Signal processing method of satellite-bone sliding spotlight synthetic aperture radar

Abstract

The invention discloses a signal processing method of a satellite-bone sliding spotlight synthetic aperture radar. The method includes: performing molecule aperture processing on original echo data of the sliding spotlight synthetic aperture radar (SAR); performing range compression and range migration correction through a chirp scaling (CS) algorithm; introducing squint angle compensation in theCS algorithm; compensating scene space-variant performance; adjusting range migration amount of all sub-apertures to be identical with Doppler parameters of full apertures in CS scalar variable factors as the standard; performing azimuth compression and quadratic term compensation in the frequency domain, and performing frequency modulation processing in the time domain; splicing data of all the sub-apertures and restoring resolution ratio of the full apertures; and enabling signals to have phase preservation performance through spectrum analyzer (SPECAN) processing. By adopting the signal processing method, imaging quality can be improved under the condition of large scene squinting.

Description

technical field [0001] The invention relates to a method for processing synthetic aperture radar signals, in particular to a signal processing method under the condition of squinting in a large scene in a sliding spotlight mode. Background technique [0002] Synthetic Aperture Radar (SAR) is a typical radar system for ground reconnaissance and imaging. It is mainly used for military reconnaissance and disaster monitoring. It is currently one of the important microwave remote sensing instruments that can work all day and all day. At present, the common working modes of SAR mainly include strip mode, scanning mode, spotlight mode, sliding spotlight mode, TOPS mode and so on. Among these SAR imaging modes, the strip mode can achieve a wide swath in azimuth, but it is difficult to achieve high resolution; in the scan mode, although a swath with a wide range and azimuth can be obtained at the same time, the resolution is sacrificed. At the cost, its resolution is lower than that...

AI Technical Summary

Problems solved by technology

The existence of oblique angle of view will cause the loss of signal-to-noise ratio during radar imaging, the decrease of azimuth ambiguity, and the image shift

In addition, spaceborne synthetic aperture radar beams illuminate a large range, especially in high-resolution imaging, where the spatial variability of the scene cannot be ignored

The existing sliding beam spotlight SAR imaging algorithm does not take into account the situation under the oblique angle of view, nor does it consider the compensation of the spatial variability of the scene in the case of a large scene, and does not perform consistent compensation for the phase of each sub-aperture (in multiple sub-apertures The image quality will be affected when the final stitching is performed), the above three aspects will affect the image quality

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