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Patent Filed for Underwater GPS
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."
This is great!
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.
liqbase
Verify range to GPS buoy. One ping... One ping only.
Little nit pick ... GPS signals go from the satellite to the receiver not the other way around.
GPS doesn't work underwater, as the signal cannot reach the satellite from a submersible
GPS is a passive system, the device never sends a signal to the satellite. Of course that mistake is widespread, as TV and Movies always show 'GPS trackers' that do just that.
A submersible anywhere in the area sends out a sonar pulse to which the base station replies with a signal,
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.
Libertarian Leaning Political Discussion Forum.
Just another way to bombard marine life with Sonar. Can we please get out of this mentality that convinces us that using active sonar all day is a great idea?
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
But, certainly military subs have been figuring out their location for quite some time.
:-P
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
Lost at C:>. Found at C.
Umm...I think the Britons patented this during WWII and called it R-A-D-A-R
This technology, like GPS, would most likely have military as the initial customer, hence the customer that sets the design. For GPS, a completely passive system was designed so that an asset could calculate where it was without giving out information to nearby enemies that it was there.
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.
Satellite GPS is purely one-way: no signal is trying to "reach the satellite". It's a good thing that this patent covers two-way-signal underwater tracking, so that we can still set up a superior one-way underwater GPS system :)
Generally submarines, especially combat ones, don't "ping" anyway- it is too easy to trace their position if they do.
Also- it seems that in a war situation- these "base stations" would be pretty high on a target list...
It does sound like a very interesting idea though.
...are been moved 10 meters south.
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.
My sig sucks.
Seems to me that this is the kind of unique idea that deserves a patent.
Unlike most software patents.
All of a sudden, U.S. is able to know the most precise location of Russian nuclear submarines that utilize such sonars for their positioning systems. :-)
I believe every military power should use this system for their submarines, at least someone would know where's everyone. And maybe do some traffic control in congested area around Bering sea (hint: Kursk)...
I thought it was stated that high intensity sonic pulses was VERY perjuditial to marine life, causing wheels to get lost and potentially killing small fishes
Ave Maria
The majority of submarines are military submarines. The one thing military submarines don't like using? Active sonar...
do you have some kind of problem keeping your pet peeves from entering every story? you suck.
Most navigation in subs is done based on dead reckoning, using highly-detailed charts of the sea floor. At least, that's how they do it in the movies :-) And it's always the reckless captain that endangers the sub by insisting on going faster than the navigator recommends, or trying to get a little too close to that underwater mountain...
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-indicating beacons permanently installed on the seabed, but I'd doubt it.
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?
Everyone who doesn't believe that the US Navy solved this problem a few decades ago raise their hands! Like in '78 when they launched the satellites, or '79 when the Trident missile entered service....
Men will do anything to avoid stopping and asking for directions
Use your head, can't you, use your head,
You're on earth, there's no cure for that - S. Beckett
That's a new record... how did I spelt wheels for whales. :-/
Ave Maria
"GPS doesn't work underwater, as the signal cannot reach the satellite from a submersible"
:)
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
it is only after a long journey that you know the strength of the horse.
...that Slashdot journalists start reporting about patents that are, for a change, not-interesting instead of retarded?
It has advantages for that application, not least of which is a lot less computational power has to be used keeping track of where you are.
How would they stop Differing thermoclines and salinity content levels from affecting the speed of the signal sent to and from the submarine? Even a Small Delay could put it way off course... I tried to RTFA but it woudln't load..
Ad eundum quo nemo ante iit!
Given that sound waves curve in areas of different density (just like light), the receiver must accurately know the acoustic conditions and path between itself and the source else the location is suspect, no?
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!
"A base station is tethered to the sea bed at a known depth and GPS location." Why does it have to be a "GPS" location? Once the depth and location are known, why is GPS needed at all for this system? (This is a serious question -- I'm wondering if I'm missing something about the setup described.)
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" aspect is for.
-snarkbot
I'm surprised there isn't prior art on large parts of this - we've been using sonar for decades for mapping, target acquisition and whole lot of areas related to range and direction finding.
In submarine sonar, all sorts of things can affect the propagation of sound at depth, not the least of which is the thermal layer, a depth at which the water above is significantly warmer (and less dense) than the water below it. Not only can this prevent penetration of sound energy entirely, but it can also cause a very similar effect for sound that the water/air boundary causes to light. Ever stick a spoon in a glass and observe that it appears bent? Similar concept. I fail to see how a bearing indication from a fixed item at a different depth could provide any more accurate a position than the Inertial Navigation and Laser-Ring Gyros that are used today.
Basically, this has nothing whatsoever to do with the Global Positioning System. It does not use the signal from the GPS satellites. It does not use any kind of GPS receiver.
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
The real question is: Will this ever actually be deployed? The market for submarines is small, at best, and there's a lot of ocean floor to cover before this would be generally useful. Also, in wartime, it's rather easier to take out a tethered buoy, even a submerged one, than the GPS satellite system. I'd rate the as a 2 out of 3 of never happening beyond a Proof of Concept stage.
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
Or do you want the terrorists to win by stealing our underwater GPS because we didn't patent it?
...I thought so!
What will you tell your children when they ask you why we closed waterworld because the terrorists have underwater GPS so they can live underwater and destroy whole countries above the surface-of-evil???
Filing a patent application does not mean that you have "patented" something. The link in the summary takes you to a patent application publication. Patent applications typically publish 18 months after they are filed (or in this case, 18 months after the earliest application to which priority is claimed). With USPTO backlogs, it will probably be 5-7 years before anyone at the USPTO even looks at this application and "patents" this invention.
The Navy has been doing just this for many years. Using GPS (albiet in it's infancy)in October 1983 I was surveying transponder networks used for underwater navigation. There was an article about it in Aviation Week and Space Technology around that time period as well.
...I guess "underwater" is the new "on the internet" when it comes to patents.
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. Better have a a backup network too, in case the primary network goes down.
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
This seems pretty cool, as it doesn't require anything floating on the surface to be able to work.
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.
And by the way, from the summary: In the GPS the signal doesn't go from the receiver to the satellite but the other way around.
The sooner you fall behind, the more time you have to catch up.
humans perpetrating the ocean ... all your oceans belong to us!
I wonder if they military think-tanks would like it, to have a sound blasted every x seconds towards their house/bedroom?
--- I am known for the ones who want to find me on the net. Is that a privacy risk or a privilege? One might wonder..
GPS uses one-way communication, so there is never a need for a signal to reach a satellite. This is also the reason no one who operates a submersible on it's own (where it would need positioning data) would ever use this service. You would have to give away your position, and if you were willing to do that you would surface and use GPS.
If the beacon transmits periodically without you having to transmit a request, your position could still be given away. A listener near by could detect the reflection of the beacon's ping off of your sub. It would affectively be like using active sonar to detect another sub, but you get to stay quiet. In a way it'd be like the semi-active radar of the AIM-7 Sparrow missile.
Then again, you also could detect the reflection ping off other objects that weren't there before. Assuming the surrounding area would have a 'baseline' sound fingerprint, which I would guess the military would try to do.
J
I mean, I can see the benefits. You can find out where your wandering spouse is spending the night. AND people think you are happy to see them, especially if you extend the antenna.
"...as the signal cannot reach the satellite from a submersible"
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?
This system sounds like it is completely independent of GPS. The tethered bouys would have no need for GPS they would have their position set into them when they were placed on their tether and as this would never change it would not need to receive a GPS signal. So where is the tie in to GPS? OK the ship that is dropping the bouys might have a GPS aboard but it could use some other navigation system.
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.
US Subs has been doing this for years... another patent on an idea already in use...
as the speed of sound through water is not a constant, but is affected by water temperature.
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.
Take a platform who's only real reason for existing is stealth, and give it a navigation system that reveals its presence and location.
If (manned) submarines don't care about their location that can just surface to antenna depth and use the (*&^^## GPS.
Why is this being touted as an addon for GPS? It doesn't even come close to approximating the functionality of GPS ie. being able to get an accurate location anywhere on the planet. You would likely need thousands of these to get GPS like functionality. This is simply sonar based location using a known landmark. In wartime, these things would be very easy to locate and destroy or use yourself. I doubt the system can even legally be used in the majority of locations the private sector would use them, due to the Marine Mammal Protection Act.
GPS = Global Positioning System, just because the current system is something else doesn't make "underwater" not GPS. Currently many GPS recievers supplment their satalite singal with something simular to this idea: WAAS (which is just another satellite, but kinda the same idea).
Anyway, I can't wait for "Tom, Tom, bring me to Atlantis."
Your mammas flamebait.
At least they will be getting away from the "on the web" software patents.
Slashdot is kind of like Playboy; we aren't here to read the articles.
100 comments and nobody's asked whether this is a submarine patent yet? Come on, guys! You must be working or something.
I can explanate how to administrate your network. You must configurate and segmentate it, so it can computate.
Search for AUV autonomous underwater vehicle, how do these come back with seafloor data after months of collecting data? The data would be useless without a position to identify it?
We didn't send out any pings when I was on a submarine. As a matter of fact, we tried not to put any sounds into the water.
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.
Engineering is the art of compromise.
Well, the title does say "Patent Filed" rather that "is patented", or "patent approved"
So it's right in the header at least...
The signal goes the other way...FROM satellite TO surface.
Government's idea of a balanced budget: take money from the right pocket to balance...oh who am I kidding?
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.
Engineering is the art of compromise.
This is sonar navigation, using GPS to calibrate the locations of the sonar transponders.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
Relative positioning systems have been available underwater for years - you can even buy handheld ones for SCUBA... Just put the base station at the anchor and swim off and then the handset tells you how far and in what direction the base is. The only difference here is that it calculates the position relative to a location specified by the base and so displays absolute coordinates rather than relative ones.
[All Your Fish Are Belong To Us]
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 reference points (much easier than trying to shoot in your reference points based on other known reference points), close to 20 years ago, and except for the GPS addition it was an ancient technique then. I'm not even "skilled in the art", and their method is the second thing I thought of as soon as I read that it was supposed to involve locating yourself underwater. The first thing of course was simply having a good sonar reflector on the buoy and letting the sub's active sonar determine the range and bearing.
Not from a sub pinging but from the ping that is sent by a known position being blocked by another sub. I think it would still need to travel by line of sight so that you could triangulate position.
This is really infringing on my rights online; that's for sure.
"Don't lose your mind trying to set it free..."
Isn't this essentially a VOR system for subs? I mean, it's using sound instead of VHF (the V in VOR) but they could probably use an ELF signal instead (even though it'd be slower than shit rolling uphill). Then again, VOR transmits only but still it's a similar idea.
Similar issues affect GPS signals coming from the satellite. Variations in the propagation speed of the signal to the receiver due to varying atmospheric conditions in several layers of the atmosphere introduce measurement errors. That's one reason that the more satellites you can see, the better. WAAS also sends approximate correction values for the current conditions as measured by nearby stationary reference receivers.
Great, what about the fact that some sea creature seem to be suiciding themselves on the beach because of they can't stand those sonar signals ?
Did you read [0050] of the patent? Here's their basic, "original" algorithm:
% 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;
newpos.hea=0;
Yep, basic trigonometry using spherical coordinates. It would never be obvious to "practitioners of the craft".
Their other algorithm is adapted from this 30-year-old software.
HIV Crosses Species Barrier... into Muppets
A company in Fremantle (Western Australia) called Nautronix has been doing something like this for at least 4 years now. It's not as basic as simple sonar pulses; they actually modulate digital information onto the sonar signal (hence the likening to GPS). I didn't have time to read the patent application, but it would seem to me that Nautronix have prior art here.
N.B. I'm fairly sure they just (last month) got bought out by a US defence super-company (one that buys up lots of small companies to exploit they're IP), so I'm wondering if this patent application has something to do with that...
Without further comment, I think it's worth pointing out the recent case of Cetaceans v. Bush on this topic. (386 F.3d 1169 (9th Cir. 2004)) The court ruled that the world's dolphins do not have standing to sue.
Revive the Constitution.
Despite all the navigation systems available to the modern world, even to the United States Navy, we still have gaps in our knowledge of the ocean. Recently a US sub crashed into an undersea mountain! Cold War-era data on the seafloor has been declassified, but still our navigation isn't all that great.
By the way, here is a free oceanography textbook!
Revive the Constitution.
With 2 beacons with angle (and depth) information it could determine its position without knowing the speed of sound in water (time * speed = distance), since the distance between the two beacons is known.
t s.htm
u ndersea-sub-sea.asp
If additional beacons with known positions where placed then with 3 beacons the sub could also triangulate its position without angle information and without sending a ping.
Systems like this already exist:
http://citeseer.ist.psu.edu/184601.html
Using a GPS underwater exists too:
http://www.patentstorm.us/patents/6807127.html
http://www.longbeachdive.com/und-water-gps-produc
Add a modem
Sonar communication (sonar modems):
http://www.benthos.com/acoustic-telesonar-modems-
And a directional receiver (antenna)... to determine angle...
(just needs two fast enough receivers + processing a known distance apart
(think ears). probably also not new technology .
Essentially its a slight variation on sonar triangulation
It goes back to basic trig...
This isn't that new and it sounds more like patent trolling to me...
But that's just based on a few minutes of googling and some back of the envelope trig,
not the opinion of a qualified expert... and I might be wrong...
----- "Profanity is the one language that all programmers understand."
Well, we've had a similar system in place in oceanographic research for quite a long time. The original was called SOFAR, and the replacement is RAFOS. I'm not going to fill in the details, as you can easily read about it:
http://www.desertstar.com/FAQ/getattachment.php?da ta=MTZ8U3BvcnRfUmV2MkIucGRm
----- "Profanity is the one language that all programmers understand."
Hey, so he has a big appetite, that's no reason to tease him! It's his metabolism. Or autism. Something like that.
Only three things are certain; death, taxes, and apocryphal quotations - Ben Franklin.
This does not appear to have anything to do with GPS. The base station is tethered to a known position and depth, it does not need to receive GPS signals since its coordinates can be entered into the base station when it is put into operation.
Yarr girl, better you surface to get a proper fix!
Friends don't help friends install M$ junk.
Patent application: "Periscopybrowse" Mirror like apparatus that allows for viewing the internet around a corner. This can be used to view someone's terminal around the corner without being seen. The periscope is a prior invention, browsing the internet through a terminal is a prior invention, but noone has thought about browsing the internet around a corner. This allows ever for things like multi-monitors without having to have a monitor on you desk. Amazing. Patent pending ! Gimme gimme gimme.
why not just float something up to the surface from the sub with a gps unit attached to it?
I've been looking for something like this and it already exists! It's called the GIB Lite.
http://www.roperresources.com/auv/gib-lite.htm
I'm guessing this system works under assumed conditions? Would terrain affect the return signal from the station? What about points or flows of varying salination between the submarine and the station? Surely that would affect the return signal (either speeding up or slowing down) and affect the submarine's calculations as to where exactly it is.
Tom Tom says turn left at the next light and proceed 20 nautical miles to the nearest enemy sub!
Got Code?
the story was titled "... Underwear GPS". Yep, I keep loosin' those pesky buggers.
oh, well, it would be no surprise that such a trivial idea got patented, if it were for software, but that's the first time I see such a trivial patent for some field else.
Do not. Touch. Down.
I couldn't RTFA, it seems slashdotted, but this is basically a buoy that transmit its position and the direction of the signal from the submarine.
Since the buoy is fixed (I assume), there is no need for it to receive GPS signals, since it knows its position. This system is more like a VOR equivalent for submarines instead of planes (using sound instead of radio). The only thing in common with GPS is that it's a navigation device and some parts of the algorithm used.
If I were on a military sub I wouldn't use it, though. Using that system requires emitting a sonar pulse that would reveal the sub's location to hostiles. I'd do it just like the real GPS does, with the buoy transmitting timestamps and positions and let the computers on board sort everything out passively. Then again, inertial systems can't be that bad if they are being used, so maybe the whole system is not worth implementing.
GPG 0x1B479C78
Finally, a way to keep track of the positions of all of my sharks with lasers on their heads!
There's no way the Navy would allow active sonar all over the place. That would give away the positions of all of our subs, I would think. All an enemy sub would have to do is sit in the shadow of the sonar and listen for spurious reflections. How nice to have active sonar that doesn't give away your position! Of course, you can argue it goes both ways, but submarine warfare isn't about a fair fight. I'm sure the US is happy enough with its subs to be willing to take its chances without active sonar all over the place.
Um... while I can understand the concept for a localized installation, GPS typically needs a line to the sky to work. Won't the irregularities on the sea bed versus the relative openness of open space necessitate the installation of a HUGE number of such floating bouys, in order that this become a truly global system? IMO, without direct line of sight, figuring out via echolocation of pings without this, while taking into account accoustic reflecting, refraction, etc... is an extremely difficult proposition.
This is not a GPS repeater system at all. What this appears to be is a underwater application of common aircraft instrument landing system, or vortac/tacan stations.
Common runway ILS gives you a very exact radius and elevation angle...if only in one direction.
VORTAC/TACAN stations provide precise radii from starting point, and TACAN adds the elevation to the data for precise location....
Think about it, navigation in all three dimensions...we've been doing it for years. This is the same systems only placed under water.
One can purchase for moderate costs a gps repeater system...so that aircraft nav systems can have a fix -before- leaving the hanger. Not really useful for navigation purposes, but it does allow maintenance work and checks to be done on the nav systems while inside a metal building. This, however, is not anything like GPS...it may locate you underwater...but it isn't direct GPS. Computers could potentially take a known location and the 'pinged' location data and plot the difference/resulting position...but it is not pure GPS.
Who is this that even the wind and the waves obey Him? Surely this computer must submit also!
The Chinese have demonstrated beyond all doubt that they could locate a satellite and knock it out of the sky. Remembering this fact, exactly how long would it take for any enemy to locate these pingers and blow them up? Pork-barrel project of the first water! Why is the American public so apathetic that it allows hard-earned tax dollars to be splurged on this sort of crap?
Time for another Revolution?
No need to anchor. We use dynamic positioning along with HiPAP and APOS to track our ROV's position.
OK, this isn't really GPS. It is more like RNAV that is used by planes. I.e. A VHF navaid broadcasts a signal and a receiver measures the signal and uses the Navaids known position to calculate the vector to the receiver thus providing a position estimate. Not saying this isn't cool, but why is GPS even mentioned? The beacon on the ocean floor could simply be surveyed, much like GPS datums, and it's position would just be known. Then build a navigation database, much like the airplanes use, that subs could use.
no patent forrrrr you.
"repeater" stations have been in use since the dawn of radio, that part is in the public domain.
marker buoys have been in use by divers since the days of the subminiature tube, that part is in the public domain.
calculating position by reference from a last known point is in the public domain, sailors have been doing that since they could plot a star position in the 15th or 16th century.
what is new here?
if this is supposed to be a new economy, how come they still want my old fashioned money?
I think you are thinking of diesel subs running silent. Nuclear subs are actually pretty noisy by comparison. Reactor noise, and all.
Then you can detect the pattern difference if it is at the same level.
http://www.rense.com/general79/wdx1.htm
Do they have a plan for updating the positions stored for these stations as the plates they are on move two or three inches every year?
"Other than that, Mrs. Lincoln, how was the play?"
Now every submarine will tell others their position by the positioning sonar!
War will end quickly! Whale will extinct more quickly!
Damn it. I would rather use a long wire and a waterproof GPS device to receive GPS signal from surface to do the same thing
See for example http://www.ixsea.com/pdf/2006-09-gaps.pdf (as well as other apparatus at http://www.ixsea.com/en/products/002.001.001/subse a-navigation-positioning.html). This device works exactly the way it is described in this patent.