Underwater GPS

[NAM001]

lovis what power is needed for such a technology sonar/lidr

 

[lowviz]

Ahhh... You force me to think about this. Huge advances in laser diodes, they are down to low power devices: http://www.ti.com/lit/an/snaa123/snaa123.pdf

If I had to do this, I'd likely make it a stand alone system (in the same enclosure) that offers a single value to the main system anytime the main system asks. Velocity of the water. Just magnitude, no direction. Keep it as simple as possible for a first try. Easy to fuss with this module without messing with your programming. Hardware solution.

You splash, orient yourself, and sooner or later find a nice target that you are drifting towards for your laser pointer. You go still and squeeze the handle to turn on the drift correction for a few seconds while you keep your spot on the target. Done. Forget fancy doppler-shift for now (simple distance measurement and a timer). The first reading is then used to back-calculate to your splash and corrects where you are expected to be. Subsequent readings just go from measurement to measurement.

I would have to REALLY need something like this before I agreed to tie up both hands.

Maybe their efforts would be better spent in developing an underwater AWACS system that could be mounted on the back of a DM.

 

[tridacna]

If implemented as they claim (and reasonably priced), this device will be a major success. No question about it.

 

[Dish]

I believe the Office of Naval Research built a hand-held diver-tracking system for the SEALs, many years ago. It used accelerometers, gyros, and a small low-power high-frequency sonar device that looked at back-scatter from either the bottom or particles in the water. The position came from a Kalman filter based on double-integrating the linear and rotational sensors, with the sonar giving speed over bottom/through the water. It, I think, worked pretty well, but because it had batteries and o-rings, the SEALs did not trust it. If built today, it would be much smaller and cheaper. I admire the spunk of the Ariadna folks, but question their methodology.

Actually, it was the TOWS Office of NRL and the unit was called the CLAM (Covert Littoral Acoustic Mapper). This was a late 90's program. UW navigation without transpoders or beacons is certainly doable and proven.

That said, I like Low Viz' idea. Divers with frickin laser beams? How cool it that?

 

[tursiops]

Actually, it was the TOWS Office of NRL and the unit was called the CLAM (Covert Littoral Acoustic Mapper). This was a late 90's program. UW navigation without transpoders or beacons is certainly doable and proven.

That said, I like Low Viz' idea. Divers with frickin laser beams? How cool it that?

Right. NRL is part of ONR and the money for the project came from ONR.

I've got a little green laser pointer from Big Blue; does that count?

 

[lowviz]

... NRL is part of ONR and the money for the project came from ONR. ...//...

Oh, you mean I helped pay for it? Sweet!

Maybe now I can get access to CLAM details through a dot gov site. I have to pay for this one: http://ieeexplore.ieee.org/document/634375/ How about offering a freebie site to those few who are following this.

Green laser? Nah, maybe CERC is interested...

 

[NAM001]

If implemented as they claim (and reasonably priced), this device will be a major success. No question about it.

That's usually the biting factor.
Anything that the normal guy could afford would not be incentive enough to carry the project through.

 

[tridacna]

That's usually the biting factor.
Anything that the normal guy could afford would not be incentive enough to carry the project through.

I'm not so certain about the 'reasonable price' yet.

Suunto sells the Eon for $1800 (with transmitter) and Atomics and SP have been selling DCs in the same range for years. I think that the market could tolerate a fairly high price assuming that a DC was included. I wonder what their target price is?

 

[NAM001]

I'm not so certain about the 'reasonable price' yet.

Suunto sells the Eon for $1800 (with transmitter) and Atomics and SP have been selling DCs in the same range for years. I think that the market could tolerate a fairly high price assuming that a DC was included. I wonder what their target price is?

I will guess 5k

 

[jseyfert3]

I wonder what their target price is?

"In the range of a high end DC."