Underwater Navigation Device

[neonistic]

What are your feelings about an underwater navigational device?
I am really looking forward to one.

What do you find most difficult about underwater navigation?
Low viz and currents.

How long have you been diving, and how has your answer to the last question changed as you’ve become more experienced?
12 years. Nothing has changed, I nav on most dives.

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?
If I have a visual reference prior to entering or if I have a course mapped out prior, I usually have no problem. I feel that I am proficient enough at navigating that either way would be fine.

Have you ever used any devices (other than a compass) for underwater navigation, and if so, what were your experiences with them?
No

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?
Never.

What would be your biggest reason for purchasing a navigation device (safety, better dives, comfort, etc…)?
Surface location while kayak diving and bringing it along for return to anchor. Also, mapping new anchor locations (voiding the coral).

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?
Integrated console, compact wrist, basic watch. $700, $300, $300. Redundancy, features, size.

How often do you replace your computer, and what will you be looking for in your next one that your current model lacks?
I don't want to ever have to replace a computer, just batteries (user replaceable please!)

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): 4

Distance and direction to dive partner (or other divers): 0

Waypoints for dive features (caves, wrecks, etc…): 3

Actual map of dive site: 4

A recorded path of your dive (including air usage and swim speed): 5

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

 

[kacem78]

well, i'm using some data to simulated the fusion of the data coming from the different sensor, the as the data are coming in a continuous stream , i need to rearrange them, sample them and get only what is valuable as data to be computed. i tried many models and figured out that the optimum is to get the IMU on a place where minimum of noise, spurious data is generated.

i did a scenario of data generated from my hands, and without moving one step from my position and i was just playing with my hands, my computer was spending his time calculating where i'm , i guess it was frustrating to the PC that after double integrating the Kalman matrix that i was still at the same place.

if by placing the IMU on my back, i would had got plenty of zeros or close to it, which i can eliminate during the sampling phase and not get them to be computed.

try it by your self, and you will figure out that for an optimization point of view, better to lower the overload.

hope this clarify, unless you have other thought.

kacem

 

[Thalassamania]

I'd try putting the IMU on the base of the cylinder.

 

[kacem78]

great that we are in agreement, on my post #44 that where i suggested to put it, on a diver body this is the most stable place; i don't see a diver intentionally doing acrobatics, he will just kill his back

amazing the number of people (industry i mean) that they regain interest on such a device and on such a market, I'm getting newsletter everyday on new MEMS, this is great if it create a competition as the need is real.

kacem

 

[DiveNav]

there is no issue with the power supply at all, all the sensors are mainly based on MEMS technology, they don't consume that much,

the issue is on selecting the right sensors with less noise, and has some auto tilt compensation capabilities

some of them start to become available for the mass market like:

Analog Devices: ADIS16350: High Precision Tri-Axis Inertial Sensor :: Multi-Chip :: Other
this is coming right away from the professional business

look also to this 3 axis magnetometer : http://www.magneticsensors.com/datasheets/HMC6343.pdf

of course the contribution of the automotive, camera stabilization, new Phone generation, virtual reality, motion capture, etc all made the prices to drop down.

kacem

I kacem, I totally agree with you ... advances in the semiconductor industry (including MEMS) will make this underwater navigation device possible very soon. My background is in the semiconductor industry and I made my fortune with navigation devices (GPS chipsets).

By the way, we have been testing (like bringing it underwater ) a similar underwater navigation device (with on board GPS too) since several months. The real trick is to get the Kalman filters working right ..... this is not trivial at all :depressed:

Regards,

AM

 

[kacem78]

my background is from mathematical university, Kalman was by bread and butter for a long time
implementing Kalman it self is not a big deal, i mean by this writing the algorithm it self is not a huge issue, the Extended Kalman needs more spacial understanding, but the big issue as i described is filtering the noise that might be integrated and get you in troubles.

two things that i have to concentrate on, decorelating the MEMS, so that each MEMS could compensate the other errors.
second is the application it self, i'm dealing with divers, with a slow speed and low distance
if you have let say 1° deg drift with a diving speed on a 20mn time, the overall drift is not that big, this is unacceptable on a plane.

other thing that i added is sampling the output, i mean i have a huge matrix that tell me is i have a 1,5V on the yaw this means i have X° , this sampling matrix is helping me to use it as a threshold Min-Max so if i read any number coming from the sensors, i can easily convert it to it appropriate room, the result is great so far.

i did not take the option of adding a GPS, as it doesn't really add any real added value.
however if i have to add something, i will go for a transmitter to send my position to the boat, it's the opposite of the pinger of today.

kacem

kacem

 

[TwistedGray]

For what its worth: it was built, it was marketed, it never developed a market: Dive Tracker.

That's because we stopped selling to them...

We really don't market the product at all. We spend a lot of our time engineering other "stuff"

I have high hopes for Kacem's product though and hope to see it completed.

 

[kacem78]

i did not give up, still working on it, some progress so far,

will keep you updated,

kacem

 

[TwistedGray]

Any updates?

 

[Rhone Man]

For what its worth: it was built, it was marketed, it never developed a market: Dive Tracker.

Just as an aside, I put this pinger on my wish list with LP, and for all bar about 3 days since that date it has shown as "sold out". I suspect it may be a problem getting the product to market rather than finding a market for the product.

Still not nearly as exciting as the idea of an u/w tracker.