Second Time Integral of the Impulse Response for Enhancing the Late-Time Target Response for Target Identification
A general problem, concerning target identification via the late-time aspectindependent complex natural resonant frequencies, is the presence of the large early-time response. It would be advantageous to enhance the late-time response relative to the early-time response. In a general sense this implies some kind of frequency-dependent filter which attenuates the high-frequency parts of the waveform while providing little or no attenuation to the complex resonant frequencies of interest. Such a low-pass filter (passive and/or active) is the subject of this paper.
A desirable feature of such a filter is the temporal separation of early and latetime responses. Furthermore we would like to be able to still use time gating (windowing) to remove some of the clutter in the signal returned to the radar. So we do not wish to introduce significant dispersion into the scattering data
There are other problems associated with the signal including the response(s) of the radar antenna(s) and propagation characteristics (e.g., multipath). For present purposes we neglect such problems and assume that appropriate deconvolution, gating, etc., have been applied to give the target delta-function response.
KeywordsInput Impedance Target Identification Matrix Pencil Time Gating Surface Current Density
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