Researchers from N.C. State and Carnegie Mellon University have partnered with Disney Research to develop a technology that will take the guesswork out of tricky referee calls in American football.
By placing a low-frequency transmitter inside a football that relies on magnetic fields to indicate positioning. With the transmitter integrated into the football, the ball will still be within the standard deviation of acceptable professional football weight.
David Ricketts, an associate professor of electrical and computer engineering and senior author of a paper describing the work, explained how the football-tracking system works.
“Basically, the football emits a magnetic field like a magnet,” Ricketts said. “We put antennas around the field to measure the magnetic fields that the magnets put out.”
A GPS, cellphone or Wi-Fi all use an electric and a magnetic field, and the electric field doesn’t transmit through the body. What sets this research apart is the technology’s ability to transmit magnetic fields through human beings. Additionally, the magnetic fields are able to give accurate orientation, so if a football is pointed up toward the sky or if it is laid down on its side, the transmitter can give the position of the football.
“We use a magnetic field, and humans are transparent to magnetic fields, so if 22 players are on top of the ball, or if no players are on top of the ball, we get the same magnetic field at our antennae,” Ricketts said.
Other methods using high-frequency radio waves have been tested to track footballs, but these radio waves lack the abilities of the magnetic fields. Radio waves are often absorbed by players on the field or hindered by environmental factors in the football arena.
“We’ve been told that in American football, the chains they put out to measure distances are only accurate to about a half a football,” Ricketts said. “Our hope is that this technology would allow the same accuracy, but more importantly, you would be able to see the football when the eyes can’t.”
This tracker will allow the referees, analysts and viewers watching the game on TV to visualize the ball’s location.
Ricketts said the technology will have many uses within the sport due to often confusing situations referees face on the field when trying to make calls.
“It will be important when you have a rush on the goal line and you can’t see where the ball is,” Ricketts said. “Did it go over the goal line or not? This will allow you to see that.”
This technology could have multiple applications outside of the football stadium, Ricketts said.
“It’s basically a general sensor to measure the position and orientation of an object, and because it uses magnetic fields, it would be ideal,” Ricketts said. “For example, you could build a bracelet that measures gestures, and you can put it on an athlete’s leg or arm and measure their performance while doing sporting activities. You can also use it to track animals.”
According to Ricketts, the technology to install the magnetic transmitters would be affordable for consumers, and the transmitters that go in the football would cost just a few dollars.
