Tag Archives: underwater

The Office of Naval Research has filed a patent application on a potentially revolutionary new underwater navigation system. The patent covers:

A method and apparatus for determining the geophysical position of an autonomous underwater system utilizing underwater acoustic modems that exchange broadband underwater acoustic signals. The method of the invention includes the steps of initiating an exchange of broadband acoustic signals between the autonomous system of unknown geophysical position and a base system of known geophysical position wherein the depths of both systems is known.

In English, I think that means a base station at a known location on the ocean floor exchanges sonar pings with clients some distance away, providing a reference point. Using the bearings and timing of the pings, the client unit can figure out its exact position underwater.

What’s so revolutionary is that submarines, divers, and underwater research stations have so far been left out of the GPS revolution, which allows precise navigation just about anywhere on the surface of the earth. Underwater, navigation is pretty much stuck in the 13th century: a compass, a memory of landmarks, and dead reckoning are about the only tools that work. An underwater GPS-type system like this could make it a whole lot easier to locate specific research sites reproducibly, keep submarines from running aground, and prevent divers from getting disoriented.

Unfortunately, the strategy outlined in this patent could also increase underwater noise levels dramatically. With navies already bombarding marine mammals with new active sonar systems, do we really want to start pinging GPS signals throughout the world’s oceans as well? Continue reading →