Engineering Commons^™

Sar-Based Vibration Estimation Using The Discrete Fractional Fourier Transform, Qi Wang, Matthew Pepin, Ryan J. Beach, Ralf Dunkel, Tom Atwood, Balu Santhanam, Walter Gerstle, Armin W. Doerry, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

A vibration estimation method for synthetic aperture radar (SAR) is presented based on a novel application of the discrete fractional Fourier transform (DFRFT). Small vibrations of ground targets introduce phase modulation in the SAR returned signals. With standard preprocessing of the returned signals, followed by the application of the DFRFT, the time-varying accelerations, frequencies, and displacements associated with vibrating objects can be extracted by successively estimating the quasi-instantaneous chirp rate in the phase-modulated signal in each subaperture. The performance of the proposed method is investigated quantitatively, and the measurable vibration frequencies and displacements are determined. Simulation results show that the …