6 ms·

Training for this was discontinued, but brought back in 2016: * https://www.npr.org/2016/02/22/467210492/u-s-navy-brings-back-navigation-by-the-stars-for-offic

Training for this was discontinued, but brought back in 2016: * https://www.npr.org/2016/02/22/467210492/u-s-navy-brings-back-navigation-by-the-stars-for-officers https://www.npr.org/2016/02/22/467210492/u-s-navy-brings-bac... Now if only the US (and others) would get their act together and build out a backup system to GNSS. China, for example, has built out an eLoran system: * https://rntfnd.org/2024/10/03/china-completes-national-eloran-network-the-paper/ https://rntfnd.org/2024/10/03/china-completes-national-elora... An old USAF video explaining how the theory works (it assumes a geocentric worldview: the Earth is the centre of the universe (but it's not flat :)): * https://www.youtube.com/watch?v=UV1V9-nnaAs https://www.youtube.com/watch?v=UV1V9-nnaAs

dzhiurgis 2y ago
> Now if only the US (and others) would get their act together and build out a backup system to GNSS They are moving towards quantum navigation (esp subs)
- throw0101a 2y ago
  > They are moving towards quantum navigation (esp subs) How does that help the merchant marine that is part of the logistical supply chain? Are container ships going to get this quantum nav boxes too? The US pays airlines a retainer to be a reserve fleet [1]: will they get these boxes as well in case of emergency? What happens to all the civilian infrastructure that need navigation and timing signals? Considering only the "military" ramifications of GNSS disruption is myopic. [1] https://en.wikipedia.org/wiki/Civil_Reserve_Air_Fleet https://en.wikipedia.org/wiki/Civil_Reserve_Air_Fleet
pbhjpbhj 2y ago
The USA who just threatened to invade a few NATO allies? People working with USA for the next few years seems pretty foolhardy. Surely everyone else in NATO needs to be getting together and building it defense system that exclude USA.
- scottLobster 2y ago
  I'm pretty sure the threatened invasions are just distractions to change the conversation from the H1B debacle. If for no other reason than Canada is a country a lot of Americans actually care about (many have relatives there), and without a formal declaration of war congress could step in at any time and declare the whole thing illegal, enabling the military to refuse orders relevant to the invasion. But as an American who has been a little sick of Europe mooching off of our military overwatch (see various European nations running out of bombs during the Libya campaign), I'm all for an independent European military command with independent capacity. The Cold War is over, the Russian tank hordes that once threatened to roll across Western Europe haven't managed to roll halfway across Ukraine with even reluctant, intermittent, indirect western support. We don't need to be under some monolithic military command anymore, Europe does not (or at least should not) need US strategic overwatch to fend off Russia. As for the "European militarization has historically led to world wars" argument, the UK, France, and Russia all have nukes. Germany could probably build a few in a long weekend if sufficiently motivated. We aren't going to see a WWI or WWII rematch unless the AI "revolution" actually turns out to be more than smoke and mirrors for dumb money and enables perfect missile defense or something. So yeah, please get an ex-US NATO off the ground so we can focus on China.
  - jltsiren 2y ago
    > So yeah, please get an ex-US NATO off the ground so we can focus on China. If the US does not care about its European allies, it no longer has the economic power to "focus on China". From an European perspective, China is far away and not particularly threatening. If there are no specific reasons to support the US, it's better to not take sides and trade with both sides. BRICS is already a serious challenge to the Western hegemony. If the US thinks that "the West" has no longer a reason to exist, it will be seriously outnumbered by those who don't share its ambitions.
    - nradov 2y ago
      BRICS is a total joke. Some of the member countries have taken limited unilateral actions to challenge Western hegemony but BRICS as a group has never taken any meaningful coordinated action and never will. India won't go along with anything that benefits China. South Africa is a failed state. Brazil has no global ambitions. And the Russian Empire is bleeding to death in Ukraine; even if they eventually "win" their ability to challenge us has disintegrated.
dylan604 2y ago
> Now if only the US (and others) would get their act together and build out a backup system to GNSS. China, for example, has built out an eLoran system: What prevents other countries from using these other systems?
- throw0101a 2y ago
  > What prevents other countries from using these other systems? Nothing. Nothing also prevents other countries from using China's BeiDou GNSS or their eLoran network.
- nayuki 2y ago
  Encryption. For example, GPS's P(Y) code is encrypted and only for military use. https://en.wikipedia.org/wiki/Global_Positioning_System https://en.wikipedia.org/wiki/Global_Positioning_System
  - dylan604 2y ago
    But that’s what the three letter agencies are supposed to do. Surely there’s a good guy back door to that encryption /s
- knifie_spoonie 2y ago
  The US government can apparently turn off their GPS signals over certain parts of the world: https://idstch.com/geopolitics/denial-gps-services-kargil-war-driven-isro-develop-indian-regional-navigation-satellite-system-irnss-superior-gps/ https://idstch.com/geopolitics/denial-gps-services-kargil-wa...
madphilosopher 2y ago
The main principle of celestial navigation is pretty easy to visualize. Pick a celestial body that's in your sky right now, like the Sun. At any given time, the Sun is directly over a single point on the globe (the GP, or Geographic Position). So if you measure the Sun as being directly over your head, you know where you are exactly on the globe, after consulting your clock and almanac. But, if you measure the Sun at a non-overhead angle, then you and everyone else with that same measurement must be on a circle whose centre is the Sun's GP. (Visualize the circle as the edge of a flashlight beam being pointed directly downward at the GP.) The rest of celestial navigation is refinements to figure out where you are on that circle.
- Onavo 2y ago
  You can also do it at night using star charts (or as you call it, an "almanac"). That's how most of the digital celestial navigation solutions work, they use the positions of bright stars to determine a fix based on observatory data. You can try it yourself here: https://nova.astrometry.net/ https://nova.astrometry.net/
- nonrandomstring 2y ago
  Might I differ on "easy", from second hand experience of watching my father go through his advanced yachtsmanship RYA Astro Navigation exams and cursing at trig functions? In practice its a lot of paper and compasses.
Almondsetat 2y ago
the Earth is the center of the universe, though, just like any other point in space

dzhiurgis 2y ago

> Now if only the US (and others) would get their act together and build out a backup system to GNSS They are moving towards quantum navigation (esp subs)

throw0101a 2y ago
> They are moving towards quantum navigation (esp subs) How does that help the merchant marine that is part of the logistical supply chain? Are container ships going to get this quantum nav boxes too? The US pays airlines a retainer to be a reserve fleet [1]: will they get these boxes as well in case of emergency? What happens to all the civilian infrastructure that need navigation and timing signals? Considering only the "military" ramifications of GNSS disruption is myopic. [1] https://en.wikipedia.org/wiki/Civil_Reserve_Air_Fleet https://en.wikipedia.org/wiki/Civil_Reserve_Air_Fleet

pbhjpbhj 2y ago

The USA who just threatened to invade a few NATO allies? People working with USA for the next few years seems pretty foolhardy. Surely everyone else in NATO needs to be getting together and building it defense system that exclude USA.

scottLobster 2y ago
I'm pretty sure the threatened invasions are just distractions to change the conversation from the H1B debacle. If for no other reason than Canada is a country a lot of Americans actually care about (many have relatives there), and without a formal declaration of war congress could step in at any time and declare the whole thing illegal, enabling the military to refuse orders relevant to the invasion. But as an American who has been a little sick of Europe mooching off of our military overwatch (see various European nations running out of bombs during the Libya campaign), I'm all for an independent European military command with independent capacity. The Cold War is over, the Russian tank hordes that once threatened to roll across Western Europe haven't managed to roll halfway across Ukraine with even reluctant, intermittent, indirect western support. We don't need to be under some monolithic military command anymore, Europe does not (or at least should not) need US strategic overwatch to fend off Russia. As for the "European militarization has historically led to world wars" argument, the UK, France, and Russia all have nukes. Germany could probably build a few in a long weekend if sufficiently motivated. We aren't going to see a WWI or WWII rematch unless the AI "revolution" actually turns out to be more than smoke and mirrors for dumb money and enables perfect missile defense or something. So yeah, please get an ex-US NATO off the ground so we can focus on China.
- jltsiren 2y ago
  > So yeah, please get an ex-US NATO off the ground so we can focus on China. If the US does not care about its European allies, it no longer has the economic power to "focus on China". From an European perspective, China is far away and not particularly threatening. If there are no specific reasons to support the US, it's better to not take sides and trade with both sides. BRICS is already a serious challenge to the Western hegemony. If the US thinks that "the West" has no longer a reason to exist, it will be seriously outnumbered by those who don't share its ambitions.
  - nradov 2y ago
    BRICS is a total joke. Some of the member countries have taken limited unilateral actions to challenge Western hegemony but BRICS as a group has never taken any meaningful coordinated action and never will. India won't go along with anything that benefits China. South Africa is a failed state. Brazil has no global ambitions. And the Russian Empire is bleeding to death in Ukraine; even if they eventually "win" their ability to challenge us has disintegrated.

dylan604 2y ago

> Now if only the US (and others) would get their act together and build out a backup system to GNSS. China, for example, has built out an eLoran system: What prevents other countries from using these other systems?

throw0101a 2y ago
> What prevents other countries from using these other systems? Nothing. Nothing also prevents other countries from using China's BeiDou GNSS or their eLoran network.
nayuki 2y ago
Encryption. For example, GPS's P(Y) code is encrypted and only for military use. https://en.wikipedia.org/wiki/Global_Positioning_System https://en.wikipedia.org/wiki/Global_Positioning_System
- dylan604 2y ago
  But that’s what the three letter agencies are supposed to do. Surely there’s a good guy back door to that encryption /s
knifie_spoonie 2y ago
The US government can apparently turn off their GPS signals over certain parts of the world: https://idstch.com/geopolitics/denial-gps-services-kargil-war-driven-isro-develop-indian-regional-navigation-satellite-system-irnss-superior-gps/ https://idstch.com/geopolitics/denial-gps-services-kargil-wa...

madphilosopher 2y ago

The main principle of celestial navigation is pretty easy to visualize. Pick a celestial body that's in your sky right now, like the Sun. At any given time, the Sun is directly over a single point on the globe (the GP, or Geographic Position). So if you measure the Sun as being directly over your head, you know where you are exactly on the globe, after consulting your clock and almanac. But, if you measure the Sun at a non-overhead angle, then you and everyone else with that same measurement must be on a circle whose centre is the Sun's GP. (Visualize the circle as the edge of a flashlight beam being pointed directly downward at the GP.) The rest of celestial navigation is refinements to figure out where you are on that circle.

Onavo 2y ago
You can also do it at night using star charts (or as you call it, an "almanac"). That's how most of the digital celestial navigation solutions work, they use the positions of bright stars to determine a fix based on observatory data. You can try it yourself here: https://nova.astrometry.net/ https://nova.astrometry.net/
nonrandomstring 2y ago
Might I differ on "easy", from second hand experience of watching my father go through his advanced yachtsmanship RYA Astro Navigation exams and cursing at trig functions? In practice its a lot of paper and compasses.

Almondsetat 2y ago

the Earth is the center of the universe, though, just like any other point in space