Birbla

Join the discussion

Write your take first — we'll ask for email only when you're ready to publish.

Sign in
  • Hacker News
  • Ah yes, 33 feet, the suspiciously not round number which suspiciously translates to almost exactly 10 meters. Just use meters, lol.
    by NietTim
  • It's strange that agriculture incurred so large losses, I would expect precision farming to rely on RTK (with relatively close reference base station at a fixed location).

    The article doesn't mention, but how immune or affected were base station corrected RTK positioning systems?

    It sounds a lot less dramatic if we can absorb such events with RTK base stations.

    That does add the extra dependency of network links to get the RTK correction stream, unless some day it is standardized to be broadcast locally on FM or so.

    by DoctorOetker
  • I recall that event. It wasn’t the error that was the problem, it was that the units weren’t able to get fixes amid the solar storm, rendering the machines inoperable; save driving by hand, of course, but that isn’t practical with many modern planters.
    by win311fwg
  • Is this considered "outside-in" GPS? That is, relying on satellites orbiting the Earth? Is there such thing as "inside-out" where maybe you rely on the images of the sky above? I guess without IR or other secondary scanning technologies, that would be difficult.
    by Yhippa
  • https://en.wikipedia.org/wiki/Star_tracker

    It's old tech

    There's also the classic of dead reckoning, which is usually infeasible but modern commercial aircraft have the capability of bounded accuracy in their dead reckoning navigation for several hours at a time if needed, and if you are the US government, you can build fantastical machines to measure your own motion and dead reckon yourself to a very very tight point on the other side of the world.

    https://en.wikipedia.org/wiki/Advanced_Inertial_Reference_Sp...

    That thing still has orders of magnitude better stability than common laser ring gyros as used on those airplanes, and the same for the price tag.

    GPS was dominant because it's cheapish and high performance and easy for a lot of contexts. However, it is critically easy to jam, for physics reasons. A jamming transmitter will always be thousands of miles closer to you than the GPS satellites are. Jamming GPS is cheap and easy, so all war will involve the denial of precision GPS guidance, so we are looking into alternative guidance again.

    TERCOM as used in the Tomahawk missile existed to guide them semi-inertially back in the 80s and was functional.

    In Ukraine, various providers have developed (supposedly) ways of using commodity cameras to watch the scenery pass by under a flying drone to ground medium quality inertial systems, to allow dirt cheap, unjammable navigation over long distances. It will be interesting how this plays out.

    by mrguyorama
  • Somehow, Selective Availability returned.
    by ashleyn
  • Maybe not intentionally (at least by the U.S. Government, but the consequences are far greater now.

    Now that GPS has subsumed a large part of air navigation as more VOR and ILS approaches at non-towered airports are being left to fall into disrepair, it forces more and more aircraft operating in instrument conditions to fall back to a navigation system that may not operate to the tolerances that you need to shoot an approach to LPV minimums (which puts you close to 200 feet or so above the ground) or LNAV minimums (higher, but still pretty low to the ground). If you lose signal integrity, you abort the approach. You don't want to break out at minimums only to find that the runway is 33 feet to the left or right of the centerline when it's not a circling only approach where you're expecting it. If that field only has RNAV (GPS) approaches, you have to divert. Hopefully the alternate airport you filed has a ground based approach plate available that is authorized .

    When SA was around, we had more VORs, more VOR and ILS approaches, and while NDBs (decades old radionavigation beacon that operated on the AM band) were on their way out, they were still around.

    by Quibblingeek
  • Related:

    https://news.ycombinator.com/item?id=49500504 Cheap GPS jammers are filling the world with navigation dead zones (wsj.com) 3 days ago

    https://news.ycombinator.com/item?id=48606271 Satellite reveals immense scale of GPS signal tampering (space.com) 3 months ago

    by gm678
  • *10 metres
    by delta_p_delta_x
  • Obligatory: https://www.xkcd.com/3248/
    by blululu
  • Feet are actually great units for RF because a nanosecond is very close to a foot. Since feet has many prime factors and/or the foot-meter conversion is also easy, you can quickly get a wavelength of, say a 2GHz (6 inches), and get it in cm (15cm).

    Of course, ideally we'd ditch the silly metric system and use natural units. Then these 30 feet are a more comfortable 50M/eV. But those SI guys are really conservative and attached to confusing unit system based on fractions of the diameter of an arbitrary planet.

    by rotringlvr
  • Wouldn't RTK help mitigate this, as the base stations would also be affected by the atmospheric disturbance?
    by 1e1a
  • Yes. WAAS should also help a lot, or at least tell you that you can't get a good position.
    by entrope
  • I think so, yes. That's the main purpose of RTK
    by jplona
  • Adjacent to that, I'm a bit surprised that there hasn't been a mass rollout of assisted GNSS in large cities. Maybe not full RTK, but something more than just delivering almanac being delivered.

    Are the current GNSS solutions good enough (or too degraded?) in city jungles that there would not be any mass benefit? Too expensive to run a few base stations here and there?

    by Avamander
  • It seems worth mentioning that the last time GPS had issues like this afaik, it was due to the US utilizing 'selective availability' due to national security issues. We used it somewhat famously during the 9/11 attacks.

    Also the page 404's via archive.org, but information formerly from gps.gov can still be found here: https://archive.ph/trwOo

    Edit: The selective availability page moved to https://www.gps.gov/selective-availability

    by f1ay
  • > We used it somewhat famously during the 9/11 attacks.

    I have not been able to locate any source that backs up this claim.

    by corndoge
  • An interesting warning as Austin is blanketed by Cybercabs. I think a town full of golden driverless cars 33 feet from where they think they should be is terrifying.
    by nwbear90
  • I would be shocked if Cybercabs solely rely on GPS for positioning. I imagine they look at their surrondings, etc.
    by John7878781
  • TFA article claims: "Indeed, the solar storm of May 2024 is estimated to have cost the US agricultural industry $500 million due to disruptions in precision navigation."

    This seems hard to believe. The link provided hand waves through how it maybe could happen, and ends with an Economist just SWAGing that it could have been maybe a dollar an acre or so.

    "He estimates that affected farms lost about $1 per acre. Nationally, this equates to an estimated half-billion dollars in lost earning potential, Griffin says."

    So yeah, hard to believe was the right call. Very few farms were affected, but if we assume half of the total 900 million acres of farm land were, add 10% to get a round number, and guess it at a dollar per acre, we get the quoted big number.

    by MarkusQ
  • That’s how all “estimated damages” work. It’s all just made up by some random person who guesstimated a number then multiplied it by the maximum possible people effected, realistic or not.
    by sen
  • I'm an Amazon driver and we heavily rely on GPS for delivering. We don't just use it for navigating, we also make each delivery inside of a geofence, and the delivery location is recorded and used for future routing. When the GPS says you're a block away from where you are, you're unable to make the delivery without contacting support. I've had days where GPS problems wasted a lot of my time, so I imagine it would be expensive if it happened across an entire region. On the other hand, these kinds of disruptions are already factored into the business model and planned for, so saying it cost an industry X amount of dollars is assuming that the industry was planning for ideal conditions in the first place.
    by merryocha
  • This is exactly the sort of thing that leads to people getting reincarcerated after their electronic monitoring devices mistakenly report them leaving their homes.

    Some reporting I did on the topic a few years back: https://chicagoreader.com/news/many-on-house-arrest-in-cook-...

    by chaps
  • There's always someone who roots for the criminals
    by fhn
  • I mean, you had the chance to leave the house, compensating for the GPS error. Why didn't you take that chance?
    by amelius
  • Sounds like you could be a convict, have your gang interfere GPS on a local level but enough to have other people in the neighborhood notice, make a quick run for whatever you'd need to, and still claim plausible deniability.
    by cromka
  • Geofence monitors have buffer zones because a small GPS on someone’s ankle inside a house, potentially a high rise, isn’t going to be that precise.

    33 feet is well within the allowances IIRC. Varies by state.

    by Aurornis
  • I misread that as "people getting reincarnated" and was momentarily very confused.
    by userbinator
  • > This

    As in, GPS being off by 33 feet?

    > leads to people getting reincarcerated

    I'm reading your article and it seems to be about police coming to check and realizing that the reporting of being miles away was in error, not people getting reincarcerted because of GPS incorrectly reporting they moved ~30 feet too far? One of these is much more insane than the other.

    by dataflow