Method for suppressing two-dimensional side lobes on horizontal planes for geosynchronous orbit circular SAR (synthetic aperture radar)

Abstract

The invention discloses a method for suppressing two-dimensional side lobes on horizontal planes for geosynchronous orbit circular SAR (synthetic aperture radar), and belongs to the field of synthetic aperture radar (SAR) signal processing. The method has the advantages that the method is based on characteristics of geosynchronous orbit circular SAR three-dimensional imaging target response functions, two-dimensional side lobe suppression filter functions can be obtained on the basis of confocal algorithms by the aid of total least squares iterative processes, and accordingly the two-dimensional high side lobes on the horizontal planes can be suppressed for the geosynchronous orbit circular SAR; the two-dimensional horizontal high side lobes can be effectively diminished (peak side lobe ratios can be reduced from the original -7.9 dB to -20 dB approximately, and integration side lobe ratios can be reduced from the original -4.79 dB to -20 dB approximately) for the geosynchronous orbit circular SAR by the aid of the method without loss of resolution, and accordingly the imaging and interference performance of the geosynchronous orbit circular SAR can be improved.

Description

technical field [0001] The invention relates to a sidelobe suppression method of a spaceborne three-dimensional imaging SAR (Synthetic Aperture Radar, synthetic aperture radar) image on a two-dimensional horizontal plane, belonging to the technical field of radar imaging and interference. Background technique [0002] Conventional SAR moves along a straight line trajectory, and obtains two-dimensional high-resolution slant-range images of the observed object along the moving direction of the sensor and the line of sight of the sensor through Doppler beam sharpening and pulse compression. In recent years, anti-terrorism, ground exploration, reconnaissance, medical detection and other fields have put forward the requirements for high-resolution three-dimensional imaging of observation targets. Interferometric SAR (InterferometricSAR, InSAR) performs interferometric processing on the complex images obtained by multiple antenna observations to obtain the elevation information of...

AI Technical Summary

Problems solved by technology

Different from the conventional SAR mode, geosynchronous orbit circular SAR can realize three-dimensional imaging. The two-dimensional impulse response function of the horizontal plane is in the form of a Bessel function, and the x and y dimensions of the horizontal plane are coupled with each other. Therefore, the existing sidelobe suppression technology cannot be directly used on the earth Horizontal High Sidelobe Suppression of Synchronous Orbit Circular SAR

Compared with the sinc function form, the system response function of the zero-order Bessel function form has higher side lobes, which limits the imaging and interference applications of the geosynchronous orbit circular SAR mode. Two-dimensional sidelobe suppression technology is very necessary

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