Micro-Doppler signatures carry distinctive features of movements of human body parts. Based on micro-Doppler signatures, it is possible to identify movement human body parts.

Any SDR kit can be used for human activity data collections. Especially, C-band SDR-KIT 580AD, X-band SDR-KIT 980AD, and K-band SDR-KIT 2400AD are often used for human activity study. With two-channel transmitter and multi-channel receiver SDR-KITs, you can further collect data as bistatic radar, monopulse radar, interferometric radaror polarimetric radar.

Research group in the University of Glasgow, U.K. used Ancortek SDR-KITs for studying micro-Doppler signatures of human activities. From collected radar data, the typical signal processing chain can be range-time waterfall, range-Doppler map, and Doppler-time (micro-Doppler) signature. As illustrated in Figure 1, it shows the corresponding range-time waterfall, range-Doppler map and micro-Doppler signature of a person walking back and forth in front of the radar.

Figure1 – The range-time waterfall, range-Doppler map and micro-Doppler signature of
a person walking back and forth in front of the SDR-KIT.

As an example, Figure2 shows micro-Doppler signatures of 6 different activities recorded by SDR-KIT 580AD. The 6 activities are: (a) Setting on a chair; (b) Standing up from a chair; (c) Bending to tie shoe-laces; (d) Bending to pick up an object; (e) Crouching and standing back up; and (f) Falling frontally after tripping. While the activity movements toward the radar, bending down and falling frontally show positive values, sitting on a chair generates a significant negative value. All these activities generate a significant acceleration and a sudden velocity signature.

Figure2– Micro-Doppler signatures of human activities using anSDRKIT 580AD.

Reference: F. Fioranelli, J. Le Kernec, and S. Aziz Shah, “Radar for health care: Recognizing human activities and monitoring vital signs,” IEEE Potentials 2019, 38(4), pp.18-23.

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