Multiple Object Localization and Vital Sign Monitoring Using IR-UWB MIMO Radar

We consider 2-D localization and noncontact vital sign monitoring (i.e., determining the 2-D locations and estimating the rates of respiration and heartbeat) of multiple human objects via developing an impulse radio ultra-wideband (IR-UWB) distributed multi-input multi-output (MIMO) prototype radar system. A modified back projection algorithm is used to localize multiple objects. We also formulate the chest skin range displacement estimation problem caused by respiration and heartbeat into a sinusoidal frequency estimation problem, which can be solved efficiently via the fast Fourier transform method. Then, the robust, high resolution, and low sidelobe iterative adaptive approach (IAA) is adopted to obtain the IAA spectrum of the chest skin range displacement signal. Both respiration and heartbeat rates can be reliably determined from the IAA spectral estimates. Further, we solve the random body movement problem by developing a 2 × 2 IR-UWB distributed MIMO prototype radar system to obtain measurements from both the front and back of the human torso simultaneously. Finally, numerical and experimental results based on the prototype hardware radar systems we develop are presented to demonstrate the performances of the proposed 2-D localization and noncontact vital sign monitoring systems and the corresponding algorithms.