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Geosynchronous Orbit SAR Imaging Method Based on Singular Value Decomposition

A technology of geosynchronous orbit and singular value decomposition, which is applied in the directions of radio wave reflection/reradiation, utilization of reradiation, measurement devices, etc., can solve problems such as long synthetic aperture time, abnormal azimuth space variation, and wide scene

Active Publication Date: 2017-11-03
XIDIAN UNIV +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the synthetic aperture time of geosynchronous orbit SAR is long, the scene is wide, and the azimuth space variation is extremely serious. It is impossible to directly obtain geosynchronous orbit SAR images with good imaging quality by using spectral analysis algorithms.

Method used

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  • Geosynchronous Orbit SAR Imaging Method Based on Singular Value Decomposition
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  • Geosynchronous Orbit SAR Imaging Method Based on Singular Value Decomposition

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Embodiment Construction

[0024] refer to figure 1 , the geosynchronous orbit SAR imaging method based on singular value decomposition of the present invention comprises the following steps:

[0025] Step 1, the geosynchronous orbit SAR transmits a frequency-modulated pulse signal, and demodulates the received target echo signal to obtain a demodulated echo signal s(t r ,t a )for

[0026]

[0027] where, t r is the distance time, t a is the azimuth time, a r ( ) is the distance envelope function, γ is the modulation frequency of the FM signal, c is the speed of light, a a ( ) is the azimuth envelope function, λ is the wavelength; R(t a ) is the slant distance history of the satellite from the target, and R(t is calculated by the known satellite orbit data a ) is constructed as a quartic polynomial slope distance model, then R 0 is the nearest slope distance, k 1 , k 2 , k3 , k 4 coefficients for the polynomial fit.

[0028] Step 2, use the series inversion method to obtain the demodula...

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Abstract

The invention discloses a geosynchronous orbit SAR imaging method based on singular value decomposition. The method is characterized in that the method comprises the following steps: 1) a geostationary orbit satellite SAR sending a frequency modulation pulse signal, and carrying out demodulation processing on received target echo signals to obtain echo signals s(tr, ta) obtained after demodulation; 2) obtaining two-dimensional frequency spectrum S(fa; fr) of the echo signals obtained after demodulation by utilizing a series inversion method, and carrying out distance pulse pressure processing on the two-dimensional frequency spectrum to obtain phase phi (fr,fa;X,R0) of the two-dimensional frequency spectrum of the echo signals obtained after distance pulse pressure; 3)carrying out decomposition on Doppler frequency and point target azimuth position in the phase phi (fr,fa;X,R0) of the two-dimensional frequency spectrum of the echo signals obtained after distance pulse pressure through singular value decomposition (SVD) to obtain two-dimensional frequency spectrum phase phi (fr,fa;X); 4) carrying out linear interpolation on polynomial v1(fr;fa) in the two-dimensional frequency spectrum phase phi (fr,fa;X) obtained after demodulation to obtain phase phi' (fr,fa' (v1);X) after interpolation; and 5) carrying out phase disturbance processing on the phase phi' (fr,fa' (v1);X) obtained after interpolation, and then, carrying out focusing to obtain a geosynchronous orbit SAR image of a target.

Description

technical field [0001] The invention belongs to the field of radar signal processing, relates to radar imaging technology in a synthetic aperture radar (SAR) system, in particular to geosynchronous orbit SAR imaging, which can be used for SAR imaging processing of airborne or spaceborne platforms. Background technique [0002] Synthetic aperture radar is more and more widely used in earth observation. Spaceborne SAR has been widely studied due to its advantages of all-weather, all-time, high resolution, and wide swath. Most of the SAR satellites currently in operation are low-orbit SAR satellites. Compared with the airborne SAR system, the swath width has been greatly increased, but this is still a certain distance from the actual demand. The geosynchronous orbit SAR satellite has a large swath width and a large beam coverage area. Its orbit height is about 36,000 kilometers. The coverage area of ​​the instantaneous beam can reach hundreds of thousands of square kilometers,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01S13/90
CPCG01S13/904G01S13/9004G01S13/9058
Inventor 孙光才符吉祥张庆君于海峰董祺陈溅来邢孟道
Owner XIDIAN UNIV