Researchers have developed a technique for measuring speed and distance in indoor environments, which could be used to improve navigation technologies. The technique uses a novel combination of Wi-Fi signals and accelerometer technology to track devices in near-real time.
“We call our approach Wi-Fi-assisted Inertial Odometry (WIO),” says Raghav Venkatnarayan, co-corresponding author of a paper on the work and a Ph.D. student at NC State.
“WIO uses Wi-Fi as a velocity sensor to accurately track how far something has moved. Think of it as sonar, but using radio waves, rather than sound waves.”
In outdoor environments, many devices use GPS to correct their IMUs. But this doesn’t work in indoor areas, where GPS signals are unreliable or nonexistent.
“We created WIO to work in conjunction with a device’s IMU, correcting any errors and improving the accuracy of speed and distance calculations,” says Muhammad Shahzad, co-corresponding author.
The researchers wanted to test the WIO software but ran into a problem: they could not access the Wi-Fi network interface cards in off-the-shelf devices such as smartphones or drones.
To address the problem, the researchers created a prototype device that could be used in conjunction with other devices. The researchers found that using WIO improved a device’s speed and distance calculations dramatically.
For example, wi-fi signals devices using WIO calculated distance with a margin of error ranging from 5.9% to 10.5%. Without WIO, the devices calculated distance with a margin of error from 40% to 49%.