Fraunhofer Institute for High Frequency Physics and Radar Techniques FHRWith our radar sensor technology, even the smallest movements of the thorax can be detected and used to analyse respiration and heartbeat. Our solutions show strong potential both in healthcare-related scenarios and as a component of future autonomous mobility systems. A particular advantage lies in the non‑invasive and privacy‑preserving monitoring approach, which operates without camera‑based imaging. Vital‑parameter detection also plays an important role in the rescue of buried or missing persons.
Patient Monitoring
A small device mounted in the upper corner of the room is all that is needed to monitor a multi‑bed hospital ward. Installed unobtrusively near the ceiling, our multi‑channel MIMO sensor—short for Multiple Input Multiple Output—measures the vital parameters of the individuals present in the room, primarily their respiratory rate. Even the heartbeat, a significantly subtler motion, can be detected by the sensor. Because the heart beats at a much higher frequency than the respiratory cycle, the corresponding signals can be clearly separated. With a minimum distance of 60 cm between individuals, the system can even resolve their vital parameters separately—even when the persons are positioned one behind the other from the sensor’s perspective.
The MIMO radar is equipped with eight transmit and eight receive modules. The signals emitted by a transmit module are reflected by various objects (furniture, people, etc.) within the field of view and received by the eight receive modules. Due to their slight spatial separation, the reflected signals reach each module at marginally different times. These differences in propagation time allow conclusions about the spatial position of the corresponding object. The eight transmit modules further increase the achievable spatial resolution.
Beyond vital‑parameter measurement, the radar sensors also enable person tracking, pose estimation, and fall detection, making the sensor solution highly suitable for ambient assisted living systems or applications in assisted‑living environments.
In‑Cabin Monitoring – Radar‑Based Vital Parameter Detection in Vehicles
With our in‑cabin monitoring system, we are developing a radar‑based solution for contactless monitoring of vital parameters inside the vehicle. The sensor technology reliably captures the driver’s respiratory and heart rate, thereby extending future vehicle safety systems with state‑ and attention‑monitoring capabilities.
A particular challenge lies in accurately detecting vital parameters during normal driving conditions. Steering movements, vehicle vibrations, and accelerations during braking or cornering superimpose the subtle motions associated with respiration and heartbeat, complicating the signal analysis.
To address this, we employ advanced radar techniques capable of detecting, tracking, and linking multiple reflections from the person inside the vehicle. This is complemented by intelligent signal‑processing and filtering methods that distinguish between unwanted motion artefacts and genuine vital signs. As a result, respiratory and heart rates can be estimated in real time even during active driving.
Initial results demonstrate stable extraction of respiratory motion despite vehicle and driver movements. Comparative measurements with reference systems show deviations of only about 0.5 breaths per minute for respiratory rate and less than 8 beats per minute for heart rate. With our functional demonstrator, real‑time live estimation can already be demonstrated.
To further improve measurement accuracy, current research at Fraunhofer FHR includes a systematic investigation of different sensor positions within the vehicle interior. Additionally, a KI‑based validity check is employed to detect disturbance motions and exclude erroneous measurements. This combination enables even more robust and reliable contactless vital‑parameter detection under real driving conditions.