Affiliation:
1. College of Electronic Science, National University of Defense Technology, Changsha 410073, China
Abstract
In recent years, terahertz (THz) radar has been widely researched for its high-resolution imaging. However, the traditional inverse synthetic aperture radar (ISAR) imaging algorithms in the microwave band perform unsatisfactorily in the THz band. Firstly, due to THz radar’s large bandwidth and short wavelength, the rotation of the target will result in serious space-varying(SV) range migration and space-varying phase error. Furthermore, it is challenging to accurately estimate the rotational velocity and compensate for phase errors in the presence of severe range migration effects. Therefore, in this paper, a high-precision THz-ISAR imaging algorithm is proposed. The algorithm includes the following step: First, the SV first-order range migration(FRM) is corrected using keystone transform (KT); then, the minimum entropy based on modified newton (ME-MN) is used to estimate the rotational velocity roughly, and the remaining SV second-order range migration(SRM) is corrected to obtain the range profile with the envelope alignment. Finally, the echo after the envelope alignment is processed for the second time based on ME-MN. The target rotation velocity is accurately estimated, and the phase error is compensated to obtain a well-focused imaging result. The validity of the proposed method is verified by numerical simulation and electromagnetic calculation data.
Funder
National Key R&D Program of China
National Natural Science Foundation of China
Subject
General Earth and Planetary Sciences
Reference24 articles.
1. Ultrawideband ISAR Imaging of Maneuvering Targets With Joint High-Order Motion Compensation and Azimuth Scaling;Shao;IEEE Trans. Geosci. Remote Sens.,2022
2. Range-Doppler Imaging of Rotating Objects;Walker;IEEE Trans. Aerosp. Electron. Syst.,1980
3. A High-Precision Method of Phase-Derived Velocity Measurement and Its Application in Motion Compensation of ISAR Imaging;Fan;IEEE Trans. Geosci. Remote Sens.,2018
4. A High-Resolution 220-GHz Ultra-Wideband Fully Integrated ISAR Imaging System;Mostajeran;IEEE Trans. Microw. Theory Tech.,2019
5. Zhang, Y., Yang, Q., Deng, B., Qin, Y., and Wang, H. (2019). Experimental Research on Interferometric Inverse Synthetic Aperture Radar Imaging with Multi-Channel Terahertz Radar System. Sensors, 19.