Patent Filed for Underwater GPS 236
Matthew Sparkes writes "GPS doesn't work underwater, as the signal cannot reach the satellite from a submersible, but researchers have now patented an add-on to the system that could provide GPS navigation for submarines. A base station is tethered to the sea bed at a known depth and GPS location. A submersible anywhere in the area sends out a sonar pulse to which the base station replies with a signal, giving a GPS position and depth as well as the bearing angle from which the submersible's request arrived. The submersible then uses its own depth, which is easily measured, plus the round trip pulse time and the bearing angle sent by the base, to calculate its own position."
Great! (Score:5, Funny)
How long before lost submarines are meandering up our rivers and streams because the GPS mapping told them this was the way to go?
On a slightly more serious note, no self respecting spy submarine will emit a ping to this service ever. There is no way you would want to give your position away so freely.
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Getting
Re:Great! (Score:4, Interesting)
But if it's been moved by a seismic event (earthquake, volcano, etc) or a bunch of cheeky kids (aka. "terrorists") or even a large marine mammal, well, all bets are off...
Re:Great! (Score:4, Interesting)
Re:Great! (Score:4, Funny)
one ping to rule the world.
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"bring them all", "find them", "In darkness"...
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This isn't the cold war anymore - most of our subs probably operate loud and proud most of the time.
Regardless if this is the Cold War or not, there is no way our subs are broadcasting their position. We wouldn't be spending millions to develop anechoic coatings and other sound controlling materials for these boats just so we can tell the world where we are. In addition, IIRC, sub patrol routes to this day are not known to anyone except the captain in the sub. They are given a very general patrol patrol area and cruise it as they see fit.
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The fact that our military submarines are equipped with active sonar indicates that they probably use it sometimes. Navigating in and out of ports, for example. This would be one more use for those times when stealth is not important, plus as mention
Self Respect. (Score:2)
Yarr girl, better you surface to get a proper fix!
Which way do those signals go? (Score:5, Informative)
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This is not GPS! (Score:5, Informative)
This thing is not GPS. It is sonar ranging that just happens to also includes the GPS locations of the bouys to help give a true position. Doing sonar positioning requires that you know where the bouys are and GPS provides a very good way of doing this.
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Also, I am just guessing here. Anyone who drives a sub, and doesn't know where they are, has bigger problems th
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hmm (Score:2, Interesting)
So instead of being available to anyone who can get the signal its only available to those who can communicate with it. This will probably limit the number of positioning systems that can be used at one time. I hope they will make provisions for emergency uses of the system.
Great (Score:5, Insightful)
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It is the only thing we have for deep water wireless comms, and sensors radio waves don't propagate well. Lasers also don't work very well. Sonar is the best we have. It has been refined so it is not nearly as bad as it was. The Navy has been experimenting with higher power levels to increase resolution. That's where the animal suffering comes in.
Earn your billion dollars and find another way. I personally like microwaves.
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Fish is a good option especially if its already cooked and ready to eat.
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It makes me wonder what we are ... (Score:2)
I wonder if they military think-tanks would like it, to have a sound blasted every x seconds towards their house/bedroom?
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When whales and dolphins have the means to fight back (depleted uranium shells, subs) then I'll start to be worried. Until then, it's primate rule.
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How about spread spectrum sonar? (Score:2)
Although I have not heard of this being done, it could make a lot of sense to use spread spectrum sonar, for ranging anyway. Spread spectrum allows you to get far better signal to noise ratios meaning you can work with far lower signal power (for example, GPS receivers use this to cope with signal strengths that are below thermnal noise). This could give you active sonar without being too obvious to the enemy and without messing up the whales.
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Well, ANY active sonar is too obvious to the enemy. I don't want to be excessively paranoid, but remember that "caterpillar" drive from The Hunt for Red October? I realize that was just a movie, but quite a few years ago a Japanese company demonstrated a caterpillar drive on a small surface craft. It was not very efficient, but that was in the public sector years ago. I'm betting that we're using those already. Anyway, rant aside, the sonar systems in submarines can actually identify known patterns of subm
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For long psuedorandom number sequences you could potentially reduce power by a factor of 1000 or so. This stuff could look like white noise, so if the signal levels can be held low enough then it will be ve
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Cetaceans v. Bush (Score:2)
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There isn't a "mentality that convinces us that using active sonar all day is a great idea".
There's an actual use for running sonar all day long, and people use it.
If sharks, whales and whatever can emit signals to confuse our sonars in return, more power to them. But otherwise, the weaker should adapt. It's how evolution works and we're part of it.
Tha
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So if I meet you, I should fucking strangle you. If you can adapt and get out of it, then you can live. Otherwise, you should just choke because you're weaker.
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Are people randomly mounting sonars hundreds of times more powerful than needed, and used for absolutely nothing, but "proving a point"? And am I defending this kind of abuse?
In which case, you can come and try to "fucking strangle" me, psychopath.
Right. We're going to restore the species we've driven to extinction. And then we're going to flap our ar
Re:Mod parent up (Score:5, Funny)
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That'll send all the eco-friendly folk after me, but: we don't need whales. What are you using a whale for?
Species go extinct and come into existence every day. We're moving this process much faster, but it's still something to think about. It's not that the other animals care about people very much, does a mosquito think about the impact on human healt
Stupid question .... (Score:2)
What is the current mechanism of position-fixing used for subs? Or is it more of the 'traditional' type of navigation where you know where you started, what direction you travelled, how fast and how long?
I'm actually surprised subs don't have an analogue to GPS. Then again, admittedly, I don't know much about subs or most things nautical.
Cheers
Re:Stupid question .... (Score:4, Informative)
Subs have highly accurate inertial navigation systems. I've seen one on of the labs at Stanford where they develop the sensors, and it's amazing. It's kind of like a warehouse, with one of those huge 20 or 40 ton cranes. They use the crane to haul large masses around, and the sensors are able to detect the variations in the gravitational field caused by those objects.
On top of that, the navy has all sorts of charts of the sea floor, many of which are probably classified to some degree or other. Subs can use "landmarks" on the sea floor to determine their position. Since highly precise navigation is usually only important in coastal waters, this works pretty well.
Ocean Mapping Still Limited (Score:2)
By the way, here [tamu.edu] is a free oceanography textbook!
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Apart from the vastness of the ocean and the outdated charts, there is another reason why the topography of the seabed could be poorly known: Some governments hang onto their information. How much exchange of information is there?
So, governments do classify their charts. Are you claiming that one crash proves the system doesn't work "pretty well"?
As far as I know... (Score:2)
Subs that are near the surface can send up tethered bouys to contact satellites for communication and location purposes, of course. I don't know if there are any position-i
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This system, however, as a supplimental to the existing systems used in navigation, would provide greater accuracy and a means to recalibrate existing systems.
I can see this being used in the future to allow submarines the ability to navigate more accurately, even away from a GPS buoy, through shallow areas, thanks to the correction from any drift they may have encountered since their last surfacing.
Inertial guidance, dead reckoning, undersea terrain tracking and of course, t
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The current mechanism is, best as I know, inertial navigation systems periodically recalibrated by GPS when the submarine is at a depth to use GPS, with dead reckoning, as always, the ultimate fallback.
Certainly, Tom Clan
Re:Stupid question .... (Score:4, Interesting)
Basically the principle of operations is simple. You start at a known position and speed. If you continually integrate your acceleration (readily measurable), you know your instantaneous velocity at any point in time. Integrate that and you have your position at any point in time.
The big advantage of inertial navigation is entirely self contained. It requires neither signals from the outside nor does it send signals to the outside. I suppose the subs can rise to periscope depths every so often to compare their position to GPS.
My late father in law worked on inertial navigation systems for the Apollo program and the Trident Missile program. Remember the Apollo 13 movie, where they're so worried about "gimbel lock" That was the one way you could head the space craft in such a way the gyros could not move freely; once that happened, you didn't know where you were, at least not enough to get the right reentry path that would get you into the atmosphere without burning up or missing the Earth entirely. He worked on those gyros. Later he worked on laser "gyros" that didn't have mechanical parts to lock up.
Once he visited the naval base in Alameda, bring a suitcase sized inertial navigation instrument from Cambridge MA. The device was precse enough to tell him that the naval base was using wrong figures for their geographic position.
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Your customer sets the design (Score:5, Interesting)
The primary customer for something like this would probably also be the military, so I imagine the actual equipment would be passive as well. There's no persuasive reason to make the sensors wait for a query, just have them send out a pulse at regular intervals that contain their location, a precise time stamp, depth and water temperature. This is enough data for a passive submarine to use to calculate position (the depth and temperature affect the propagation of sound waves). There would be imprecision because the speed of sound is variable, of course, but you'd have a system that won't give away the presence of a submarine the way you would if said sub was "pinging" for the info.
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I don't think that it would be out of reason to see a commercial/scientific version of something like this to eventually come along. It could improve the quality and reduce the cost of underwater surveying or other bathymetry. Such users would be less concerned about having a stealth technology that the Military would so strongly desire.
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Re:Your customer sets the design (Score:4, Interesting)
1. it's an active system. The military avoid the use of active sonar on subs as much as possible.
2. it's impractical. These beacons would have a range of maybe 100 km, so you'd need to seed lots of them if you wanted to cover a large area.
3. the beacon can be compromised by the enemy.
The only military use I see is to aid navigation on the approaches of the sub's home port, so it can stay underwater as long as possible. Even then, those approaches are mapped accurately enough that they can navigate using inertial navigation.
Due to #2, I expect this system will be popular in situations where you operate in a limited area, but need accurate positioning within that area. Scientific exploration and sea mining/drilling operations come to mind. Submarine cable operations as well, perhaps (for accurate positioning in relation to the ship).
All your GPS base... (Score:3, Insightful)
Nice thing about satellites is that they're unaffected by earthquakes and giant squid... but whoever implements this is probably smarter than I am so I won't worry about it.
deserves a patent (Score:4, Insightful)
Unlike most software patents.
Re:deserves a patent (Score:4, Funny)
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I'm curious why you think that. I had just the opposite reaction. It seems too obvious to be patentable. It is analagous to location systems in use on land and in the air, the only difference being that you use a signal that passes through water with little distortion, namely sonar, instead of one that doesn't, such as RF. Why is this a unique, non-obvious, innovation?
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Unlike most software patents.
Are you "skilled in the art" of submarine signaling and GPS? Maybe those silly software patents look just as unique to submarine experts.
software portion of patent (Score:2)
% ltpdirect.m
% local tangent plane position from range and azimuth
% good for distances less than 10 kilometers
%
function newpos=aproxdirect(pos,range,azimuth);
global DATUM
delta_east=sin(azimuth)*range;
delta_north=cos(azimuth)*range;
n=nphi(pos.lat);
m=mphi(pos.lat);
% convert here changes in meters of easting and northing
% to changes in longitude and latitude
newpos.lon=pos.lon+delta_east(n*cos(pos.lat));
newpos.lat=pos.lat+delta_north/m
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This is better than Doppler, Why? (Score:2)
How many base stations, what kind of range before a sub has to send out a pulse that would fry Moby Dick?
And wont this say to every other sub; "Hey MOFO, I'm over here, about to light up your ship, baby!"?
Who needs it?
roll call (Score:2)
same old story (Score:5, Funny)
Doesn't work like that at all (Score:2)
GPS satellites transmit the time, the GPS receiver receives these transmissions are uses the differences to calculate the location of the receiver.
Just thought I would mention that
This has questionable accuracy... (Score:2)
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Only beyond a certain distance. Unless these are really high powered sonar devices, they'll be transmitting via direct path. It takes a ton of power or really odd sea conditions to use convergence zone or bottom bounce modes. And if they are on opposite sides of the sonic layer depth, it probably won
Nothing New Here (Score:5, Interesting)
Been there, done that. Only difference is we didn't have GPS, only LORAN. You don't need GPS, you just need a sonar transponder whose location is well-known.
1977, aboard RV Melville (Scripps IO). We drop 3 sonobuoy transponders to the ocean floor in a large triangle (few kilometers per side). We know the approximate locations only, since they were after all dropped. Ship sails around doing research and pinging away; record round trip times to each transponder; invert large number of observations to solve for locations of each transponder relative to each other; within a day we know the relative locations accurate to within a few meters (maybe better, I don't recall); meanwhile ship is recording LORAN locations; the LORAN locations are cross-correlated with the relative transponder locations (which are more accurate); net result is that transponder coordinates now have a geographic reference (xy to lat-long).
Two issues with the GPS version: (1) you need to anchor to ocean bottom and have antenna at surface, therefore you need a lot of cable/wire; (2) the surface GPS (antenna) position is NOT the same as the transponder, since the cable is certainly not going to be perfectly vertical. Maybe you don't need to anchor it, just let it drift, then #1 doesn't matter.
Someone said this sounds eminently patentable. No, I don't think so!
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Or am I missing something about the purpose of prior art in the patent process?
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According to TFA, the base station is only at a "known GPS position". It presumably doesn't need an antenna; they just have to know where it is when they install it, and bolt it to the floor so that it doesn't move.
So it seems to me that you could delete the word "GPS" from this article and everything would still make perfect sense...
(since you say it's been done before, it's easy to see a parallel with software patents too. Software patent: "We're going to do this thing that everyone does ... on the int
Where's the "GPS"? (Score:2, Insightful)
Unless the base station is 1) going to move; 2) close enough to the surface to receive GPS signals; and 3) powerful enough in transmission/reception to communicate with submarines, I'm just not sure what the "GPS"
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Just another case of somebody calling something "GPS" with no clue what it is they are actually saying.
Prior art (Score:2)
Nothing to do with GPS (Score:5, Interesting)
This is an underwater positioning system using acoustic ranging from a prepositioned devices on the sea floor which has an accurate position. The obvious question is how do you get the position of the base station. This could possibly be done with GPS using a sea surface GPS based bouy, but there is no specifics on this.
Remember, GPS is a PASSIVE system. Nothing is sent to the satellite.
--keith
Will it ever see the light of day? (Score:2)
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Also, the Magician is here.
This isn't patented....summary wrong (Score:3, Informative)
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Hmm. There needs to be a special moderation for 'most helpful comment'.
So now... (Score:2)
Run noisy, run deep? (Score:2)
Well, if you're willing to give away your position just to find your position, then this is fine. I'd like to see them solve this problem for a sub that's running silent. Since almost all subs are military, and stealthiness is important, that's the real problem. If they don't care about giving away their position, they might as well raise their tethered antenna package above the water-line. That would be a lot less expensi... oh... wait... it's the military. Yes. Let's order this system right now. Be
Interesting but underwater GPS is not entirely new (Score:3, Interesting)
However (and without disregarding the significance of this system), GPS systems designed for use underwater that work in a similar way have been in use by divers and submarines for years, the exception being they rely on a buoy floating above to get it's position from GPS (and then, I believe, calculate the depth/angle from the buoy - which itself is able to get it's own position using GPS for a fairly accurate reading that is trustworthy).
It seems possible even a small buoy floated - even a small one designed to be very difficult to detect - could in theory give away a that a sub was in the area, if it was spotted during the presumably brief period during which it was being floated to take a reading. However, I'm inclined to think the likelyhood of that being a real problem is fairly small and it's not worth giving up the convenience of being able to do that - not forgetting the same approach also allows you to fit a receiver to it that is able to perform other functions like receiving a high bandwith data transmission.
The alternative approach that would be required by the system described in this parent would seem to involve the navy having to go around planting somewhat less transient transmitters on the ocean wherever they are operating in the world - which seems like even more of a giveaway. It also seems they will in any case need to take a reading from the surface before they plant the underwater base station, so while once established in a warzone it could be quite useful for the period the submarine was engaged in operations, you'd need to go and plant it the area in the first place, and presumably it would be fairly easy for the enemy to find and disable - or even just move it and really cause trouble...
Though I don't know what the range is, perhaps it could remain well out of harms way - from a brief reading it seems to outline one method that works over a not-so-useful 10 km, but mentions another that apparently gives accurate readings over thousands of km.
So while it's a neat idea, current technology (float a buoy with a small GPS receiver in it every now and then, maybe do a data transmission at the same time - and have the ability to that from anywhere in the world without having a base station already set up in the area) doesn't seem in need of a pressing replacement.
I should add while I know commercial industry does this (and it's used by divers), but I don't know if military submarines actually use this approach, though I can't see any unsurmountable justification that would prevent them from doing so.
Underwear GPS?? (Score:2)
Say what? (Score:2)
Since when do you need to get a signal TO the satellites? (The GPS ground control segment excluded, of course.) Obvious errors and poorly-written summaries aside, though, the real question would be how it performs with real-world acoustic propagation. How does it deal with reflections and refractions from obstacles, thermoclines, the surface, and the ocean floor?
What does this system have to do with GPS? (Score:3, Interesting)
As for military subs not wanting to give their possition away. Yes of course they would not use this. I suspect the best use of this would be for non-millitary scientific or salvage subs.
One way to make a sonar based system that would be require the sub to emit signals is to have each bouy send it's location and the exact time. Subs could passively listen to this an deduce their position. This is exactly how GPS currently works with pasive radio recievers
Another way for a sub to directly use GPS that might even work for the military would be to place a GPS antenna in a small float and release the float tethered to a long wire.
This can't be very accurate... (Score:2)
Furthermore you can't presume the water temperature is constantly the same as the temperature of that measured outside the sub, as the temperature of the sea is not constant and the sea has transient thermal layers, which themselves reflect sound at the boundaries.
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The boundary reflections are kind of interesting - if you have a sharp enough sonic layer depth, sound that gets through the layer can be trapped in a "channel" formed by the sonic layer depth on the
Brilliant! (Score:2)
If (manned) submarines don't care about their location that can just surface to antenna depth and use the (*&^^## GPS.
GPS is the correct acronym (Score:2)
Anyway, I can't wait for "Tom, Tom, bring me to Atlantis."
Submarines? (Score:5, Funny)
Signal path backwards in summary (Score:2)
The signal goes the other way...FROM satellite TO surface.
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Not new? (Score:2)
This sounds like a basic surveying technique: nail down one or more reference locations, then to locate any spot on the site shoot the reference points from it. If all you've got is a station that can tell you azimuth and inclination, you need to shoot two reference points and basic trigonometry gives you your exact location. Add in range and you only need one reference point (but two are usually used for error-checking). I was taught this way back in community college, including the use of GPS stations as
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Re:GPS is passive (Score:5, Interesting)
Unlike what another poster stated regarding cell phones, the tracker devices we used did all the GPS processing on-board, so what was sent via UDP was either a NMEA string (easily parsed) or some simple proprietary binary format. We would do further corrections at the server to account for various map books and which USGS survey data they were based off of.
Anyway, the problem we has was the truck drivers and their misconception of how GPS worked. Many of the more paranoid truck drivers (and there were a lot of them) were absolutely convinced that we were beaming personal data about the drivers themselves to GPS satellites, forwarding it to who knows where. Trying to explain to these folks that GPS doesn't work that way only resulted in angry confrontations. When I started working on a badging project so that our client could further track the comings-and-goings of the drivers, the hostility and resistance reached alarming levels, to the point where I almost couldn't get work done.
Then again, the whole reason for the software's existence in the first place was to provide documentary proof of the misconduct of drivers. Things like guys taking half-hour naps in their trucks after finishing a job site, or over-slumping their load of concrete so they can sell some excess concrete to a buddy finishing his driveway... We implemented autmated job-site entry and exit discovery because we found that giving drivers a set of pushbuttons to signal when they were starting or stopping a job was just a recipe for abuse. (Funny enough, we kept the pushbuttons to see just how big the discrepancies were between when drivers said they were working and when the GPS claimed they were working. It was eye-opening.)
The drivers were unionized in most cases, so a high standard of proof had to be met. I'm sure that contributed to the air of hostility. But it's also true that many drivers were using fake credentials (many being undocumented immigrants), so the paranoia over a potential loss of privacy and transmission of personal data to a "big bird in the sky" wasn't just because people were worried about getting caught napping on company time.
Not mentioning the names of any companies (nor any specific geographic place names) to avoid legal hassles.
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What I want to know is: have they taken into account that due to plate tectonics, the sea floor spreads? "Anchoring" anything to the sea floor guarantees it will move, although certainly a lot slower than a satellite whirling through space.
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