Micro-Doppler analysis in ISAR - review and perspectives

Micro-Doppler analysis concerns the extraction and exploitation of time-varying Doppler frequency shifts produced by mechanical oscillations of a target or target components. Examples of oscillatory motion include mechanical displacements or vibrations of target surfaces, rotations of target components, target spin, precession, or nutation. Such periodic motion modulates the Doppler frequency shift produced by translational motion and manifests itself as localized and time-varying Doppler frequency sidebands. In this paper, we will discuss methods for analyzing, visualizing, and exploiting these micro-Doppler signatures, and present examples of micro-Doppler signatures resulting from both rigid and nonrigid body micro-motion. Appropriate physical motion models will be described and applied to computational electromagnetic tools that generate simulated radar backscattering. Joint time-frequency signal representations will be used to visualize these signatures. We will also discuss challenges, research efforts and our perspectives on the utility of radar micro- Doppler exploitation.