Underwater Navigation Device

[hudson]

This would be a most welcome device, wish you the best of luck bringing it to the market.

Do you foresee a problem with the magnetometer around wrecks?

 

[kacem78]

the compass alone yes, it will have an issue close to any metallic object, such as wrecks, but the Compass is not used alone in the IMU, it's always compensated with the 3 Axis Gyro.

in an ideal world, i would say even the compass is not needed, if you can calibrate the heading onboard , then just leave the Gyro and Accelerometer predict the heading, but for better accuracy the compass is used.

i do have a 3 magnetometer in my diving computer, and i had never had a single issues with wrecks,

anyway , thanks for encouraging me to get this done quickly and get it to all the diving community soon, as i'm my self a frustrated diver when it comes to find my way back.



kacem

 

[Noboundaries]

Having flown pre-GPS aircraft equipped with Inertial Navigation Systems, Kacem's device makes sense. A small size is paramount to a diver. Seems the power supply to drive the gyros could be an issue too. All doable though with today's technology.

In fact it looks like people are already developing and incorporating nanogyroscope technology. Nanogyroscopic stabilizers in camera phones is one example. Nanogyroscopes that could sense direction along an axis would solve all size and power problems.

Fun stuff. Can't wait to see the finished product Kacem.

 

[kacem78]

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

 

[Thalassamania]

The Honeywell chip looks good.

 

[kacem78]

correct, the two chipset from Honeywell and Analog devices are the best at this time for this kind of application,

the prices are still high today, : the Honeywell Magnetometer is in the range of 120$ for low volume, and the Accelerometer + the Gyro in one chip from Analog is in the range of 250$ for low volume

add to that a nice CPU like the ARM7, in the range of 40$ for low volume, and an LCD 3-4" a Nokia one at 60$

you see for a nice prototype, I'm not far from the 500$ as a HW BOM only.

of course there is other chipset very cheap like the freescale one.

but i'm a diver my self, and if today we are not that using the scuba scooters that much , it's because the anxiety of not finding our way back.

and for such a way of diving, high speed diving I may say the choice for very accurate sensors is really the first priority to avoid any accumulation of the drift over the time.

anyway, I will consider this topic 6 months from now, I'm more busy by integrating the Kalman filter at this time.


kacem

 

[TwistedGray]

Interesting read...

 

[kacem78]

thanks TwistedGray

i saw your web site, and looks like this product works for you.

kacem

 

[TwistedGray]

Yeah but I wouldn't plan on a huge market. A steady one...yes, but a huge one...no

 

[Rhone Man]

If you brought an u/w GPS to market you would be killed in the rush. I don't think it needs to be able to do anything more sophisticated than help people get back to their entry point, although if you could add an ability to find u/w waypoints, so much the better.

What would people pay for that? I would have thought anything less than US$500 and you have a queue. Above that, I think they would still sell, but you it won't become de rigeur in the same way that a dive computer has.

One thing I have never understood is why no one has popularised an underwater beacon locator, so that you can find your way back to the ascent line by "pings". I would have thought that would be a cheap and simple innovation that would make a pack of cash for someone.

Good luck bringing it to market - I think the idea has huge potential.