But like an IMU, doesn’t this need occasional calibration with a known location source?
Yes, but if it's accurate enough then the frequency of recalibration can be kept low enough that inertial navigation can be practical.
New laser could cram GPS alternative into a shoebox
61–70 of 103 posts
Re: New laser could cram GPS alternative into a shoebox
#62We’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 s…
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.
Re: New laser could cram GPS alternative into a shoebox
#63The main application would obviously be missiles and autonomous military drones. If you can use GPS - you should. It's crazy cheap and it doesn't accumulate errors over time. But in a war GPS can be jammed. This can't.
Commercial airliners and ships badly need this functionality.
Re: New laser could cram GPS alternative into a shoebox
#64Earlier quoted context omitted.
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.
I would assume that the refrigerator sized ones are definitely already in submarines.
Maybe, but this isn't the only way to build a high performance accelerometer.
Re: New laser could cram GPS alternative into a shoebox
#65Earlier quoted context omitted.
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…
After integrating the output twice from current COTS accelerometers, position is useless in at most a few minutes.
Re: New laser could cram GPS alternative into a shoebox
#66We’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 s…
> Because modern aircraft have incorporated GPS into a large number of aircraft systems
Aviation is slow. It wasn’t until recently that GPS-based landing approach became common, and even then you’re double checking with ground radar. No commercial airliner would use IMU—if ground-based radar is not operating or coöperating, you get out of that airspace.
Re: New laser could cram GPS alternative into a shoebox
#67Earlier quoted context omitted.
In Russia's case, there does appear to be "no budget". The weapons were intended as a last resort, and so they are a great target for diverting maintenance funds. It's not quite so bad as "we are certain that they will not successfully launch any nukes" and so they're still being treated with caution. But the US keeps upping what it allows Ukraine to do as it loses its fear of World War III. As it applies to the US..…
There is no fear of WWIII, that's part media invention, part political excuse, part useful idiots. A "World War" requires an opponent worthy of a world-wide conflict, and Russia is anything but, being stuck in Ukraine for three years and losing most of its army in the process. Conventionally, Russia is no match for NATO, with enough political will it'd be a Desert Storm-like curb stomp. The only way it's not is the U…
> will immediately alienate China and India
To drive this home, India and China have a moderately high probability of engaging in armed conflict with a nuclear power in the next decades. (India with Pakistan and China, China with America.)
They do not want tactical nukes to be normalised in prelude to those conflicts.
Re: New laser could cram GPS alternative into a shoebox
#68Earlier quoted context omitted.
In Russia's case, there does appear to be "no budget". The weapons were intended as a last resort, and so they are a great target for diverting maintenance funds. It's not quite so bad as "we are certain that they will not successfully launch any nukes" and so they're still being treated with caution. But the US keeps upping what it allows Ukraine to do as it loses its fear of World War III. As it applies to the US..…
There is no fear of WWIII, that's part media invention, part political excuse, part useful idiots. A "World War" requires an opponent worthy of a world-wide conflict, and Russia is anything but, being stuck in Ukraine for three years and losing most of its army in the process. Conventionally, Russia is no match for NATO, with enough political will it'd be a Desert Storm-like curb stomp. The only way it's not is the U…
There is no fear of WWIII, that's part media invention, part political excuse, part useful idiots.
Not true at all. The risk may be overstated by some, but it's a perfectly possible outcome that must be considered.[0]
A "World War" requires an opponent worthy of a world-wide conflict, and Russia is anything but
Also simply not true. It just requires one side to start using nukes, which can also happen entirely by accident (and has come close to happening multiple times, even without a multi-year and incredibly nasty hot proxy conflict on the ground between two of the planet's largest mutual adversaries).
As for nuclear weapons, they are practically useless.
True of course, but it doesn't matter. What matters is that certain people might start to think that they're useful and/or their only choice. Which gets into the fact that we can't assume these people are acting rationally.
Also, notice how Putin and his officials talk about nuclear use a lot, but there is still zero evidence of any action
Right, but that can change at any time. It doesn't even have to be a tactical battlefield strike (which of course would be useless, and their people know it). For example, once their backs are pushed against the wall with sufficient firmness, Putin or his successors might start to think that a demonstrative high-altitude detonation over an ocean somewhere might be a pretty neat idea. Especially if they've reached a point where they have nothing more to lose, and have a reasonable fear of being outright killed sooner or later if the current situation on the ground starts to move strongly and rapidly against them.
Re: New laser could cram GPS alternative into a shoebox
#69Earlier quoted context omitted.
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 s…
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, because there is no terrain on earth at 30k ft. If that had happened at a lower altitude, they would have likely had to do a terrain escape maneuver, which would definitely be felt by passengers, though it would likely not introduce a lot of additional safety risk.
The real risk comes when pilots begin to doubt that their safety systems are working correctly and thus ignore true warnings. Or when a bungled GPS leads pilots to fly into military airspace and get shot down.
Re: New laser could cram GPS alternative into a shoebox
#70Earlier quoted context omitted.
There is no fear of WWIII, that's part media invention, part political excuse, part useful idiots. A "World War" requires an opponent worthy of a world-wide conflict, and Russia is anything but, being stuck in Ukraine for three years and losing most of its army in the process. Conventionally, Russia is no match for NATO, with enough political will it'd be a Desert Storm-like curb stomp. The only way it's not is the U…
There is no fear of WWIII, that's part media invention, part political excuse, part useful idiots. Not true at all. The risk may be overstated by some, but it's a perfectly possible outcome that must be considered.[0] A "World War" requires an opponent worthy of a world-wide conflict, and Russia is anything but Also simply not true. It just requires one side to start using nukes, which can also happen entirely by acc…
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 only allowed melee weapons in border skirmishes with India. There is no way a demonstrative breaking of the taboo would not get Putin's leash yanked, so even that remote possibility (that has nothing to do with WW3) is extremely improbable and would only hasten Russia's defeat. Unless, of course, our politicians use it as an excuse to abandon Ukraine.
Also, no one is "pushing Russia's back against the wall" in Ukraine, there are no M1A2s speeding to Moscow. Russia understands it perfectly well, too, denuding their borders with NATO to throw more soldiers into the meat grinder.
> the fact that we can't assume these people are acting rationally
I think this meme is largely a cop-out. A person just doesn't get to be a leader of a country by acting irrationally. They might interpret things differently or have different priorities, they might even put on an act of irrational buffoonery, but it's different from being "irrational". However, to see the rationality of their actions requires putting yourself in theirs shoes, which is uncomfortable and/or requires a deeper understanding, so it's easier to just write their behaviour as "irrational".
Putin is perfectly rational. The empty threats are working (as evidenced by this thread), there is no risk of a strategic exchange (because the actual signalling on the ground is one of business as usual), and Western politicians are successfully convincing their voters that they drag their feet because WW3, not because actually stopping the war (eg deploying a NATO peace keeping force) would incur a substantially higher domestic cost.
We don't really talk about potential North Korean aggression in WW3 terms, do we? We shouldn't do that in Russian case either.