London Underground hosts tests for 'quantum compass' that could replace GPS

Post by darby_nine » Tue, Jun 18, 2024, 10:40 AM UTC

ptsneves wrote: post #103

ta20240528 wrote: post #98

Earlier quoted context omitted.

> has lots of worrying consequences for normal people that are in normal cities. Which is precisely why even the mere ownership of nuclear weapons was ruled by the ICJ to be illegal: a violation of inter alia the Hague [1907], UN Charter and Geneva Conventions. Specifically the Geneva Convention Protocol I (1977) states that ‘the civilian population shall not be the object of attack’. The 1977 Geneva Protocol was rat…

The US does not belong to the ICJ, so that judgement would only be valid if the US Supreme court would say so. I dislike a lot nuclear weapons but they are an escalation deterrent like the humanity never had[1]. I hope they continue to be a deterrent but never ever launched in war. [1] If Ukraine kept the nuclear weapons post USSR collapse we probably would not have the war on Ukraine, lots of dangerous threats but n…

Post by thfuran » Tue, Jun 18, 2024, 11:30 AM UTC

perryizgr8 wrote: post #112

dazzlefruit wrote: post #109

Earlier quoted context omitted.

President: ok, hit this military base with 100 soldiers to let them know we’re serious Million-inhabitants city nearby: burns to the ground due to garbage guidance President: …dig out the plan for world war 3, I guess.

ICBM is likely to deliver a nuke. Which will probably take out a 20 km radius circular area. It is not going to be used to target a base with 100 soldiers.

Post by mannykannot » Tue, Jun 18, 2024, 12:08 PM UTC

mschuster91 wrote: post #99

Animats wrote: post #97

Earlier quoted context omitted.

US ICBMs been inertially guided for decades. They predate GPS. Once launched, they have no radio inputs. Some weapons do use GPS. The Joint Direct Attack Munition, the US's most common "smart bomb", is GPS-dependent. There's an inertial backup, but it's not that good. With GPS, it can hit a bunker or an artillery emplacement or a parked vehicle. Without GPS, small targets are out. DARPA has been working on small, low…

> US ICBMs been inertially guided for decades. They predate GPS. Once launched, they have no radio inputs. That's how the original Third Reich V-rockets worked as well, and they were shockingly inaccurate. It didn't matter for the Nazis, as their intention was to spread terror among the British population instead of actually hitting specific military targets, but in a modern war waged under the rules of war, "collate…

Post by [deleted] » Tue, Jun 18, 2024, 12:59 PM UTC

horstbort wrote: post #61

hi-v-rocknroll wrote: post #14

Earlier quoted context omitted.

Because it can't. There are always cumulative errors in INS. There is no way around this without external references, but then it's no longer inertial navigation and it's inertial-assisted navigation. An underground navigation system based on triangulation of UWB cells would be a better solution than some nonstarter project the size of a refrigerator that requires liquid nitrogen.

There is no liquid nitrogen involved here. The instrument from the article is actually rather big, current generations of quantum IMUs are roughly half this size with lots of room for miniaturization. One big advantage of these atom interferometers is that they actually don't need to be recalibrated because the reference is the wavelength of the lasers which can be controlled with extreme precision. A big disadvantag…

Post by justusthane » Tue, Jun 18, 2024, 1:26 PM UTC

anovikov wrote: post #118

That smells like bs to me.