Limitations and capabilities of the slanted spectrogram analysis tool for SAR-based detection of multiple vibrating targets

The recently developed improved spectrograms that use the discrete fractional fourier transform (DFrFT) are used to evaluate multiple vibration signatures that represent targets in synthetic aperture radar (SAR) data. Multiple ground target vibrations that introduce phase modulation in the SAR returned signals are examined using standard pre-processing of the return waveform signal followed by the application of the DFrFT. In this paper, we study the capabilities of these spectrogram tools with the intent of extending their limits by varying the characteristic features associated with each vibrating target which result in different outputs. The performance of the fractional spectrogram tools, under the effects of various parameters is used to clarify the limitations and advantages of these modified fractional spectrograms for SAR-based vibrometry applications.