Underwater Navigation Devices

[scubasteve66]

I’m working at USC as a researcher in the Aerospace and Mechanical Engineering department, where my group has come across some interesting technology. As a project for a class, we are looking into the feasibility of bringing a device to market that would function as an underwater GPS-type navigation device. While we’re working on the best way to do physically do this, we’re also looking into whether or not it is even worth trying. If you would be interested in such a device, or think it’s idiotic, input from anyone is greatly appreciated. If you have a few minutes, please fill out the brief survey below. If you’re time limited, answer whichever questions you’d like. Thanks in advance!

What are your feelings about an underwater navigational device?

What do you find most difficult about underwater navigation?

How long have you been diving, and how has your answer to the last question changed as you’ve become more experienced?

When looking for a specific feature at a dive site (cave, wreck, etc…) how often do you have difficulty find it? If you’ve had difficulties with this, would your rather have a map to look at, or a simple arrow telling you the distance, direction, and depth to the feature?

Have you ever used any devices (other than a compass) for underwater navigation, and if so, what were your experiences with them?

How often have you been separated from your dive partner? Of those times, how many times have you easily found them, and how many took longer than you would have liked?

What would be your biggest reason for purchasing a navigation device (safety, better dives, comfort, etc…)?

Do you use a dive computer? If so, what type do you use, how much did it cost, and what made you purchase your particular model?

How often do you replace your computer, and what will you be looking for in your next one that your current model lacks?

If your next purchase of computer had an option for a practical navigational aid, how strongly would you consider the following features? Please rate from 1= Unnecessary to 5=Important, and add any comments you feel are necessary.

Distance and direction to boat (or dive starting location):

Distance and direction to dive partner (or other divers):

Waypoints for dive features (caves, wrecks, etc…):

Actual map of dive site:

A recorded path of your dive (including air usage and swim speed):

Some facts about you:
Geographic location (state or country):
Do you prefer boat dives or beach dives:
Favorite dive spot:

[kroorda]

Your project sounds very interesting. Do you realize/understand the limitations of RF in water? One inch of water would attenuate a GPS signal to the point that it would be undetectable. Even the US Navy must raise a snorkel/antenna to the surface to receive a "GPS" signal. Nevertheless, if you have idea(s), I would certainly be interested and I would be happy to provide the info you request (above). Best Regards, Kent
PS: I have been diving for 35 year. I have dove many places around the world; favorite probably being the New Guinea area. I am in Colorado, and I have a pretty extensive background in RF.

Steve, I showed your thoughts to a friend of mine who is both a diver and an RF engineer. Here is what he said:

It's impossible to use GPS or other low-powered ultra-high-frequency RF device under water. Only VLF works there in the realm of 100-300KHz. These take impossibly long wire antennas to make work. They have to trail a long wire for it to work underwater on Subs and that will only give them 30-60 bits per minute for data speeds. This compared to the 1100mhz GPS signal that is transmitted from 250 miles up and passes large quantities of data (9600baud or 9600 bits per minute)

He's barking up the wrong tree and using flawed logic here even thinking that it will work. An underwater navigational device would have to work in the ultrasonic realm like our pingers.

[gibson1525]

this has some real potential. i would just like to put waypoints in so i could find a cave, wreck, trap, etc. with 100% accuracy. it would be nice to be able to jump in the water and be able to find something without having to worry about missing it. also, maybe think about setting up a website where people can upload the lat., long., and depth for things all over the world. i've been to several well known sites with some well known feature only to have the dive guide say "if i can find it, i'll show you this really neat thing." it would be very nice to be able to have it preprogrammed into you gps before you go so that you know exactly where to go to find what you are looking for.

maybe a feature to think about would be to have the unit automatically put in a waypoint where you descend, that way you could navigate back to your exit point. having a buddy tracker wouldn't be as important to me as i'm always in sight of my buddy.


a path for your dive would be a good feature, with depth also. depth, lat., and long. would be a must for all waypoints. if you are looking for a waypoint, i'd probably like to see where i am in relation to where the waypoint is (with depth, distance to waypoint, maybe even speed and estimated time until you reach the waypoint).

[mitsuguy]

when I read this, all I think is what comes with your basic standard Garmin like GPS - not the streets and maps type, but the type you can download topographical terrains to and set way points and history markers...

make that work underwater, and we're set... then do it for $200 (or less) and we are really set...

it would make diving new sites safer if you don't have someone already familiar with a site... it would also allow maps of past dives to be stored to allow new paths...

[Navy OnStar]

Current and limited visability are probably the two biggest problems with underwater nav. Anything that can fix your exact position (within a couple of yards) would be great. A good size memory to store many sites and a track history would work well for most everyone.

[RoadRacer1978]

I know this is still in the development stage, but what kinda market value are we looking at? Around the current GPS price $200-$500 or something much higher in the $1000's of dollars.

[mitsuguy]

Originally Posted by RoadRacer1978

I know this is still in the development stage, but what kinda market value are we looking at? Around the current GPS price $200-$500 or something much higher in the $1000's of dollars.

you can get an inexpensive, programmable, gps for like $75 now... most all of these inexpensive units even allow downloading of terrain maps, and waypointing up to 500 locations...

[Clanggedin]

The diving community would greatly benefit an underwater GPS device. It can't have a tether and should be able to carry a signal down to at least 100'. That would at least cover the majority of divers which are only OW certified.

As long as it has and can set a waypoint using depth also, then it would be awesome.

[abcitydiver]

without answering your questionaire in detail, yes, yes yes YES!
oh...an Atom 2.

If you build it, they will come. I promise. And though we'd all love this to be afordable technology, "affordable" is relative, and most of us would set up a lemonade stand for a year in death valley to afford this. imho.

[scubasteve66]

kroorda-

We are well aware of the GPS limitations underwater, which is why GPS doesn't exist there. Thank your friend for his input on pingers and ultrasonics; nature is a beautiful thing and often provides the most elegant solution to man's problems (dolphins and bats navigate/communicate the same way). The technical aspects aren't really the problem as we think we've come up with a cool way to deal with them. The real problem for us is what does a diver REALLY need? What I mean by that is simple: if you bound the problem with a solution and say "I need GPS" you're thinking about the possible solution without analyzing the problem. We're more interested in what is the actual problem that needs to be solved, which is why the questionaire doesn't have any technical questions. How a diver finds cool things under the water has nothing to do with what technology ends up being used, and we're trying to find out what's most important to the community as a whole.