Radar micro-Doppler signatures of various human activities

This study presents the results of the authors' experimental investigation into the radar micro-Doppler signatures (MDS) of various human activities both in free-space and through-wall environments. The collection of MDS signatures was divided into three categories: stationary, forward-moving, and multi-target. Each category of MDS signatures encompassed a variety of movements associated with it, adding up to a total of 18 human movements. Using a 6.5-GHz C-band coherent radar, the MDS of six human subjects were gathered in free-space and through-wall environments. The MDS for these cases were analysed in detail and the general properties of the signatures were related to their associated phenomenological characteristics. Based upon the MDS, features for designing detectors and classifiers of human targets performing such movements are recommended. In the case of multiple human targets in the radar field of view, it was found that it is possible to distinguish these targets from the MDS under certain circumstances, but not under others.