MuBP: Multimodel and Continuous Blood Pressure Measurement via UWB-IMU Fusion on Commercial Smartwatches

Blood pressure (BP) is a critical indicator for assessing cardiovascular health. However, existing wearable and Radio Frequency (RF)-based methods typically require users to maintain static postures to obtain stable measurements, failing to ensure continuity during daily activities. To address this, we propose MuBP, which achieves continuous BP measurement via multimodal data fusion of Ultra-Wideband (UWB) and Inertial Measurement Unit (IMU) sensors in commercial smartwatches. The MuBP system first extracts Channel Impulse Responses (CIR) from UWB signals and constructs a motion-aware state matrix to effectively separate wrist motion artifacts from pulse signals. Subsequently, a periodic feature extraction network is designed to capture multi-scale pulse waveform features. Finally, a Bidirectional Long Short-Term Memory (Bi-LSTM) network is adopted to model temporal dependencies, combined with attention mechanisms for adaptive feature selection. We implement the MuBP system on a commercial mobile device and conduct 500 experiments involving 50 participants. Extensive results show that MuBP achieves Mean Errors (ME) and Standard Deviations (STD) of 1.86 ± 6.16 mmHg for systolic BP and 1.08 ± 5.6 mmHg for diastolic BP, maintaining stable measurements under diverse factors and complying with the Association for the Advancement of Medical Instrumentation (AAMI) SP10 standard. Additionally, MuBP supports real-time hypertensive risk alerts, providing an efficient solution for continuous non-invasive BP monitoring in daily life.