Micro-Doppler Effect Analysis and Feature Extraction in ISAR Imaging With Stepped-Frequency Chirp Signals

• Published in: IEEE transactions on geoscience and remote sensing 2010-04, Vol.48 (4), p.2087-2098
• Main Authors: Luo, Ying, Zhang, Qun, Qiu, Cheng-wei, Liang, Xian-jiao, Li, Kai-ming
• Format: Article
• Language: English
• Subjects: Algorithms; Applied geophysics; Bandwidth; Chirp; Chirp signals; Earth sciences; Earth, ocean, space; Exact sciences and technology; Exact solutions; Extraction; Feature extraction; High-resolution imaging; Hough transform (HT); Hough transforms; Image analysis; Internal geophysics; Inverse synthetic aperture radar; inverse synthetic aperture radar (ISAR); micro-Doppler (m-D) effect; Rotating; Signal analysis; Signal resolution; Signal synthesis; Signatures; stepped-frequency chirp signal (SFCS); Target recognition; time-frequency analysis
• ISSN: 0196-2892; 1558-0644
• DOI: 10.1109/TGRS.2009.2034367

The micro-Doppler (m-D) effect induced by the rotating parts or vibrations of the target provides a new approach for target recognition. To obtain high range resolution for the extraction of the fine m-D signatures of an inverse synthetic aperture radar target, the stepped-frequency chirp signal (SFCS) is used to synthesize the ultrabroad bandwidth and reduce the requirement of sample rates. In this paper, the m-D effect in SFCS is analyzed. The analytical expressions of the m-D signatures, which are extracted by an improved Hough transform method associated with time-frequency analysis, are deduced on the range-slow-time plane. The implementation of the algorithm is presented, particularly in those extreme cases of rotating (vibrating) frequencies and radii. The simulations validate the theoretical formulation and robustness of the proposed m-D extraction method.