Doppler Radar for the Extraction of Biomechanical Parameters in Gait Analysis

Area of Science:

• Biomechanics
• Medical sensor technology
• Signal processing

Background:

• Gait analysis is crucial for diagnosing and managing various medical conditions.
• Traditional gait analysis methods (motion capture, force plates) can be cumbersome, expensive, and intrusive.
• There is a need for non-contact, privacy-preserving, and accessible gait analysis solutions.

Purpose of the Study:

• To investigate the applicability of Doppler radar for quantitative gait analysis.
• To compare radar-derived biomechanical parameters with those from motion capture and ground reaction forces.
• To introduce novel radar-based methods for extracting gait parameters, including joint velocities and leg flight times.

Main Methods:

• Nineteen participants walked on a treadmill at two speeds with a radar system positioned front or back.
• A knee orthosis was used to vary knee angle in five configurations.
• Gait parameters were extracted from radar micro-Doppler signatures, with new methods for joint velocities and flight times proposed.

Main Results:

• Five spatiotemporal gait parameters (rhythm, pace) were reliably extracted from radar data.
• Three kinematic parameters were accurately measured under most conditions.
• Radar-based stance and flight times were accurate when the radar had a rear view, but underestimated when front-facing.

Conclusions:

• Doppler radar is a validated technology for accurately measuring medically relevant gait parameters.
• Radar offers potential for unobtrusive gait change diagnosis, aiding in rehabilitation and prevention.
• As a contact-less and privacy-preserving sensor, radar can supplement existing tools for long-term home-based gait monitoring.