Underwater GPS

[jseyfert3]

That is a necessary "cheat" to make it work. You really want to dive like that?

Well, no. Hence my disappointment when they mentioned current correction and tracking the diver's swimming motions.

 

[NAM001]

A few errorseconds in your response KWS. First off, it might be worth your while reading up on gyros, accelerometers and IMUs.

Gyros detect rotational movement, and quite easily correct for tilt and rotational movement such as on your arm.

And most phonestablished absolutely have accelerometers or IMUs. Look up the android app "send me to heaven"... if it's still available. It usespecially the phones accelerometer to determine how far you can throw it into the air and catch it again. It does sanity checks against gravitational forces to ensure it is thrown and not launched by some other mechanism. If you can still download it, I don't suggest you try to top the leader board

The other much used example of a phone's accelerometer is with the Samsung VR headset... it's the accelerometer that maps your head movement into movement in the VR world that you're immersed in.

And while I'm at it, if you use Facebook, you might have seen people posting panoramic photos, and as you move your phone left and right and tilt up and down it moves around the photo. That's the accelerometer at work,

I am more than passively familiar with gyros, and accelerometers. I know phones have accelerometers but i do not think they can do what is being attempted by this item. Your phone does not track your position solely with a accelerometer. It works with a basis of other technologies such as gps to supplement the output. The examples are not the same as navigetion with them. This appears to act more like a dead reconning device. Accurate enough to perhaps determine a direction of motion without a use of a built in compass. I suspect that when the torque from the change in motion returns to zero change it uses that value to base speed and direction on. I also susect that you have to point the device in a forward direction to maintain accuracy.

Your gyro example also continues to out put torque results when no relative movement occurs such as when you drift in a current. no matter what arguement you present you still have to work around the unstable platform. That seams to be acknoledged buy discussed current calibreation process. From the picture i cant tell how big it is but if it is sizable then those are handles on the sides to maintain that relative axial position while using it. That way in the line of motion sensors and across the line of motion sensors remain just that.

Your accelerometer example with panaramic viewing only needs to use it for shifting angle of view. you could most likely walk around a room and make it show panaramic views based on basic motion direction. you could walk around a virtual table and look at all sides. That dooes n ot take a lot of accuracy. Even with all the errors in the process it would probably be pretty acccurate used over a short distance. The longer used the more combined errors would accumulate. I suspect that there will be a unique skill to get good results from it.

 

[Captain Swoop]

Aircraft inertial navigation systems have a drift of about half a mile per hour. Compared to this device they are much more sophisticated and in a much more stable environment.
If an accurate and reliable system can be developed and miniaturised to allow it to be worn on a wrist I will be very impressed.

 

[NAM001]

Aircraft inertial navigation systems have a drift of about half a mile per hour. Compared to this device they are much more sophisticated and in a much more stable environment.
If an accurate and reliable system can be developed and miniaturised to allow it to be worn on a wrist I will be very impressed.

so would I

 

[lowviz]

@KWS They do have one big advantage over sub navigation. They do not need to remain passive (stealth).

I would look at LIDAR. Optical diode laser. It is well established for tracking tiny particles in the air and thus getting wind-speed. Laser Doppler velocimetry - Wikipedia

Running it in reverse, put the detector in the moving medium (on the diver) where it is now sensing the BIG moving hard bottom. This input channel could be a first approximation for a drift (moving water) correction.

 

[Dish]

So let's say I jump off a tied-in boat. I will very quickly come to the current's velocity and direction, it will happen during all the sensor overload of the splash itself. The sensors on me need to balance all the forces of the splash and come up with a resultant, that of the current itself. That is the only hope of tying the two frames together with respect to distance.

Is this even remotely possible IRL?

Every one of those requires an acceleration. You can be pretty sure how you moved about in your reference frame, but also need to know the really big detail of where the boat is...

I was concerned about the unit losing its mind during the splash, as well. They only way I could divine a fix was to require the diver to hold onto the boat or the mooring line, allow the unit to get one more GPS fix and stablize, then start your dive. I suspect you could stay on the surface and drift to get a similar result... depends on how the system achieves its origin state.

 

[NAM001]

@KWS They do have one big advantage over sub navigation. They do not need to remain passive (stealth).

I would look at LIDAR. Optical diode laser. It is well established for tracking tiny particles in the air and thus getting wind-speed. Laser Doppler velocimetry - Wikipedia

Running it in reverse, put the detector in the moving medium (on the diver) where it is now sensing the BIG moving hard bottom. This input channel could be a first approximation for a drift (moving water) correction.

I would not look at that at all given the task is to make something a normal diver can PURCHASE and use.

 

[jseyfert3]

I am more than passively familiar with gyros, and accelerometers. I know phones have accelerometers but i do not think they can do what is being attempted by this item. Your phone does not track your position solely with a accelerometer. It works with a basis of other technologies such as gps to supplement the output. The examples are not the same as navigetion with them. This appears to act more like a dead reconning device. Accurate enough to perhaps determine a direction of motion without a use of a built in compass. I suspect that when the torque from the change in motion returns to zero change it uses that value to base speed and direction on. I also susect that you have to point the device in a forward direction to maintain accuracy.

Your gyro example also continues to out put torque results when no relative movement occurs such as when you drift in a current. no matter what arguement you present you still have to work around the unstable platform. That seams to be acknoledged buy discussed current calibreation process. From the picture i cant tell how big it is but if it is sizable then those are handles on the sides to maintain that relative axial position while using it. That way in the line of motion sensors and across the line of motion sensors remain just that.

GPS is the primary, if not only, means of positioning for most apps. Well, that and GLONASS (Russia's GPS equivilent). Between GPS and GLONASS my phone can usually get a lock on 12 satellites at once, continuously. Why would you need anything else? (For above surface use)

Why continue to put out torque results when no relative movement occurs? Accelerometers measure linear acceleration, gyroscopes measure rotational acceleration. So you rotate, when you start rotating the gryo can measure this rotational acceleration, when you stop rotating it can measure the rotational deceleration.

Gyros detect rotational movement, and quite easily correct for tilt and rotational movement such as on your arm.

They detect rotational acceleration, not movement. They can be used to sense and calculate rotation, but actually the accelerometer would kick in after that. In the absence of any other forces, a 3 axis accelerometer always knows what way is down, due to the force of gravity. So a gyro can be used to measure rotation, and the accelerometer can be used to do sanity checks and correct for drift of the gyro, except for rotation about the vertical axis (yaw), but this drift would be corrected for with a compass.

Aircraft inertial navigation systems have a drift of about half a mile per hour. Compared to this device they are much more sophisticated and in a much more stable environment.
If an accurate and reliable system can be developed and miniaturised to allow it to be worn on a wrist I will be very impressed.

From the picture i cant tell how big it is but if it is sizable then those are handles on the sides to maintain that relative axial position while using it. That way in the line of motion sensors and across the line of motion sensors remain just that.

Well, several people have said this, but the sensors are not on your wrist. The sensors are in a device you strap to your leg. In the video, this is strapped to the back of the diver's calf, probably 8" long, and several inches on each side. There is a wireless link to a wrist unit, which is a display and possibly the brains of the thing, but doesn't have sensors (or at least doesn't have as many as the leg unit). The part on the wrist right now is a big, bulky thing with a handle on both sides, and is the part they need to shrink down. (It's mainly so big because they literally threw an off the shelf tablet inside a waterproof case with some other electronics, as you can see in the video. Cheap way of making a prototype)

 

[stiebs]

@KWS, yes , I realise my accelerometer phone examples are in a different league to navigation, which actually supports my position from previous posts. The point of that post was in response to your comment that phones don't have accelerometers. They absolutely do, but they are not used for any sort of navigation because it is simply not viable.

A smartphone uses a combination of GPS, WiFi and 3G/4G triangulation for location services. It will always use GPS unless unavailable when it will fall back to the other two.

GPS is also used for elevation.

Accelerometer is used for the things I mentioned above, plus other minor movement detection such as turning the screen on if you pick it up (more common example in the Apple Watch, which turns the screen on when you turn your wrist)

I'm in absolute agreeance that in to to achieve what these people are trying to do requires a combination of many types of sensor technologies, and will be absolutely blown away if their current prototype can actually do it, let alone a miniaturised version.

A dead giveaway for me so far, is that they sell the wonders of it, and say it is working, but so far I have not found any evidence of them offering it up for independent use or review. If they are that confident, it should absolutely be patent protected and available for external review / input

 

[jseyfert3]

I don't know why I'm defending them, personally I doubt it'll ever happen, but I guess it would be cool if it does.

@KWS
I'm in absolute agreeance that in to to achieve what these people are trying to do requires a combination of many types of sensor technologies, and will be absolutely blown away if their current prototype can actually do it, let alone a miniaturised version.

A dead giveaway for me so far, is that they sell the wonders of it, and say it is working, but so far I have not found any evidence of them offering it up for independent use or review. If they are that confident, it should absolutely be patent protected and available for external review / input

They say it's patent pending, how long does that take? Years, right? They formed in 2013.

According to this site I found, using Google Translate it says they had a net income of -€87,000. So they either convinced some private investors they really could get the product out or are spending truckloads of their own money on it. They certainly haven't (yet) come out asking the public for funds, which to me is a good sign.