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Science Technology

Scientists Conduct First Test of a Wireless Cosmic Ray Navigation System (arstechnica.com) 36

An anonymous reader shares a report: GPS is now a mainstay of daily life, helping us with navigation, tracking, mapping, and timing across a broad spectrum of applications. But it does have a few shortcomings, most notably not being able to pass through buildings, rocks, or water. That's why Japanese researchers have developed an alternative wireless navigation system that relies on cosmic rays, or muons, instead of radio waves, according to a new paper published in the journal iScience. The team has conducted its first successful test, and the system could one day be used by search and rescue teams, for example, to guide robots underwater or to help autonomous vehicles navigate underground.

"Cosmic-ray muons fall equally across the Earth and always travel at the same speed regardless of what matter they traverse, penetrating even kilometers of rock," said co-author Hiroyuki Tanaka of Muographix at the University of Tokyo in Japan. "Now, by using muons, we have developed a new kind of GPS, which we have called the muometric positioning system (muPS), which works underground, indoors and underwater."

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Scientists Conduct First Test of a Wireless Cosmic Ray Navigation System

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  • by Larsen E Whipsnade ( 4686581 ) on Monday June 19, 2023 @01:15PM (#63615898)
    TFA wastes a lot of space talking about pyramids and then casually mentions a ground station without saying quite what it does.
    • Given the brief description mentions that they have to have ground stations I suspect it merely measures the time of flight of the handful of muons passing through both your current location and the various ground stations and then calculates your position based on those. So like GPS only you are using ground stations not satellites and muons instead of radiowaves.

      The range will be limited by the fact that the further away from the ground stations you are, and the deeper you are, the fewer the number of
      • And the muon would have to hit both detectors. Several, actually, to get a fix.

        This article is useless.
        • No - provided you have low noise detectors (easy to make with a few bits of scintillator plastic, some PMTs and a local coincidence between them) each muon only needs to hit one ground station and the detector you are carrying. The rate of cosmic muons on the Earth's surface is one per cubic centre per second roughly and it will be much less underground. Since the range is a few hundred metres it will only take the muon less than a microsecond to get from the ground station to the detector you carry. This m
      • Also, since there is presumably no way to communicate with radio waves between the ground station and your location you can only map your location afterwards when you can compare the times of hits recorded by your detector with those of the ground stations.

        You can get wireless communication between surface and some hundreds of metres underground, through wet rock. There are several techniques in use, but the one I know best is called the "MolePhone", and was developed for cave rescue use from the mid-1970s

    • Well, I, for one, plan on sticking with my wired cosmic ray navigation. I don't trust this newfangled wireless version they're talking about here.

    • Well, muography's first successful run - for some value of "successful" - was in the Great Pyramid.
  • by Geoffrey.landis ( 926948 ) on Monday June 19, 2023 @01:16PM (#63615902) Homepage

    The article doesn't really explain how the system works, but from the description, looks like it needs "ground stations" (that is, detectors at known fixed locations) in place to be able to navigate, and these ground stations need to be able to communicate with the navigation system.

    Since they can communicate, the only reason I can think of that this is better than just having the "ground stations" send timing signals directly is muons have less variable speed than radio signals when traversing through rock (with a refractive index n>>1).

    • I don't think the ground stations need to transmit RF at all. They would be able to send their readings with a timestamp over a data link by any means necessary. For a boring project, a tether could be the data link to an outside cellular transmitter. The device that needs its location would take its own cosmic ray readings and compare it to known emissions and timestamps at each ground station to triangulate itself.

      A signal that would go through the core of the planet would have some pretty insane power

  • by MagicMike ( 7992 ) on Monday June 19, 2023 @01:25PM (#63615924) Homepage

    Ars Technica is just a summarizer like Slashdot.

    What has happened, slashdot readers? So lazy - back in my day, you whippersnappers - we'd see a link to a scientific journal PDF and *click* the thing so we could learn stuff.

    Instead the first two comments are just "how does it work"

    https://www.cell.com/iscience/... [cell.com]

    Muons don't arrive all the time (unlike GPS signals) so you have to kind of get lucky that you detect enough in the right spots, but if you do, with some math and knowledge of how the particles work, you can locate the receiver apparently.

    Cool trick

    Can it be jammed ? Hmmm

    • Back in the day scientific journals hated a link to their publication on /. because it invariably killed their web site.

    • msmash etc happened and despite it being repeatedly pointed out are obviously proud of turning Slashdot to shit. Either they own a piece or are doing this for nefarious reasons unrelated to revenue, for the original Slashdot was tremendously influential.

    • Can it be jammed ? Hmmm

      Presently, you need a supercollider to generate them which makes jamming unlikely in this century.
      However, DARPA wants to make a portable muon generator, you know... for reasons. https://www.theregister.com/20... [theregister.com]

      • No, you do not need a "super collider".
        You can do it with some spare equipment from a junk yard.

        Myon catalyzed cold fusion is a thing since the 1950s ... (hm, why do americans write it Muon? Don't you have a Y key on your kea-u-board anymore?)

  • ...submarines?

  • by cstacy ( 534252 ) on Monday June 19, 2023 @01:43PM (#63615958)

    I assume they use the muons to modulate a simple subspace differential pulse, and read back the quantum fissure parameters.

  • by OneOfMany07 ( 4921667 ) on Monday June 19, 2023 @01:53PM (#63615984)

    Their explanation image has detectors above the goal location. Muons come from space and can pass through matter. Their explanation made it seem REALLY similar to GPS, with a set of distances being measured between many known points and an unknown point.

    The earlier version needed a cable between the unknown location and the other detectors. It got them down to centimeter accuracy, but limited a lot about their system. This version removed those cables but would have worse accuracy. They suggested it only be used for slow moving and inaccurate situations.

    Wish they had a legend for their picture. I think the yellow/orange dots are all detectors. So there is a 3D grid of them spread out above the unknown location. I think the range of detection is small. Meaning the muons only get seen when they're exactly at a certain spot. With enough of those around and a bit of fast math you'd get a set of points that lead to your object/goal.

    • by crunchygranola ( 1954152 ) on Monday June 19, 2023 @03:55PM (#63616338)

      Both the TFA and the original paper are terribly written and lack a clear explanation of the principle of operation, which if they wrote it would be a single paragraph, maybe four or five sentences, and should be in the original papers summary.

      It appears to work this way.

      There are is a fixed detector array and a movable single detector separated vertically, and which are connected by a data link. When a muon passes through both an array sensor and the movable sensor this event is detected by the nearly simultaneous, but slightly lagged coincidental detection in the movable sensor. The time difference gives the path length resolution. Multiple detections build a position solution based on the known geometry of the probe array.

      That is four sentences.

      • Multiple detections build a position solution based on the known geometry of the probe array.

        Except that, for your generic task of "navigation", one thing you definitely do not know is the geometrical relationship between your movable station and your reference stations. Because if you did know that, you wouldn't have a navigation problem.

        That said, your explanation does make it reasonably clear how it works. Thanks.

        You can improve the knowledge of the location of the mobile detector by successive approxi

  • affect them somehow? I mean it's not likely going to affect anyone else trying to measure them, but right there in the article/s headline it says they aren't affected by even kilometers of rock. What's in the detector that can measure/affect them that kilometers of rock can't? (looking at you, Heisenberg)

    • cosmic rays have a tendency to heavily damage and/or ionize things it passes through (at a very small scale, of course). You can detect the ionization or measure the Cherenkov radiation.

      When looking for a gunshot wound, you look for the gaping hole, not the bullet.

  • ....but that sort of feels unjammable, no?

  • Could this system be used a few thousand meters (3,800m) under the surface of the ocean?

    • Yes, but only if you have multiple "ground stations" at fixed (and known) locations which can communicate with the object you're trying to locate.

      • Nope.
        Has nothing to do with ground stations.

        No idea where this myth comes from, you are not the only one mentioning ground stations.

        The whole article does not mention anything about ground stations and the big intro: âoeNow, by using muons, we have developed a new kind of GPS, which we have called the muometric positioning system (muPS), which works underground, indoors and underwater.â makes pretty clear that you do not need ground stations. What would they be good for?

        The device in your pocket

        • Nope. Has nothing to do with ground stations. No idea where this myth comes from, you are not the only one mentioning ground stations.The whole article does not mention anything about ground stations

          Open the article we're discussing [arstechnica.com] and scroll down to the first paragraph following the picture. The paragraph states:

          "The team's earlier iterations connected the receiver to the ground station with a wire, which limited movement considerably. This new version—the muometric wireless navigation system, or MuWNS—is, as the name makes clear, completely wireless and uses high-precision quartz clocks to synchronize the ground stations with the receiver.Taken together, the reference stations and synch

    • At ground (well, sea) level, your particle has passed through about 50km of air (at various pressures) which is composed of nuclei mostly of mass 12-18. In terms of mass, that's fairly closely similar to 10m of liquid water (composed mostly (by mass) of nuclei of mass 16).

      Say the flux at the top of the atmosphere is 1 unit (particle per microsecond per square metre of detector ; whatever unit), and the flux at ground (sea) level is 0.9 units - so about 10% absopbtion through the atmosphere. Assuming the at

  • I wonder if this will also block jamming?

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