Sparse Synthetic Aperture Radar Non-Sparse Scene Imaging Method Based on Compressed Sensing
A technology of synthetic aperture radar and compressed sensing, which is applied in the directions of radio wave reflection/re-radiation, utilization of re-radiation, measurement devices, etc., which can solve the problems of inaccurate proof of algorithm convergence, huge amount of data, and high complexity of solving algorithms, etc. problem, to achieve the effect of breaking through the bottleneck of data volume, good noise robustness, and reducing bandwidth requirements
Active Publication Date: 2018-02-27
TSINGHUA UNIV +1
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[0009] Compared with the traditional imaging algorithm, the compressive sensing SAR imaging algorithm in the above article can realize the imaging of non-sparse target scenes while reducing the amount of radar echo data, but the disadvantage lies in the complexity of the algorithm for solving the joint optimization problem Large, and the convergence of the algorithm has not been accurately demonstrated
However, when the actual radar works, the target scene usually does not have good sparsity. For non-sparse scenes, the existing compressed sensing imaging algorithm has problems such as huge data volume and high computational complexity.
The transmission link bandwidth of spaceborne SAR severely restricts the amount of transmitted data, and the existing compressed sensing SAR imaging algorithm is difficult to apply to the non-sparse scene of the actual spaceborne radar system
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[0025] The strip synthetic aperture radar non-sparse scene imaging method based on compressed sensing proposed by the present invention is described as follows in conjunction with the accompanying drawings and embodiments:
[0026] The main process of the inventive method is as figure 1 shown, including the following steps:
[0027] Step 1: The analog / digital conversion module on the satellite samples the radar received analog signal at the Nyquist sampling rate to obtain the original echo complex data matrix X 0 , matrix X 0 The horizontal direction represents the azimuth direction, and the vertical direction represents the distance direction;
[0028] Step 2: Randomly downsample the echo complex data in step 1, and construct the imaging matrix Ψ of the range Doppler algorithm to obtain the observed value of the scene amplitude image;
[0029] Assuming that the radar is looking sideways, the imaged target scene is composed of L×L discrete space lattices, where L is a posit...
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The invention relates to a strip-map synthetic aperture radar non-sparse scene imaging method based on compressed sensing and belongs to the technical field of radar imaging. The method comprises the steps that: an analog / digital conversion module on a satellite samples radar receiving analog signals at a Nyquist sampling rate, and an original echo complex number data matrix is obtained; downsampling is carried out on echo complex number data randomly, an imaging matrix of a distance doppler algorithm is constructed, and an observed value of a scene amplitude image is obtained; a sparse reconstruction model of compressed sensing is established, and the observed value of the scene amplitude image is utilized to recover a discrete cosine transform coefficient of a target scene amplitude image; and two-dimensional discrete cosine inverse transformation is carried out on the reconstructed coefficient, and an amplitude image of a target scene is obtained. The method is used for a non-sparse scene, and the scene amplitude image with a relatively high resolution is reconstructed by means of a small number of observed values, the compressed sensing model and an L1 norm convex optimization means.
Description
technical field [0001] The invention belongs to the technical field of radar imaging, and in particular relates to a non-sparse scene imaging method for a strip-type spaceborne synthetic aperture radar based on range Doppler compressed sensing. Background technique [0002] Synthetic Aperture Radar (SAR, Synthetic Aperture Radar) is a high-resolution imaging radar that can actively observe targets in all-weather, all-weather, large areas, and high-resolution, without being affected by weather, light, climate and other conditions. It has been widely used in the field of radar imaging. SAR obtains high resolution by transmitting large-bandwidth signals in the distance direction, and relies on the motion of the radar platform to form a long synthetic aperture to obtain high resolution in the azimuth direction. Due to the superiority of SAR in the field of radar imaging, the research of SAR imaging algorithm has always been a hot spot. [0003] The traditional strip-type space...
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IPC IPC(8): G01S13/90
CPCG01S13/904G01S13/9054
Inventor 李刚杨晓宇张庆军唐志华
Owner TSINGHUA UNIV