Shrimp inspire undersea navigation solution

The cylinder shows the polarization states that the bio-inspired detector observes; polarization states predicted by the single-scattering model. (Image: Study authors)

With so many recent improvements in navigation, positioning and mapping, you’d think we could place things pretty much anywhere on the globe.

But what about under the ocean? Satellite-based GPS only works to a depth of about 20 centimeters.

To find a new method of underwater positioning, an international team of researchers turned to the humble shrimp. The crustacean uses polarization — the bending, refracting and scattering of light as it passes through water — to find its way.

The team is developing an underwater geo-localization system that uses polarization of light to calculate the position of objects. The study, published in the April issue of the journal Science Advances, carries the promise of increased accuracy in navigation, exploration and deep-sea search-and-rescue missions.

“The rich repertoire of underwater polarization patterns — a consequence of light’s air-to-water transmission and in-water scattering — can be exploited both as a compass and for geolocalization purposes,” write the authors. “We demonstrate that, by using a bioinspired polarization-sensitive imager, we can determine the geolocation of an observer based on radial underwater polarization patterns. Our experimental data, recorded at various locations around the world, at different depths and times of day, indicate that the average accuracy of our geolocalization is 61 km, or 6 m of error for every 1 km traveled.

“This proof-of-concept study of our bioinspired technique opens new possibilities in long-distance underwater navigation and suggests additional mechanisms by which marine animals with polarization-sensitive vision might perform both local and long-distance navigation.”

Read the full article.