An Underwater Navigation System Powered by Sound

GPS isn't waterproof. The navigation system depends on radio waves, which break down rapidly in liquids, including seawater. To track undersea objects like drones or whales, researchers rely on acoustic signaling. But devices that generate and send sound usually require batteries -- bulky, short-lived batteries that need regular changing. Could we do without them? From a report: MIT researchers think so. They've built a battery-free pinpointing system dubbed Underwater Backscatter Localization (UBL). Rather than emitting its own acoustic signals, UBL reflects modulated signals from its environment. That provides researchers with positioning information, at net-zero energy. Though the technology is still developing, UBL could someday become a key tool for marine conservationists, climate scientists, and the U.S. Navy. These advances are described in a paper being presented this week at the Association for Computing Machinery's Hot Topics in Networks workshop, by members of the Media Lab's Signal Kinetics group.

Passive Sonar?

[Comboman]

How is this different from Passive Sonar which has been around forever?

Re:Passive Sonar?

[timeOday]

These actively reflect back acoustic energy, and because they are active they can modulate the return signal to carry encoded information from onboard sensors. The story doesn't mention RFID but to me they sound more like RFID than GPS.

It does certainly seem like these would have national security ramifications since underwater is the only place where you can move yet hide. So just as you would not be allowed to leave a bunch of sonobuoys bobbing around in certain waters, so it would be with these.

Re:

[saloomy]

This makes no sense. Batteries can easily be recharged by the movement of the object its on, and GPS can still work because when the tracked object surfaces, it can hone in on its location. Thats how existing marine trackers work. Once at surface, they transmit their information. Here is a live system that does just this: This tracks sharks [ocearch.org].

Re:

[Ungrounded Lightning]

How is this different from Passive Sonar which has been around forever?

Passive sonar is about identifying targets by quietly listening for sounds you didn't send at them - either sounds they generated themselves or echos of sonic "illumination of opportunity" from other sources - the sonar equivalent of seeing things around you by light reflected from the sun.

This is a form of active sonar: You send out a suitable probe. The target uses the energy in the probe to generate a reply - at another frequency or

Re:

[account_deleted]

Comment removed based on user account deletion

C14 diamond battery?

[WindBourne]

I wonder if the C14 diamond idea would work on something like this? Simply charge a capacitor to allow it to emit a signal every so often.

Re:

[nospam007]

"Simply charge a capacitor to allow it to emit a signal every so often."

  4, 8, 15, 16, 23, 42

I misread the headline

[IHTFISP]

I initially misread the story's headline as ``An Underwear Navigation System Powered by Sound''. I was about to crack a joke about flatulence navigation.

I clearly need to get out more. This whole COVID lockdown thing has rotted my brain. (Yeah, that's my excuse. (*wink*))

Re:

[antdude]

At least you have a brain. I don't have one! :(

Come on MIT

[alienpotato]

Why didn't they call it Battery-free Underwater Backscatter Localization (BUBL)? I'll get my coat.

UBL??

[Mister Transistor]

Then they can use UBL to find UBL in his watery grave!

(ducks)

Prior art: Cetaceans

[rossdee]

Whales, dolphins etc

Tracking whales ... with sounds ...

[BAReFO0t]

Animals that communicate with sounds, and are easily disturbed by noise.
What complete amd utter voter came up with that one??

been done already

[AndyKron]

I think whales already do that