Analysis of Micro-Doppler Signatures for Radar
Abstract: When radar transmits an electromagnetic signal to a target, the signal interacts with the target and returns back to the radar. The change in the properties of the returned signal reflects characteristics of interest in the target. When the target is moving, the carrier frequency of the returned signal will be shifted, known as the Doppler effect. The Doppler frequency shift determines the radial velocity of the moving target. If the target or any structure on the target has mechanical vibration or rotation in addition to the target translation, it may induce frequency modulation on the returned signal that generates side-bands about the target’s Doppler frequency shift. This is called the micro-Doppler phenomenon. Micro-Doppler effect enables us to determine some properties of the target. For example, vibrations generated by a vehicle engine may be detected from the surface vibration of the vehicle. From the micro-Doppler signature of engine vibration signals, we could further distinguish a gas turbine engine of a tank from a diesel engine of a bus. The micro-Doppler effect can be used to identify specific types of vehicles and determine their movement and speed of their engines.
We discuss micro-Doppler effects in microwave radar, derive theoretical results for micro-Doppler induced by vibrations and rotations, and introduce the time-frequency analysis of micro-Doppler phenomena. We simulate radar returns from targets undergoing accelerations, vibrations or rotations, compare simulation results with theoretical results and confirm the effectiveness of our theory. To verify micro-Doppler effects in microwave radar, we demonstrate examples using measured radar data to extract micro-Doppler signatures and obtain information about target’s micro-motion dynamics.
References:
V.C. Chen, F. Li, S.-S. Ho and H. Wechsler, Micro-Doppler effect in radar - Phenomenon , Model, and Simulation Study, IEEE Transactions on Aerospace and Electronic Systems, vol. 42, no. 1, 2006, pp 2-21.
V.C. Chen, F. Li, S.-S. Ho and H. Wechsler, Analysis of micro-Doppler signatures, IEE Proc.-Radar Sonar Navig., Vol. 150, No. 4, 2003, pp 271-276.