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The Military Wireless Networking Hardware

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.'"
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Ground-Based GPS Mimic Is Inch Perfect

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  • Ought to be around here somewhere?

  • Wasn't this like a system they used before GPS that was still in minimal use until recently?
    I vaguely remember they still had PDP-8's still in storage as replacement parts
  • I wonder how long it will take before this becomes available for use in cellphones to improve the accuracy of tracking. It would make services like 'find my iphone' even better, but would also enable government agencies and stalkers to get an even better lock on those they're tracking.
    • I wonder how long it will take before this becomes available for use in cellphones to improve the accuracy of tracking.

      It already is. It's how TDoA cell phone location works -- the cell towers themselves are the base stations.

    • How about you drop the extra "wifi-router sized boxes" and do microlocation with actual wifi routers and pre-existing security camera feeds? []
  • Which has been developed and used for the last 20 years. What is new here? []
    • smaller and cheaper allowing rapid temporary deployment for project sites?
    • DGPS is all about using the fact that error in a normal satellite GPS signal is relatively constant in one location on Earth - the ground based transmitters just tell the DGPS receiver what that error is in your specific location. This sounds like they are using actual ground-based GPS transmitters, thereby removing the calculation of where the satellite is in the first place, to improve accuracy.
    • AFAIK DGPS uses fixed nodes to broadcast error in the satellite signal, while this system used fixed nodes to act like satellites. So this system can work with zero signal from satellite.
    • by wagnerrp ( 1305589 ) on Monday August 01, 2011 @10:45PM (#36955514)
      No. Differential GPS uses a local transmitter to provide local offset to the GPS position. This uses local transmitters as the time source, to allow it to operate in places the GPS signals will not reach.
      • Such as ... in a gold mine.
        • by chill ( 34294 )

          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.

      • 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 [] (RTK) corrections (either from a local base station or delivered remotely by some kind of long distance connection, e.g. GPRS). Neither opti

        • 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.

          • [] 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 [] you can find links to other networks across europe but I don't know if they are free.

          • 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

        • Centimetre accuracy can be achieved with Real Time Kinematic (RTK) corrections (either from a local base station or delivered remotely by some kind of long distance connection, e.g. GPRS). Neither option is free, but subscribing to a correction provider is a hell of a lot cheaper than buying your own base station.

          What's `a hell of a lot cheaper'? It's possible to use a smartphone as an RTK base station []. That's pretty cheap--and shorter-range Wi-Fi GPS devices are even cheaper (the most expensive part in a

    • You mean aside from being completely different?

    • 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 []

    • by JoeMerchant ( 803320 ) on Monday August 01, 2011 @11:19PM (#36955690)

      What is new here?

      Complete lack of dependency upon satellite signals?

      • by dbIII ( 701233 )
        And also no requirement for the expensive accurate time sources that are in the satellites.
        There is a transcipt of an interview about it here:
  • TFA doesn't go into details, but I'm imagining a replacement for mo-cap and wiimote/kinect if it updates quickly enough, is small enough, and cheap.
    • by duk242 ( 1412949 )
      That's exactly what I'm thinking it would be good for. You could do some awesome VR/MoCap stuff with this :D
  • by Gadget_Guy ( 627405 ) * on Monday August 01, 2011 @10:23PM (#36955328)

    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.

    • 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!"

    • by LWATCDR ( 28044 )

      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

  • Doesn't the military use metric (klicks = km), along with every other industry that needs a sane measurement system?

    • by petman ( 619526 )
      TFA uses metric. For some reason, the poster felt it necessary to impose his imperial will onto slashdot.
      • by Anonymous Coward

        TFA uses metric. For some reason, the poster felt it necessary to impose his imperial will onto slashdot.

        Darn those Imperialists!

    • by rts008 ( 812749 )

      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

  • 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. [] []

  • with WiFi APs/Cell Towers/MAC addresses.

    • Not quite. Google is using the Received Signal Strength from WiFi access points. Here, Locata uses Time-of-Arrival measurements, obtained through GPS-like signal processing. This kind of techniques (based on correlation of a spread spectrum signal) is much more accurate than what Google uses, although I doubt it reaches inch accuracy.
  • Can anyone name any other technologies that were originally developed by the military which are in common use by private citizens today?
    • by PPH ( 736903 )
      Emergency Medical Services.
    • by jsm18 ( 1317959 )
    • The INTERNET
    • by ledow ( 319597 )

      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

  • by sp3d2orbit ( 81173 ) on Monday August 01, 2011 @10:54PM (#36955558)

    Millimeter accuracy in 3 dimensions would open up a lot of possibilities for use in robotics.

    • 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.

    • 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?).

    • by xtal ( 49134 )

      Good encoders, referencing, inertial nav, and visual cuing can give you that accuracy.

      GPS should never be relied on without a backup.

    • What we really need is food, water and air, all of which should be clean.
      • by Pope ( 17780 )

        Mandrake, you're a good officer, but your priorities are spot on save for one: whiskey.

    • 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.

    • by Timmmm ( 636430 )

      You could easily achieve this by combining the proposed system with an inertial measurement unit.

  • by mrxak ( 727974 ) on Monday August 01, 2011 @11:00PM (#36955594)

    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.

  • Just need to shrink 'em to keyring size and I'll be able to find my keys! ;)
  • This has existed for years, and heaps of companies use it. from rio tinto automation to fork lifts and kalmars for product tracking. Sigh its paid advertising - a press release/paid feature. [] [] [] []
  • 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?

    • The 3cm mentioned in the summary = ~1in which is probably where they got the idea. Although anyone measuring something useful probably isn't using inches anyway.
    • 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 [], 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.

  • With that kind of accuracy, it's almost like cheating. I want it now!
  • The era of modernity and forget alchemist practices.
    You know, metric system. Science.

  • No long time there will full of location hotspots.
  • They should strive make the tech small enough to fit in a keychain, cellphone and wallet.

  • 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.

  • 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

    • 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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