Global Navigation Satellite Systems (GNSS), often referred to by the more familiar term GPS (which is just one of such systems), have been in use since the late 20th century.
These carefully designed constellations of satellites continuously broadcast electromagnetic signals, enabling anyone on Earth to determine their precise location. Of course, this is an oversimplification: accurate positioning also requires the ability to receive, process, and compute location data from these signals, which necessitates both an antenna and a receiver.
This elegant and efficient positioning technology quickly caught the attention of the wearable device industry. Wearable devices encompass a wide range of gadgets worn on the body, typically equipped with sensors, processors, and communication capabilities. They are designed to collect, process, and often display real-time data, providing users with valuable insights and enabling specialized functionalities. These devices are widely used in healthcare, fitness, and sports performance. A prime example is the smartwatch, which continuously monitors metrics such as heart rate while seamlessly integrating with smartphones, headphones, and other devices.
Integrating GNSS into wearables enhances their functionality by enabling precise features, such as mapping an athlete's running path in real time, from which distance and speed can be calculated. Another significant application is personal safety, particularly for children or elderly individuals who may be at risk of getting lost. In such scenarios, GNSS allows family members to monitor their location. Naturally, robust cybersecurity measures must be implemented to ensure sensitive location data remains secure and inaccessible to unauthorized parties.
Today, GNSS-enabled wearables are ubiquitous, and it is rare to find a smartwatch without built-in positioning capabilities. The meter-level accuracy provided by these systems is generally sufficient for most applications. But what if even higher precision is required?
The size and design of GNSS antennas and receivers have long posed challenges for wearable technology. Industrial-grade antennas used in vehicle navigation or geodetic surveying, while highly accurate, are far too large and heavy for integration into body-worn devices. Despite these limitations, manufacturers continue to push the boundaries of miniaturization, gradually enabling more advanced GNSS functionalities in smaller, lightweight devices.
One exciting area of current research involves using GNSS not just to track a single point on the human body, but to reconstruct full-body movements. This innovation could revolutionize fields such as human motion analysis, sports science, and ergonomics, allowing detailed studies to be conducted in natural, uncontrolled environments. The potential applications for both research and practical use are vast and promising.
This is exactly what we aim to achieve within the scope of our ongoing GESTUS project. A multisensory IMU-based system generally enables precise human motion reconstruction for short periods, but it inevitably degrades after several minutes or tens of minutes due to error accumulation.
By adding several compact GNSS receivers and antennas, along with complementary correction algorithms, it is possible to mitigate this IMU degradation. Although GNSS solutions are not particularly precise, especially in conditions of poor satellite visibility and intense dynamics, their advantage lies in the complete absence of error accumulation and temporal degradation, as we have previously demonstrated in our experiments with foot trajectory reconstruction in the REMOT project.
In the GESTUS project, we are collaborating with the University of Genoa and other leading companies in the fields of GNSS, IMU, and wearable devices to synthesize our expertise into a new product. The goal is to provide athletes and sports scientists with a precise, continuous, and portable motion analysis system that is independent of external devices.
For more information: https://www.gter.it/health-wearable-2024/
