Leave it to the all-rounder Mantis shrimp to decipher the secret of the underwater GPS.
Two years ago, a University of Illinois researcher, inspired by the dashing, dashing underwater warrior, mimicked his bulging eyes to create a camera capable of picking up polarized light and better detecting some cancers. Now he has used the same technology to develop a global underwater positioning method.
If it does, cracking the underwater GPS puzzle could have widespread implications, from rescue efforts to improved ocean science.
"We collect vast amounts of data with cameras over water, from everything from information about the environment to our personal lives," said electrical engineer Viktor Gruev who has authored a study published Wednesday in the journal Science Advances with Washington University engineer Samuel Powell. "Think about putting this under water."
Global navigation systems rely on a series of satellites orbiting the earth to create places. However, these radio signals can not penetrate water, so that underwater navigation leads to bulky, expensive systems based on ultrasound or gravitational fields. The Department of Defense is now in the midst of years of efforts to develop a network of drones to provide the Navy with its first global positioning system.
Gruev's camera, which he calls "Go Pro Equivalent," can not work without light, but offers a cheaper, more portable solution than what's currently available.
The system works with polarized light in the water. Based on the angle and the time of day, the camera can determine the location within about 37 miles. Gruev says the team is still working to perfect the system and reduce the scope.
In developing the camera, Gruev and Powell also corrected a long-time misunderstanding about the properties of polarized light in water.
In the 1970s, Gruev said that renowned Yale scholar Talbot Waterman discovered that when light is polarized in water, it does not move on a uniform horizontal plane as it does over water. Waterman suggested doing more research, Gruev said, but in the next few decades scientists assumed the light was moving horizontally. But as they turned their camera around the world, Gruev and Powell realized that the angles were not uniform and were constantly changing. Other researchers concluded that the camera could have a problem.
"But I was pretty sure my camera was doing its job," Gruev said.
Instead, his theoretical patterns were related to the location of the Sun and could actually be combined with time to determine locations.
"I asked the question:" How is the light polarized under water? "He said, and could the physical principles of water polarize the light differently?" It took a complicated set of models and measurements and advances in compact camera technology to prove its point underwater.
It's too early to say how marine biologists could use technology. Gruev has some ideas. Like the Mantis shrimp, many marine animals use polarized light to navigate. But what if water pollution changes these polarization patterns and, for example, causes more whales to strand?
"Animals are traveling in strange places," he said. "It is a hypothesis, but it is a plausible explanation"
Swarms of robotic cameras could also be used to locate missing ships and airplanes faster, map the seabed, or track changes to troubled reefs that have occurred in recent years Years have decreased dramatically rising sea temperatures. Or wandering cameras could wander the oceans, constantly sensing and reporting changes.
"They have to carry themselves and provide relatively little power and if they see something, they can return it," said Gruev. "But all the parts are there and it gives us a chance to better understand the sea and where changes happen."