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New laser could cram GPS alternative into a shoebox

spectrum.ieee.org

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Re: New laser could cram GPS alternative into a shoebox

#81

Post by jandrewrogers »

ttul wrote: post #51

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.

US military systems have always been based primarily on inertial guidance as a matter of policy. They may take optional GPS corrections for small improvements in precision but they don't rely on them. GPS was never really designed to be a navigation system, even though you can use it for that; the military designed it to be a measurement system. The Soviets could have destroyed it the day it was built, it was strictly a peacetime tool.

Also, what gets exported to Ukraine is intentionally downgraded in many cases, at least from the US side. Much of what they receive was state-of-the-art circa 1990s or earlier.

Re: New laser could cram GPS alternative into a shoebox

#82

Post by minetest2048 »

cyberax wrote: post #78

Another obvious idea: use mega-constellations. GPS signals can't be signed because the signal bandwidth is limited, a digital signature is going to take hours to get transmitted. But by using something like a Starlink satellite, it's possible to transmit digitally signed timing packets that can't be spoofed.

Galileo open signals are signed: https://www.gsc-europa.eu/galileo/services/galileo-open-serv... and it have the same data throughput as GPS L1

Re: New laser could cram GPS alternative into a shoebox

#83

Post by MichaelZuo »

aftbit wrote: post #69
MichaelZuo wrote: post #62

Earlier quoted context omitted.

There are many frequent flyers travelling on routes going through those regions, dozens of times each in the last year. And they haven’t reported any noticeable issues caused by GPS spoofing, at least not that I’ve heard of. So I’d be surprised if modern planes are designed such that the loss of GPS for an hour or two would cause issues severe enough to be noticed by even seasoned travellers.

Not to be a jerk, but you would be wrong. GPS spoofing is a growing problem in commercial aviation. So far it has not led to any fatalities, but it has led to a significant number of system malfunctions which degrade the safety features available to pilots. One example that made the rounds on social media a few months back was a crew flying above 30,000 ft receiving "Terrain - Pull Up!" advisories. They ignored them,…

Pilots can be instructed to ignore GPS related warnings and not trust GPS based systems for the one or two hour duration while they are transiting the jammed airspace.

Better yet they can be disabled temporarily since presumably the same proof can be shown to the relevant regulators, airline HQ, etc…

They aren’t automatons that must obey every single system installed in the plane regardless of how absurd the outputs are.

Re: New laser could cram GPS alternative into a shoebox

#84

Post by askvictor »

MichaelZuo wrote: post #83
aftbit wrote: post #69

Earlier quoted context omitted.

Not to be a jerk, but you would be wrong. GPS spoofing is a growing problem in commercial aviation. So far it has not led to any fatalities, but it has led to a significant number of system malfunctions which degrade the safety features available to pilots. One example that made the rounds on social media a few months back was a crew flying above 30,000 ft receiving "Terrain - Pull Up!" advisories. They ignored them,…

Pilots can be instructed to ignore GPS related warnings and not trust GPS based systems for the one or two hour duration while they are transiting the jammed airspace. Better yet they can be disabled temporarily since presumably the same proof can be shown to the relevant regulators, airline HQ, etc… They aren’t automatons that must obey every single system installed in the plane regardless of how absurd the outputs…

Yeah, I would guess that a spoofed signal wouldn't be that hard to detect - though you'd presumably need the GPS receiver to be capable of this. A spoofed signal would have to be stronger than the real thing in order to drown it out, no? So as a first guess - if a signal is unreasonably strong, the signal is probably spoofed, so warn the operator.

Re: New laser could cram GPS alternative into a shoebox

#85

Post by dgroshev »

aguaviva wrote: post #80
dgroshev wrote: post #70

Earlier quoted context omitted.

I don't think there is any conceivable scenario in which Russia using nuclear weapons would lead to anything resembling "World War", except Russia launching a counter-value strike against continental US, which is just not happening. A high-altitude detonation is not a "World War". Russia is a China's client state at this point, and China is very interested in keeping nukes taboo. They are so worried their own army is…

A high-altitude detonation is not a "World War" Obviously (as in very obviously) this wouldn't be the big one in itself, but an entirely possible provocation that could shove things in that direction. China is a significant inhibiting factor, but one factor among many. "Client state" is a caricature, the relationship is more complex than that. Also, no one is "pushing Russia's back against the wall" in Ukraine, there…

> an entirely possible provocation that could shove things in that direction

How? What plausible pathway do you see between Russia exploding a nuke over Novaya Zemlya and their suicide by American nuclear response?

> A major shift in the ground situation Ukraine's favor (effectively signaling an eventual Russian defeat) could do the trick.

I don't understand what trick. Russia directly attacking NATO? They'd get pulverised, and they have no forces left. Russia committing a suicide by launching a strategic attack on the US over Donbas? That's implausible. They just lost a chunk of Russia proper and took it on the chin.

> I guess everyone who doesn't agree with your assessments is either paralyzed by irrational fears, and/or a useful idiot, or just looking for a cop-out.

I see how it's easy to interpret the earlier reply personally, my bad, sorry. I was referring to the people establishing the narrative (media, politicians, and people with large platforms). It's self evidently working! A direct confrontation with Russia (a country with an economy smaller than Italy's, glaring manpower problems, and largely depleted army) evokes the idea of WW3, but I see very few people talking about the very likely war over Taiwan (with a much, much, much more powerful country) in "WW3" terms. This narrative doesn't make any logical sense, we just got used to it, even though it's not grounded in reality.

Re: New laser could cram GPS alternative into a shoebox

#86

Post by night862 »

minetest2048 wrote: post #82
cyberax wrote: post #78

Another obvious idea: use mega-constellations. GPS signals can't be signed because the signal bandwidth is limited, a digital signature is going to take hours to get transmitted. But by using something like a Starlink satellite, it's possible to transmit digitally signed timing packets that can't be spoofed.

Galileo open signals are signed: https://www.gsc-europa.eu/galileo/services/galileo-open-serv... and it have the same data throughput as GPS L1

It’s a newer development, GPS proper doesn’t support signing. Galileo is a different satellite.

Re: New laser could cram GPS alternative into a shoebox

#87

Post by Animats »

askvictor wrote: post #84
MichaelZuo wrote: post #83

Earlier quoted context omitted.

Pilots can be instructed to ignore GPS related warnings and not trust GPS based systems for the one or two hour duration while they are transiting the jammed airspace. Better yet they can be disabled temporarily since presumably the same proof can be shown to the relevant regulators, airline HQ, etc… They aren’t automatons that must obey every single system installed in the plane regardless of how absurd the outputs…

Yeah, I would guess that a spoofed signal wouldn't be that hard to detect - though you'd presumably need the GPS receiver to be capable of this. A spoofed signal would have to be stronger than the real thing in order to drown it out, no? So as a first guess - if a signal is unreasonably strong, the signal is probably spoofed, so warn the operator.

Read the Ops Group report. It is a very real problem. They explain it clearly. Many highly qualified people are concerned about GPS spoofing.

(Ops Group is a professional group for international pilots, flight planners, or, as they say, people who have a callsign or answer the phone "Ops".)

Re: New laser could cram GPS alternative into a shoebox

#88

Post by aguaviva »

dgroshev wrote: post #85
aguaviva wrote: post #80

Earlier quoted context omitted.

A high-altitude detonation is not a "World War" Obviously (as in very obviously) this wouldn't be the big one in itself, but an entirely possible provocation that could shove things in that direction. China is a significant inhibiting factor, but one factor among many. "Client state" is a caricature, the relationship is more complex than that. Also, no one is "pushing Russia's back against the wall" in Ukraine, there…

> an entirely possible provocation that could shove things in that direction How? What plausible pathway do you see between Russia exploding a nuke over Novaya Zemlya and their suicide by American nuclear response? > A major shift in the ground situation Ukraine's favor (effectively signaling an eventual Russian defeat) could do the trick. I don't understand what trick. Russia directly attacking NATO? They'd get pulv…

Why are you picking the oblique and obviously implausible case of Putin trying to "scare" the West by detonating a device on his own territory (and as far away from his adversaries as possible)? What people are worried about is a low-yield device over the Black Sea or the North Sea, say.

The "pathway" is that any deployment of a device will at the very least trigger a suite of necessary countermeasures on both sides (moving assets around and so forth), greatly increasing the risk of misperceptions and panic reactions.

I don't understand what trick. Russia directly attacking NATO?

The "trick", by which I mean outcome simply, of pushing the regime into an (acutely) fatalistic mindset. The reaction doesn't have to be a direct attack on NATO. It could be some other form of escalation (of the sort they might have ruled out otherwise). It doesn't even have to be an action taken by Russia. It could a matter of China looking at the situation and thinking, in terms of the move they've always been threatening to make, "now or never".

I'd rather not delve into scenarios; I'm just advocating that we observe the cautionary principle here. We agree that the risk is overstated, and that the aggressor's threats are mostly bluster. But it's definitely not negligible risk, in my view; probably on the order of 3-5 percent per year. As high as at any time since the Cuban missile crisis, in any case.

Re: New laser could cram GPS alternative into a shoebox

#89

Post by xandrius »

ck2 wrote: post #15

I wonder if we are within a century of having pulsar detection on a chip. Document enough millisecond pulsars and find your position anywhere in the galaxy. When signal reception and computing power get powerful enough, put it on your wrist.

Problem is always going to be power rather than computation.

I still haven't heard of any major breakthrough in the size of our batteries but when that comes we'll be miniaturizing literally anything.

Re: New laser could cram GPS alternative into a shoebox

#90

Post by Majromax »

red75prime wrote: post #44
Majromax wrote: post #12

Earlier quoted context omitted.

> Could one derive the Earth's rotation? Yes, existing gyroscopes are sensitive enough for that. In 1966, one of the first Soviet attempts to launch the Soyuz failed on the pad because the guidance system remained active after a scrubbed launch attempt. After a couple of hours, the Earth had rotated enough such that the guidance system thought it was off-course, triggering the still-armed launch escape system. > The…

> that the galaxy's gravitational acceleration on the solar system is on the order of 10^-10 m/s A free falling accelerometer (that is an accelerometer that moves along a spacetime geodesic) will detect no acceleration. And the solar system "free-falls". I don't see how we can detect that.

Good point, I retract that comment about detectability. I was too concerned with magnitudes to consider the rest of it.
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