Characterisation of human gait using a continuous-wave radar at 24 GHz

[摘要] Human locomotion consists of a complex movement of various parts of the body.The reflections generated by body parts with different relative velocitiesresult in different Doppler shifts which can be detected as a superpositionwith a Continuous-Wave (CW) Radar. A time-frequency transform like theshort-time Fourier transform (STFT) of the radar signal allows arepresentation of the signal in both time- and frequency domain(spectrogram). It can be shown that even during one gait cycle the velocityof the torso, which constitutes the major part of the reflection, is notconstant. Further a smaller portion of the signal is reflected from the legs.The velocity of the legs varies in a wide range from zero (foot is on theground) to a velocity which is higher than that of the torso. The twodominant parameters which characterise the human gait are the step rate andthe mean velocity. Both parameters can be deduced from suitable portions ofthe spectrogram. The statistical evaluation of the two parameters has thepotential to be included for discrimination purposes either between differentpersons or between humans and other moving objects.

[学科分类] 电子、光学、磁材料