
Proceedings Paper
SAR-based vibration retrieval using the fractional Fourier transform in slow timeFormat | Member Price | Non-Member Price |
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Paper Abstract
Recent reports on the effects of vibrating targets on synthetic-aperture radar (SAR) imagery and the potential
of SAR to extract non-stationary signatures have drawn significant interest from the remote-sensing community.
SAR returned signals are the superposition of the transmitted pulses modulated by both static and non-static
targets in both amplitude and phase. More precisely, the vibration of a target causes a small sinusoid-like frequency
modulation along the synthetic aperture (slow time), whereby the phase deviation is proportional to
the displacement of the vibrating object. By looking at successive small segments in slow time, each frequency
modulated pulse can be tracked and further approximated as a piecewise-linear frequency-modulated signal. The
discrete-time fractional Fourier transform (DFRFT) is an analysis tool geared toward such signals containing linear
frequency modulated components. Within each segment, the DFRFT transforms each frequency-modulated
component into a peak in the DFRFT plane, and the peak position corresponds to the frequency modulation rate.
A series of such measurements provides the instantaneous-acceleration history and its spectrum bears the vibrating
signature of the target. Additionally, when the chirp z-transform (CZT) is incorporated into the DFRFT,
vibration-induced modulations can be identified with high resolution. In this work, the interplay amongst SAR
system parameters, vibration parameters, the DFRFT's window size, and the CZT's zoom-in factor is characterized
analytically for the proposed SAR-vibrometry approach. Simulations verify the analysis showing that the
detection of vibration using the slow-time approach has significantly higher fidelity than that of the previously
reported fast-time approach.
Paper Details
Date Published: 27 April 2010
PDF: 10 pages
Proc. SPIE 7669, Radar Sensor Technology XIV, 766911 (27 April 2010); doi: 10.1117/12.849671
Published in SPIE Proceedings Vol. 7669:
Radar Sensor Technology XIV
Kenneth I. Ranney; Armin W. Doerry, Editor(s)
PDF: 10 pages
Proc. SPIE 7669, Radar Sensor Technology XIV, 766911 (27 April 2010); doi: 10.1117/12.849671
Show Author Affiliations
Qi Wang, The Univ. of New Mexico (United States)
Matthew Pepin, The Univ. of New Mexico (United States)
Balu Santhanam, The Univ. of New Mexico (United States)
Matthew Pepin, The Univ. of New Mexico (United States)
Balu Santhanam, The Univ. of New Mexico (United States)
Tom Atwood, Sandia National Labs. (United States)
Majeed M. Hayat, The Univ. of New Mexico (United States)
Majeed M. Hayat, The Univ. of New Mexico (United States)
Published in SPIE Proceedings Vol. 7669:
Radar Sensor Technology XIV
Kenneth I. Ranney; Armin W. Doerry, Editor(s)
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