Bistatic SAR two-dimensional self-focusing method based on prior phase structure information

Abstract

The invention discloses a bistatic SAR (Synthetic Aperture Radar) two-dimensional self-focusing method based on prior phase structure information. With new interpretation of the bistatic SAR polar format algorithm (PFA), the mechanism of the bistatic PFA algorithm on the two-dimensional phase error is analyzed in detail, and the analytical structure of the residual two-dimensional phase error is obtained. On the basis of the prior phase structure information, dimension reduction processing is performed, a bistatic SAR two-dimensional self-focusing method combining prior information and complete echo data is provided. According to the method, firstly, priori knowledge is introduced, and two-dimensional phase error estimation is subjected to dimensionality reduction to form one-dimensional azimuth phase error estimation; and the residual one-dimensional azimuth phase error in the PFA image is estimated through a multi-sub-band data averaging method; and finally, the one-dimensional azimuth phase error is mapped to obtain a two-dimensional phase error by applying a frequency modulation variable-scale principle, thereby completing compensation of the two-dimensional phase error. The method can greatly reduce the calculation amount of the algorithm and improve the parameter estimation precision at the same time.

Description

technical field [0001] The invention relates to a bistatic SAR two-dimensional self-focusing algorithm based on prior phase structure information, and belongs to the technical field of radar imaging. Background technique [0002] Synthetic Aperture Radar (SAR) is a high-resolution radar system that uses small-aperture radar motion and coherently processes radar echoes at different positions to generate high-resolution scene images. Usually traditional SAR refers to monostatic synthetic aperture SAR, that is, the radar transmitting antenna and receiving antenna are located on the same platform. But in recent years, with the maturity of technology, Bistatic Synthetic Aperture Radar (Bistatic SAR) has become a research hotspot. Compared with single-base SAR, bi-base SAR has the advantages of flexible configuration, rich information acquisition, high concealment, and strong anti-interference due to the characteristics of separate transceivers. However, the complex imaging geom...

AI Technical Summary

Problems solved by technology

These existing methods either only consider the estimation and compensation of the one-dimensional azimuth phase error, and it is difficult to meet the precise focusing requirements under the condition of ultra-high resolution or low motion sensor accuracy; or although the two-dimensional phase error is considered, the The estimation of range direction and azimuth direction is carried out independently, and the inherent structure of the two-dimensional phase error is not fully utilized. There are problems of large amount of calculation and insufficient estimation accuracy. Therefore, these methods still have certain limitations in practical applications.

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