Ground-Based GPS Mimic Is Inch Perfect 140
holy_calamity writes "For several years the U.S. Air Force has used WiFi-router-sized boxes on a New Mexico missile range to create a GPS-like service to track munitions to the nearest inch. Now the Australian company behind the technology is rolling it out for civilians. One gold mine is already using the tech and specifications are being released so that GPS receiver manufacturers can adopt the technology. Locata hopes that construction sites, factories and city governments will all want to install their own high accuracy 'location hotspots.'"
Where's the First Post? (Score:1)
Ought to be around here somewhere?
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You'll need to unplug the router and plug it back in first.
So they reinvented LORAN? (Score:3)
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that is also because it was meant to be used on scales that involved the curvature of the earth.. not where are my keys..
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In an open cavern, perhaps. In a much more typical non-straight tunnel with pipework, moving objects, intermittent "rooms" with "pillar and stall" workings ... I suspect that you'd need to spend so much time installing and calibrating equipment that you'd be as well off sending your existing surveying team around with modern surveying equipment like theodolites, LIDAR scanners, tape measures, computerised data acquisition and GIS.
Re:Hasn't this already been done? (Score:4, Informative)
There are several solutions available currently that offer 1" or better absolute accuracy off of GPS signals. They all function by resolving the issue that GPS is precise, but not accurate. By positioning themselves at a known position in space, they calculate the offset from what GPS is telling them, and broadcast that to the nearby area. They end up being much cheaper as all you need is a good GPS receiver.
This solution instead requires accurate local time references, and as such is going to be considerably more expensive. The advantage of this system is that GPS has an incredibly weak signal. It requires line-of-sight, and even trees will block a signal. If inside a building, or down in a quarry, you are likely to not receive enough signals to get an accurate position lock. This uses local transmitters at high power to allow them to operate in less advantageous terrain.
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There's a few companies doing Loran/GPS-like tracking of police radio transmissions based on time of signal receipt time at various antennae. Accuracy varies with precision of time signal, availability of multiple receivers, etc.
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"Time Difference Of Arrival". It relies on the fact that radio waves move at the speed of light, which is actually pretty slow. You can easily detect the difference in phase between the signal received by two aerials, and turn this into useful direction information.
You can roll your own TDOA with simple parts available in your local electronics shop - take a look here [archive.org] for a "Whistling Dipole" design that switches between two aerials to determine phase.
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WWV time is almost everywhere, and free. A WWV receiver is a simple circuit.
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A very accurate time can be determined from WWV by synchronizing with the carrier frequency. The 20MHz (example) carrier for WWV is also a calibrated reference signal that can be used to calibrate your local oscillators or clocks.
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No, it can't. Frequency != time. Besides, even frequency from the NIST stations is only good to ~1e-7, as received. With much effort, you can get to about 10e-10 in a month. You can do a couple orders of magnitude better with a GPSDO.
Why was the above wrong guess marked informative? (Score:2)
That doesn't help where you can't get GPS - which is what this thing is for in the first place! It's for indoors, undergound etc.
No it doesn't. If the article gave you that incorrect impression there is another on the website of Australia's ABC Science Show from a program several months ago.
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That doesn't help where you can't get GPS - which is what this thing is for in the first place! It's for indoors, undergound etc.
No it doesn't. If the article gave you that incorrect impression there is another on the website of Australia's ABC Science Show from a program several months ago.
Such as underground where GPS signals do not go!
Because I get lost walking from oneside of the bomb shelter to the other all the time.
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Similar to previous systems of yesteryear (Score:2)
I vaguely remember they still had PDP-8's still in storage as replacement parts
Re:Similar to previous systems of yesteryear (Score:5, Informative)
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I think I remember reading that Steve Gibson of GRC purchase a handful or so.
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They already have that, it's called painting lines on the floor or installing rails.
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Henry Ford's adoption of the assembly line is even better for robot-enabled productivity than it is for human workers.
improved cellphone location? (Score:1)
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It already is. It's how TDoA cell phone location works -- the cell towers themselves are the base stations.
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Technically, WLAN location isn't triangulation - it's actually done with circles. You get signal strength, but not generally much in the way of a direction (well, there's antenna orientation patterns). The proper word for this is "trilateration".
Also, there are some ways you can improve WLAN location. For starters, you want to use a different AP deployment pattern, putting APs around the outside of the building instead of deploying them for maximum coverage. Statistical techniques, in concert with taking
aka Differential GPS (Score:1)
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Re:aka Differential GPS (Score:4, Informative)
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Sort of what I was thinking, but...
How exactly does a 2.4 GHz signal that can't penetrate a couple of sheets of drywall go thru meters of hard rock and quartz mineralization?
Current underground radio technology uses backpack-sized VLF transceivers and is designed for surface-to-subsurface communications. Subsurface-to-subsurface is currently not really available without wires, as far as I can find.
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I've worked in the DGPS industry for nearly a decade now, and I can tell you that this is not a new concept in any way. Firstly, it is true that there exist many free correction sources (e.g. WAAS in the US, EGNOS in Europe) which will allow a DGPS receiver to determine it's position to decimetre accuracy. Centimetre accuracy can be achieved with Real Time Kinematic [wikipedia.org] (RTK) corrections (either from a local base station or delivered remotely by some kind of long distance connection, e.g. GPRS). Neither opti
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Are there any free DGPS data providers? Difficult to integrate into mobile platforms like Android? I spoke with the developer of GPS Status for Android and we were discussing WAAS integration, but apparently not enough of the low-level GPS system is available to android apps.
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http://www.flepos.be/ [flepos.be] but this only covers flanders in belgium but there are similar services for the rest of belgium. The service is free but you need to register. From http://www.gps.oma.be/networks_tutorial.php [gps.oma.be] you can find links to other networks across europe but I don't know if they are free.
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As NocturnHimtatagon has alluded to, data providers only tend to cover specific areas or countries. If Andoid does not provide low enough level access to the GPS hardware to do WAAS then I doubt that you'd be able to do any form of DGPS. Typical consumer-level chips will just output NMEA data, whereas you will need access to at least the raw pseudo-range data (i.e. distance from satellite to receiver) in order to be able to apply the pseudo-range correction (PRC) values. Some provides may provider Code D
A full RTK setup can be had for *cheap*, today (Score:2)
What's `a hell of a lot cheaper'? It's possible to use a smartphone as an RTK base station [gmane.org]. That's pretty cheap--and shorter-range Wi-Fi GPS devices are even cheaper (the most expensive part in a
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No. DGPS uses a secondary signal to broadcast an offset, valid for an area a few tens of miles, with diminishing accuracy outside that. RTK combines DGPS with other trickery such as carrier phase enhancement, and a big chunk of extra processing power, to come up with a more accurate position fix.
What you are referring to is the practice of using two sufficiently different carrier frequencies from a single satellite to calculate the ionospheric delay and improve accuracy with a single receiver. This is ra
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You mean aside from being completely different?
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GPS accuracy is poor to non-existent within buildings and underground. Accurate sensor localisation is far from trivial in such environments. One hurdle is multi-path interference which renders the time-to-receive of a packet as near useless. AFAIK to achieve a high level of accuracy requires a mesh-like network and the use of multiple sensors including accelerometers with the accuracy increasing with the number of nodes in the mesh.
The CSIRO, Australia's peak science body is has been working on wireless tr [csiro.au]
Re:aka Differential GPS (Score:4, Informative)
What is new here?
Complete lack of dependency upon satellite signals?
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There is a transcipt of an interview about it here:
http://www.abc.net.au/rn/scienceshow/stories/2010/3058425.htm
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Yes of course. National internet filtering (of whatever, for whatever reason) is a great ploy to sell to nerds.
Speed, Size, and Cost (Score:1)
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An Australian company (Score:4, Funny)
Something tells me that an Australian company would not be using inches to track anything. TFA seems to agree. Our official conversion tables between metric and "ye olde worlde" include the phrase "an inch is as good as a mile", which does not bode well for its accuracy.
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Something tells me that an Australian company would not be using inches to track anything. TFA seems to agree. Our official conversion tables between metric and "ye olde worlde" include the phrase "an inch is as good as a mile", which does not bode well for its accuracy.
I think what you mean is:
"That's not an inch. THIS is an inch!"
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Inch is just embedded into the English language so get over it. If you give them 25.4 mm and they will take 1.06 Kilometers. Try singing 2.5 centimeter worm some time. And I doubt that you every put your car into low and just centimeter a long.
That being said, this is really cool. Imagine this in a mall, hotel, convention center, Hospital, or government building. Your smartphone could find you and direct you to any location. It could take you right to your hotel room, right to your meeting room, right to t
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my bad.
I don't know about Australia but I know that in the UK they still give miles per gallon and 0 to 60, and quater mile times for cars and motorcycles.
Inches and miles are just a part of the language. More examples
He will not give an inch.
It will not budge an inch.
A yard of ale,
A pint of beer.
Then metric nazis are just a bit much.
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Then metric nazis are just a bit much.
Wow, you are a bit of a joyless soul, aren't you? Yes, I know I started this metric vs imperial thread, but at least I did it with a joke. And do you really think that I do not know about sayings involving inches and miles? Hell, I used one of those sayings in my original post!
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Sorry I did probably over react. Just used to people having a snit fit when every feet or mile is used on slashdot. I started off also trying to be funny with my reference to the Song Inch worm converted to metric but I I guess took it a bit too far.
The thing is that Not a single person commented on my suggestions of how useful this could be in the consumer space. I for one love the idea for an app that would tell you how to find a conference room or even to an item on a shelf.
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Perfect to the inch or cm? (Score:2)
Doesn't the military use metric (klicks = km), along with every other industry that needs a sane measurement system?
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TFA uses metric. For some reason, the poster felt it necessary to impose his imperial will onto slashdot.
Darn those Imperialists!
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I don't know how far and deep the metric system has been adopted by the US military, but I do know when I was in the US Army(1977-1981), all of the weights and distance metrics presented to us were metric system.
Meters instead of yards, kilometers instead of miles, grams and kilograms instead of ounces and pounds; all of the basic stuff at least.
It was presented in an inexact, crude, Drill Instructor fashion though:
"A meter is a yard, a klick (US military jargon for 'kilometer') is a half mile and a 'rock t
Has existed for years, called Differential GPS (Score:1)
Its called differential GPS and is already being used all over the world. Hell its even being used on farms to guide tractors by now. It can get down to the cm level of accuracy. Not News.
http://en.wikipedia.org/wiki/Differential_GPS [wikipedia.org]
http://www.deere.com/servlet/ProdCatProduct?pNbr=GT3TAPC&tM=FR [deere.com]
Re:Has existed for years, called Differential GPS (Score:4, Informative)
Differential GPS is much different than this system.
This system requires no component of GPS except a similar receiver. That way they can use it in places no satellite signal reaches...like mines and shielded research facilities.
Re: use it in places no satellite signal reaches (Score:2)
and is commonly known in the industry as a pseudolite [wikipedia.org]...
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Hi, folks. I really appreciate the interest that seems to have been generated by our short introductory story to Tom Simonite at MIT Technology Review. It's fascinating to see “the experts” on this site shoot from the hip, with no investigation at all, and immediately assume we're some type of differential correction (no...), a reinvention of Loran (no..), some form of hybrid GPS/Inertial system (no...) or a pseudolite (ahhh HELL no!). Locata is a disruption to the industry because, plain and si
Not differential GPS and works where GPS doesn't (Score:2)
http://www.abc.net.au/rn/scienceshow/stories/2010/3058425.htm
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This is basically what Google is doing... (Score:2)
with WiFi APs/Cell Towers/MAC addresses.
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Military Intelligence (Score:1)
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The Internet.
Your computer (Turing!).
Any form of public key encryption (the UK got it first, via Turing, but didn't bother to tell anyone else - read: we used it only for our own secure messages - until US "researchers" found it again later).
Satellites in general (GPS is only one particular use of them).
Radar (you probably have on one the back of your car to help you reverse)
Night vision.
Digital cameras (first used on spy satellites)
The list goes on. It's like those people who say "Yeah, but what actual sc
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We need 3D GPS accuracy down to the millimeter (Score:3)
Millimeter accuracy in 3 dimensions would open up a lot of possibilities for use in robotics.
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Decimeter precision with fast acquisition and several accurate fixes per second would open up a lot of possibilities too. Just think of using a GPS for street navigation - the absolute positioning is usually fine, and most most of the problems you see are either on initial startup or due to lag, especially when you change velocity in any direction.
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And motion capture (and probably a whole host of new applications my imagination is too poor to come up with. Surgery? Anatomical imaging? Real time engineering analysis of structural deformation? Radio telescope antennae deployment? Really accurate munitions delivery for "keyhole" shots, personal assassination? Automatically docking/refueling of vehicles?).
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Good encoders, referencing, inertial nav, and visual cuing can give you that accuracy.
GPS should never be relied on without a backup.
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Mandrake, you're a good officer, but your priorities are spot on save for one: whiskey.
Firefighter safety (Score:1)
Robotics? Who needs robotics...
Actually, the first thing I thought of was the ability to locate every firefighter on a fire scene; their location in three dimensions would allow for downed firefighters to be found much quicker.
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You could easily achieve this by combining the proposed system with an inertial measurement unit.
Great! (Score:3)
Now we just need to get our enemies to buy a whole bunch of these, and conveniently place them on all the nice targets we'd like to bomb.
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And BTW differential GPS is an old hat: http://en.wikipedia.org/wiki/Differential_GPS [wikipedia.org]
Yaay... =) (Score:2)
Already Exists (Score:1)
Synced to 2ns? (Score:2)
From TFA: "and all the signals are synchronized to within two nanoseconds."
Light travels about 0.6m in 2ns, so this suggests accuracy will be much less than the ~3cm accuracy claimed by the summary. (If you have lots of base stations, you can do rather better than 0.6m, but a factor of 20 would not be feasible.)
Also - I didn't notice anything in the article to support the summary's "to the nearest inch" claim. Did I just miss it, or is this from some other undisclosed source?
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Precision Time Protocol (Score:2)
Also from TFA:
Enge says it is likely that these pseudolites will rely on time signals sent over the Internet, using a new protocol that enables high accuracy.
He doesn't say, but I assume he is talking about Precision Time Protocol [wikipedia.org], which allows for sub-microsecond precision. With that, the claim of 3cm is totally realistic.
I'll agree that I'm making some assumptions since this is a shit article.
However, the main takeaway from this is the idea of using devices without an on-board atomic clock & instead using a clock that must stay in sync. It is a neat idea & might work, but I wouldn't want anyone's life to depend on it.
Geocaching made easy (Score:1)
Time for Slashdot to enter (Score:2)
The era of modernity and forget alchemist practices.
You know, metric system. Science.
location hotspots (Score:1)
Great for lost items (Score:1)
They should strive make the tech small enough to fit in a keychain, cellphone and wallet.
Infrastructure sucks (Score:2)
Any system which needs you to install additional hardware sucks. We can very well use the system planes used before GPS was deployed. INS using compasses and gyroscopes. You just need everyone to have a compass and gyroscope in their pockets. Wait everyone with an iPhone4 or a NexusS already does. Wifi based GPS enhancements are the buggy whip manufacturers of our day. Even the best and most accurate will be going out of business.
A lot of confusion - here's what they are doing (Score:1)
There is a lot of confusion among the early commenters. Some think this is a form of differential GPS, some think this is a network of WiFi devices, or a hybrid of WiFi and FM radio.
It appears to be none of the above.
It most likely is a pseudo-lite (a terrestrial device which mimics a satellite), except that it does not operate in the GPS (L1 or L2) band(s). The government, researchers, FAA and Air Force (which runs GPS) are working on real pseudolites which may run in the GPS bands. But this private com
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There are two types of DGPS. In one, you have a receiver at a known location. It basically tracks the atmospheric errors in the signal propagation, and broadcasts a set of corrections. WAIS does this at a more broad level. WAIS brings the intrinsic error down to about 2-3 meters. This first form of DGPS brings it down to a half meter or so.
The next level of DPGS, which has another fancy name that escapes me at the moment, depends on tracking the phase of the satellite signal. Lose track of the signal
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Your welcome!
What about his welcome?
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