Non-contact Vital Signs Detection in Dynamic Environments

TL;DR

This paper introduces a new DC offset calibration and demodulation method for millimeter-wave radar vital sign detection, improving robustness and accuracy in complex, noisy environments.

Contribution

It presents a novel calibration and demodulation algorithm that enhances vital sign detection accuracy under dynamic, noisy conditions.

Findings

Maintains robust performance in low SNR environments.

Provides more accurate signal recovery compared to existing methods.

Effectively suppresses noise interference in complex scenarios.

Abstract

Accurate phase demodulation is critical for vital sign detection using millimeter-wave radar. However, in complex environments, time-varying DC offsets and phase imbalances can severely degrade demodulation performance. To address this, we propose a novel DC offset calibration method alongside a Hilbert and Differential Cross-Multiply (HADCM) demodulation algorithm. The approach estimates time-varying DC offsets from neighboring signal peaks and valleys, then employs both differential forms and Hilbert transforms of the I/Q channel signals to extract vital sign information. Simulation and experimental results demonstrate that the proposed method maintains robust performance under low signal-to-noise ratios. Compared to existing demodulation techniques, it offers more accurate signal recovery in challenging scenarios and effectively suppresses noise interference.