Analysis of micro-motion model for radar target

The mechanical dynamics in addition to its bulk translation of the target or any structure on the target is called micro-motion. Micro-motion evokes a frequency modulation in radar echo known as micro-Doppler (m-D) effect which may help to detect specific structures of a target with micro-motion, leading a potential way to realize target identification by extracting the micro-Doppler features. In most literatures, the micro-motions were modeled as the sinusoidal forms. In fact the micro-motions in reality should include more types of movement forms besides the sinusoidal one. This paper derives the foundation of universal micro-motion model for radar target other than the popular sinusoidal model. The mathematical formulas of micro-Doppler induced by targets with arbitrary micro-motion are derived, and some examples of several basic and typical micro-motion types (vibration, rotation, sinusoidal, pendulum) are given. At last the simulation studies based on the point scattering model are conducted to validate the proposed theoretical model.