How a virtual fence could make dangerous work safer
High hazard industries could be a little less hazardous in the future, if researchers can find a way to thwart the biggest challenge to promising new technology: trees.
The same kinds of collision-avoidance technologies used by self-driving cars could help workers monitor their surroundings through a mobile virtual fence, or geofence, according to NIOSH-funded research at the University of Idaho. Geofences could be used to maintain safe work areas in logging, for instance, by sending alerts of approaching hazards.
Heavy equipment, falling trees
Logging is one of the most dangerous occupations, with the highest rate of work-related death in the U.S. in 2015, according to the U.S. Bureau of Labor Statistics. Workers are killed by heavy equipment and falling trees, and the hazards they face are exacerbated by rough terrain and weather.
While the technology is not currently precise enough to define the borders of safe work areas on its own, there is potential for future applications, the researchers reported in the journal Sensors.
Global navigation satellite system and radio frequency transmissions could relay information about the positions of workers and logging equipment from small transmitters, or personal location devices, which then send an alert to the workers wearing them.
Trees could block signals
One of the challenges to using geofences in this environment is the tree canopy, which could block signals from the satellite.
The fieldwork for the study took place in a section of the University of Idaho Experimental Forest. Using various calculations such as walking pace, alert timing, and alert intervals, researchers tested the ability of a geofence to define the safe work area around heavy equipment by sending alerts to other workers who may be too close. For the second part of the study, the researchers used the field information to create a computer simulation of mobile geofences and then calculated the number of incorrect alerts.
Field test results showed that the accuracy of alerts varied significantly depending upon the angle that a potential hazard approached the geofence. Most of the inaccurate alerts occurred too early, before the object reached a certain location, rather than too late. The simulation test confirmed these results. Overall, the study results indicate that geofences may help to increase general situational awareness of a worksite in logging and other occupations, according to the researchers. At the same time, the relatively high number of inaccurate alerts shows that geofence alerts, using current global navigation satellite systems (GNSS), are not precise enough to define safe work areas, unless combined with other methods that can accurately correct for the incorrect alerts. Additionally, the authors note that new personal location devices are becoming more accurate over time because newer devices can integrate satellite data from multiple systems, including U.S., Russian, European, and Chinese. These satellite systems will have increasing position accuracy in forest environments as more satellites become available over the next 2–3 years.
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