swath mode When the distance is blurred, the compressive sensing algorithm is combined to de-blur the scene. Background technique [0002] Spaceborne SAR is more and more widely used in earth observation. In order to reduce the number of revisits to the ground scene, the width of the observation scene is required to be large. Especially in the monitoring of sea surface targets, because the sea surface is relatively wide and the sea surface targets are relatively sparse, it is difficult to effectively monitor the sea surface targets if the swath is not wide enough. There are many methods to expand the surveying and mapping bandwidth. The ex...

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Application Information

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IPC IPC(8): G01S13/90
CPCG01S13/90G01S13/904
Inventor张双喜熊文俊李少杰吴亿峰刘艳阳
OwnerNORTHWESTERN POLYTECHNICAL UNIV