Stable and efficient automatic focusing method for decomposition projection

Abstract

The invention discloses an automatic focusing method for decomposition projection. The method comprises the steps: obtaining original data in the whole synthetic aperture time, and dividing the original data into N sub-aperture data; performing focusing imaging processing on each sub-aperture data to obtain a first sub-image; registering the first sub-image in a ground virtual polar coordinate system to obtain registered image data; and performing error correction and sub-image fusion on the registered image data by adopting a fast coordinate descent method to obtain second sub-image data, andoutputting a focusing imaging result if the second sub-image data is a sub-image. According to the invention, the PGA algorithm is applied to the ground virtual polar coordinate system, so that the problem that a traditional frequency domain method is incompatible with a time domain method is solved, automatic focusing in the FFBP algorithm is achieved, and the focusing precision of the sub-aperture images is effectively improved; and the residual phase error model of the sub-images is established, the method is suitable for an unstable strip mode of a radar platform, the error estimation precision is improved, and the calculation complexity is reduced.

Description

technical field [0001] The present invention relates to the technical field of signal processing, in particular to a robust and efficient decomposition and projection automatic focusing method, which is suitable for focus imaging processing of data acquired by SAR platforms such as helicopters and airships with inconstant speeds and irregular trajectories. Background technique [0002] Spaceborne Synthetic Aperture Radar (SAR) is one of the fastest-growing and most effective sensors in microwave remote sensing equipment, and as an active sensor, it is not limited by illumination and weather conditions, and can realize all-weather and all-weather earth observation. [0003] So far, the back-projection algorithm (BP algorithm) is the most common SAR imaging algorithm for obtaining focused SAR images. This is a time-domain algorithm, which can be applied to various SAR systems with different wavelengths, bandwidths and working modes. However, the traditional BP algorithm canno...

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Problems solved by technology

[0005] The purpose of the present invention is to propose a robust and efficient decomposition projection auto-focusing method to solve the problems of high computational complexity, large calibration image deformation error, and low phase error estimation accuracy of existing algorithms, and the algorithm provided by this application improves The focus effect of the algorithm is improved, and a higher quality image can be obtained

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