If Sandia is revealing this, they probably have a secret version that is already being loaded into cruise missiles and ICBMs. Seeing what’s happening over in Ukraine, it has to be clear to every military in the world that GPS is no longer of much practical use on its own.
New laser could cram GPS alternative into a shoebox
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Re: New laser could cram GPS alternative into a shoebox
#52We’ve had other discussions of these sort of quantum compass ideas, see https://news.ycombinator.com/item?id=40692333 for example. I can never quite wrap my head around it or figure out if they are all the same idea, or what, and what exactly the idea is. In particular, the article soften describe something that “could replace GPS.” But then they start taking about compasses, and things that sound a lot like IMUs. In…
This used to be mostly a military problem. No longer.
GPS is no longer reliable enough for civilian aerial navigation in much of eastern Europe and the Middle East.[1] "Most recently, for the one-month period from July 15 - August 15, 2024, a total of
41,000 flights experienced spoofing.
Because modern aircraft have incorporated GPS into a large number of aircraft
systems, the impact of a spoofed GPS signal has had severe and cascading
effects. These include the FMS, Hybrid IRS, the aircraft clock, GPWS, Weather
Radar, CPDLC, ADS-B and ADS-C, as well as numerous other systems."
GPS is so low power that spoofing signals now take out a large area of service.
Re: New laser could cram GPS alternative into a shoebox
#53Earlier quoted context omitted.
Nuclear arms doesn't need as much accuracy as other weapons though: when using a cruise missile or a glide bomb with a few hundreds of kilograms of explosives, you need metric precision to get the military effect, when the payload is a 100kt bomb, then 100m is accurate enough. Unlike other bombs it must absolutely be 100% resilient to any kind of spoofing though, for obvious reasons, hence GNSS is a nonstarter for th…
My point was that nuclear missile development gets a blank check and I cited the over-six-figure intertial guidance units in 80's and 90's era missiles as an example of this. I'm not sure what point you're trying to make here? Accuracy is incredibly important because you don't put a nuke somewhere to kill people; you put it there to destroy infrastructure. More specifically nuclear missile silos, and bomb shelters (w…
> you don't put a nuke somewhere to kill people; you put it there to destroy infrastructure. More specifically nuclear missile silos, and bomb shelters (well, the people inside them.)
It depends.
"Counter-force" strikes aim to destroy the ability to respond or attack with nuclear weapons, not infrastructure per se. So that's just silos, warhead storage sites, submarines in port, airfields, etc. The US is doctrinally counter-force for about half a century. This doctrine is also reflected in technological choices: lower yields and higher precision mean lower fallout, collateral damage, and fratricide when hunting for silos, but aren't that useful for city busting.
"Counter-value" strikes are pure destruction of cities and killing of people. Russia seems to have this doctrine [1]. This is a very inflexible doctrine, because you can't credibly threaten to execute a counter-value attack on the US over things that don't seem to be worth a response in kind (like a defeat in Ukraine). It's much cheaper though.
> The very latest US ICBMs are suspected of having sub-100m CEP
Apparently the precision is good enough for photos like the one on page 23 here https://www.osti.gov/servlets/purl/1557069
[1]: At least strategically. There is a hybrid strategy of targeting military-related infrastructure, which Russia seems to have adopted for less-than-strategic forces according to recent leaks https://www.ft.com/content/237e1e55-401d-4eeb-875b-03fe68f81... .
Re: New laser could cram GPS alternative into a shoebox
#54Sadly, the first applications of this will most likely be military.
This will absolutely go in missiles to handle GPS jamming and submarines where satellite signals are unavailable, yes. It'll be nice if they can get it small enough for a phone, though.
Yeah it would be awesome to finally have accurate positioning in between highrises on the phone, gps sucks for that.
Re: New laser could cram GPS alternative into a shoebox
#55So, remembering the exact location once, and then tracking all movement with almost absolute precision, thus calculating all future locations? Did I get it right?
Re: New laser could cram GPS alternative into a shoebox
#56Sadly, the first applications of this will most likely be military.
This is truism applicable to the vast majority of technologies. Space was once also a rival mother of invention. If quantum INS can soon take out more Russian ammo dumps in spectacular fashion, then bring on improvements to lasers.
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Re: New laser could cram GPS alternative into a shoebox
#57So, remembering the exact location once, and then tracking all movement with almost absolute precision, thus calculating all future locations? Did I get it right?
Basically yes. If you want to get technical about it, it's not tracking movement it's tracking acceleration, which you can then integrate twice to update position.
Re: New laser could cram GPS alternative into a shoebox
#58But like an IMU, doesn’t this need occasional calibration with a known location source?
Re: New laser could cram GPS alternative into a shoebox
#59So, remembering the exact location once, and then tracking all movement with almost absolute precision, thus calculating all future locations? Did I get it right?
Basically yes. If you want to get technical about it, it's not tracking movement it's tracking acceleration, which you can then integrate twice to update position.
Technically, acceleration is movement in an inertial system... Anyway, I was wondering for a long time, why phones/watched don't attempt to do it (at least, I never saw useful results of it). Surely it would be more useful to me than nothing, when lost in a labyrinth underground. I always assumed, that results are so horrible (close to random) that nobody even bothers. But then it doesn't tell me much if there is an accelerometer 1000 or 1M times more accurate, in a shoe-box or otherwise. Like, how often does it have to re-calibrate after all?
Are there any records of how currently available consumer devices measure up in this regard?
Re: New laser could cram GPS alternative into a shoebox
#60We’ve had other discussions of these sort of quantum compass ideas, see https://news.ycombinator.com/item?id=40692333 for example. I can never quite wrap my head around it or figure out if they are all the same idea, or what, and what exactly the idea is. In particular, the article soften describe something that “could replace GPS.” But then they start taking about compasses, and things that sound a lot like IMUs. In…
Inertial navigation can be paired with GPS (and friends), terrain recognition, etc. to keep it accurate, and it can be used to detect jamming attacks on GPS. You can even use fairly low accuracy IMUs to detect jamming attacks on GPS, so it's certainly worth using.
With enough accuracy the frequency at which an IMU needs to be recalibrated with GPS or other systems can be low enough that a ship need only do it when at port, or a plane need only do it when parked or at an airport gate. I.e., at places where differential GPS can be available and/or where location can be known statically since the location only changes due to continental drift (i.e., very slowly).