Space target high resolution imaging method based on high resolution range profile (HRRP) sequence

Abstract

The invention discloses a HRRP sequence-based high-resolution imaging method for space targets, the steps of which include: (1) collecting ISAR echoes by radar; (2) high-speed motion compensation; (3) obtaining high-quality HRRP; (4) scattering points Track correlation; (5) High-resolution imaging. The invention first obtains a high-quality HRRP sequence through sparse signal reconstruction, and then uses an effective track correlation method to generate a scattering point track matrix from the HRRP sequence, and then realizes high-resolution imaging through matrix decomposition with constraints. This method overcomes the shortcomings of the segmented pseudo-Keystone transform method, which requires high PRF, strict requirements on the target motion model, high difficulty in accurate translation compensation and initial phase correction, and high computational complexity when imaging high-speed rotating targets. It can perform high-resolution imaging under the condition of azimuth Doppler ambiguity, has universal applicability to the target motion model, does not need translation compensation, high efficiency, and good image focus.

Description

technical field [0001] The invention belongs to the technical field of signal processing, and further relates to a high-resolution imaging method for space targets based on a high-resolution range profile (high-resolution range profiles, HRRP) sequence in the field of radar imaging. The present invention can effectively perform high-resolution imaging on space targets under the condition of low repetition frequency, avoids the influence of azimuth undersampling, translational motion and random initial phase errors on image quality, and provides a strong guarantee for subsequent target recognition. Background technique [0002] In order to obtain a finer and more accurate description of the distribution characteristics of space target scattering points, the requirements for the resolution of radar images are constantly increasing. Among them, the high resolution in the range direction is obtained by transmitting a large time-width-bandwidth product signal; while the high reso...

AI Technical Summary

Problems solved by technology

However, while obtaining high resolution in the range direction, if the traditional imaging method is still used to obtain high resolution in the azimuth direction, new problems will be encountered: First, the improvement of the range resolution will make it easier for the scattering points to move beyond the distance unit , thus limiting the application of imaging methods such as distance-instantaneous Doppler and time-frequency analysis; secondly, because electromagnetic waves are affected by atmospheric disturbances, the echo phase will contain time-varying random initial phase errors

However, the shortcomings of this method are that when the traditional adjacent correlation translation compensation method fails due to the serious movement of the scattering point over the distance unit, the effective translation compensation method is not considered; when the target has variable acceleration rotation, or the radar When performing repetition frequency dithering (that is, pulse repetition frequency changes with time) to realize ECCM (electronic counter-countermeasures), the sinusoidal model assumed by this method is no longer satisfied, resulting in blurred images; at least one rotation period of the target needs to be received Only echoes can get low sidelobe and well-focused images. When the number of echoes is small, the sidelobes are high; the computational complexity is high

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