Paper
13 December 2024 A THz-ISAR imaging and rotation parameter estimation method for non-uniformly rotating targets based on minimum entropy
Author Affiliations +
Proceedings Volume 13495, AOPC 2024: Terahertz Technology and Applications; 1349507 (2024) https://doi.org/10.1117/12.3046007
Event: Applied Optics and Photonics China 2024 (AOPC2024), 2024, Beijing, China
Abstract
Since there is no atmospheric influence, space-based terahertz inverse synthetic aperture radar (THz-ISAR) can obtain high-resolution images of space targets at a certain distance, so it has important application prospects. In addition, the relative motion of space-based platforms and space targets is complicated. For some satellites that are tumbling out of control or are undergoing attitude change, the imaging angle formed by the target relative to the radar can be considered to be non-uniform, which in turn leads to imaging defocus.In this paper, a minimum entropy-based THz-ISAR rotation parameter estimation and motion compensation method for nonuniformly rotating space targets is proposed. Firstly, the radar echo is compensated for the translational motion and corrected for the range migration to obtain an envelope-aligned one-dimensional range profile. Then, the minimum entropy (ME) algorithm based on Newton’s method (NM) is used to estimate rotational velocity and centre of the targets, and to compensate the range second-order spatial-variant (SV) phase. After that, the golden section method is applied to estimate the target rotational acceleration and compensate the azimuth second-order spatial-variant phase. Finally, the cyclic variable method is used to iterate these two compensation steps alternately to avoid the coupling effect of range and azimuth second-order spatial-variant phase, while obtaining the target rotation parameters and the well-focused imaging results.
(2024) Published by SPIE. Downloading of the abstract is permitted for personal use only.
Liu Wei, Qi Yang, Bin Tang, Zhian Yuan, Bin Deng, and Hongqiang Wang "A THz-ISAR imaging and rotation parameter estimation method for non-uniformly rotating targets based on minimum entropy", Proc. SPIE 13495, AOPC 2024: Terahertz Technology and Applications, 1349507 (13 December 2024); https://doi.org/10.1117/12.3046007
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KEYWORDS
Detection and tracking algorithms

Radar

Radar imaging

Error analysis

Image quality

Satellites

Matrices

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