Respiration Rate Estimation Using IR-UWB Radar Based on the Second Maximum Eigenvalues

Impulse Radio Ultra-Wide-Band (IR-UWB) radar is a promising technology for contact-less sensing applications, such as Vital Sign (VS) detection of human body. This paper presents a new approach for Respiration Rate (RR) estimation of a stationary person. The particularity of this approach is that does not require any pre-processing techniques. It is based on the estimation of the Second Maximum Eigenvalue (SME) using Singular Value Decomposition (SVD). To extract the VS signal, a packet of eigenvalues is acquired using a moving matrix window over the slow time direction of the radar data. Then applying a Fast Fourier Transform (FFT), the respiration rate can be easily estimated. Experiments are performed using a P440 (IR-UWB) radar. The results are encouraging and show that the proposed method effectively detects the VS with high accuracy even in low Signal to Noise Ratio (SNR) condition, such as in through the wall human detection scenario.