Envelope Correction of Micro-Motion Targets in the Terahertz ISAR Imaging
College of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073, China
Author to whom correspondence should be addressed.
Sensors 2018, 18(1), 228; https://doi.org/10.3390/s18010228
Received: 5 December 2017 / Revised: 6 January 2018 / Accepted: 14 January 2018 / Published: 15 January 2018
(This article belongs to the Special Issue Sensors for Microwave Imaging and Detection)
Motion compensation is a crucial step to inverse synthetic aperture radar imaging, and envelope correction is the foundation of motion compensation. Research on envelope correction based on the small-angle imaging model has matured after years of development. However, the small-angle imaging model is not applicable to parameter estimation and imaging of micro-motion targets. According to the characteristics of the micro-motion targets and the superiorities of terahertz imaging radar, an envelope correction method for micro-motion targets in the terahertz region was proposed in this paper, including the jump error correction based on periodic correction and drift error compensation based on nonlinear fitting. Then a 330 GHz imaging radar and two experiments on corner reflectors and a warhead model were introduced. The validity of the method was verified by the experimental results, and the performance of the method was proved by the inverse Radon transform of the range profile sequences.