To prevent the further spread of COVID-19, the world is shifting to a “new normal” in which social distancing is practiced and contact between people is avoided. Due to early evidence suggesting that the spread of COVID-19 is much more aggressive indoors than outdoors, many companies have begun efforts to monitor workers’ movements and trace contacts to keep offices and factories from becoming new epicenters of infection.

The Need to Monitor

Keeping a safe distance from others and avoiding contact is essential to prevent getting infected with COVID-19. However, there are many situations where avoiding contact with others at indoor locations such as offices and factories is difficult. Hence, there is a growing need for technologies that monitor contact between workers and their movement histories in real time.

Indoor location information can be obtained using various wireless communication technologies including Wi-Fi, Bluetooth and ultra-wideband (UWB). For example, Bluetooth beacons have been deployed at commercial facilities to enable services that provide location-relevant information to customers with smartphones. The positioning accuracy of Bluetooth, however, is only around 3 to 10 meters and is dependent on infrastructure installation.

To be useful for contact tracing of infectious diseases, the number of beacons must be increased to achieve an adequate level of accuracy. UWB technology features high positioning accuracy, but deployment in a wide area would require installation of a large number of radio transceivers and repeaters, putting it at a cost disadvantage.

Solution Based on Geomagnetism

Given this background, a solution using geomagnetism is attracting attention. TDK has developed VENUE, which displays the real-time locations of people by utilizing geomagnetic sensors found in today’s smartphones. Each indoor location has a geomagnetic signature that can be used to ascertain the position of the phone.

There are several approaches to indoor positioning, but geomagnetism, tightly coupled with inertial navigation, optimally balances accuracy, reliability and cost of deployment and maintenance.

“The beauty of geomagnetic positioning is that it works in all large venues whose structures interfere with Earth’s magnetic field, making this an infrastructure-free approach to indoor positioning that is accurate to better than 2 meters,” said Chris Goodall, founder and managing director of Trusted Positioning Inc., a TDK Group Company based in Calgary, Alberta, Canada.

“VENUE provides a position display with even higher accuracy by combining geomagnetic information with information from accelerometers and gyroscopic sensors inside smartphones.”

VENUE requires only the creation of a geomagnetic map that combines an indoor layout map with the geomagnetic data of that particular location acquired through a survey, with no need to install new devices and terminals. This leads to low installation cost. The accuracy of positioning using geomagnetism is better than two meters (6 feet) — sufficient for tracing contact with infected persons. In addition, VENUE provides a position display with even higher accuracy by combining geomagnetic information with information from accelerometers and gyroscopic sensors inside smartphones.

“People may hold their smartphones while walking or put them in their pockets or bags,” Goodall said. “Since the orientation to the user changes constantly, the movements and pedestrian use cases need to be corrected using inertial sensors. Solving these issues was the greatest challenge for practical applications such as tracking, and took our team many years to create, perfect and protect.”

Comparison of indoor location information technologies. (Chart: Trusted Positioning)

Real-World Trial Under Way

Beginning in August, a contact tracing trial among workers is being conducted at TDK’s headquarters in Nihonbashi, Tokyo, using VENUE. Employees carry smartphones with a special app installed, and their positions and movement histories on the floor are combined with anonymous identification information. If an employee is found to be infected, the data will be analyzed to identify people who had contact with that employee within the preceding two weeks, and measures such as stay-at-home instruction will be taken.

This solution not only can identify those who were in close contact with the infected person as primary contacts, but also trace those who stayed in areas where the infected person had been shortly before as potential “area contacts.” Analysis that combines location and elapsed time enables more effective contact tracing by improving primary contact tracing indoors and enabling area-based contact tracing over time.

Ongoing Trial at TDK Headquarters: VENUE displays an individual worker’s tracking data on the dashboard. (Conceptual illustration: Trusted Positioning)

Ongoing Trial at TDK Headquarters: A worker’s durations of stay and…