Sparse aperture ISAR (Inverse Synthetic Aperture Radar) imaging phase self-focusing method based on image quality guidance

Abstract

The invention relates to an inverse synthetic aperture radar imaging signal processing technology, in particular to a sparse aperture ISAR imaging phase self-focusing method based on image quality guidance. The method comprises the following steps of: S1, constructing a sparse aperture phase self-focusing model based on compressed sensing; S2, selecting a target distance unit that participates inphase estimation parameter estimation; S3, setting an initial parameter value of an iterative algorithm; S4, estimating and compensating a single wheel phase error; S5, determining an iteration termination condition; and S6, updating the phase self-focusing, and reconstructing an ISAR image. According to the sparse aperture ISAR imaging phase self-focusing method based on the image quality guidance, the ISAR imaging phase self-focusing, the ISAR image reconstruction, and the image quality evaluation under the sparse aperture are combined, and four steps of phase error estimation, compensation,reconstruction, and evaluation are realized, the robustness of the algorithm and the accuracy of the phase compensation are improved , and a target ISAR image with higher compensation accuracy and better focusing performance is obtained by reducing the iterative phase error, estimating offset, improving compensation accuracy step by step.

Description

technical field [0001] The invention relates to an inverse synthetic aperture radar (Inverse Synthetic Aperture Radar, ISAR) imaging signal processing technology, in particular to a sparse aperture ISAR imaging phase self-focusing method guided by image quality. Background technique [0002] Traditional ISAR imaging technology requires that the observation target must rotate at a constant speed around a fixed center of rotation. However, in practice, in addition to the rotation of the target during the imaging process, there is also a change in the center of the target relative to the center of the radar, that is, the translational component of the target. The purpose of motion compensation is to eliminate the influence of translation, and the moving target is equivalent to an ideal turntable model, and then the imaging algorithm can be used for imaging. Therefore, motion compensation technology is one of the key technologies in ISAR imaging, and the accuracy of motion comp...

AI Technical Summary

Problems solved by technology

However, in the process of collecting ISAR imaging data, some problems will inevitably be encountered, such as: some echo data are not collected or stored during the observation period due to the radar system itself; Part of the echo data is damaged or missing; when the radar is searching and tracking, different pulse repetition frequencies are used alternately, resulting in non-equal interval distribution of azimuth pulses, etc.

These will lead to problems such as partial unavailability of echo data and damage to data integrity, resulting in echo data under sparse apertures.

The problems caused by sparse aperture echo data to phase compensation mainly include: the abnormal phase change law caused by uneven pulse repetition interval, and the lack of information caused by sparse pulses increases the difficulty of error estimation and phase compensation

There is no effective method for ISAR imaging phase self-focusing algorithm for echo data under sparse aperture

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