Ships must practice celestial navigation
usni.org
usni.org
* 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-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 :)):
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.
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.
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.
And the best way to achieve that is creating a wedge between the US and its allies.
India and China just barely wrapped up hostilities, and maintain geopolitical contest with each other. India is increasing defence ties with America. Egypt and the UAE host American armed forces.
BRICS is a propaganda tool for leaders who want to blame their failures on a foreign boogeyman. About the best thing for American (and dollar) hegemony would be BRICS continuing to exist. (Versus e.g. China internationalising the renmimbi.)
LOL. USSR had plan how to win war with NATO called «icebreaker» («ледокол»): influence elections or bribe politics in enemy countries to put puppets into powerful seats, then use puppets to start internal conflicts between members of NATO, then support a single side or both sides in the proxy war.
However, on a military level, Russia is being held off by the Ukrainian people (and 37% of the Ukrainian economy) supported by foreign donations equivalent to the current military spending of any one of the United Kingdom (2.33% of the UK's GDP), Germany (2.12% of German GDP), or France (2.06% of French GDP).
If Poland was both threatened and totally isolated from allies, they could triple their military spend to equal the current Ukrainian forces plus all donations, and do so with only half the percentage of their GDP as compared to Ukraine.
Everyone would rather that this war goes away and they can return to spending money on things that are directly valuable, rather than the necessary but un-productive task of defending all the things we value.
But from a purely military perspective, ignoring how they may sow dissent, my only worry about Russia is that the nukes might not have had all their critical elements sold off in separate black market deals since the end of the cold war.
Russia currently is marching forward in Eastern Ukraine, while Ukrainian partners are recommend to use Ukrainian children instead of promised shells.
Poland is ready to 2022 style of war, but not ready to 2023, 2024, or 2025 style of war.
With each passing year, nukes are easier to manufacture. 1GHz switches are not a n advanced tech anymore. WiFi is working on 6GHz. Nuclear isotopes can be separated at home. Gas turbines are outdated. Nuclear reactions inside nuke can be modeled on gaming notebook. No need for testing. More and more nuclear reactors lowers barrier to tech and radioactive elements. Small 2 kWt reactor with size of washing machine can be built to breed highly radioactive elements.
At some point, everybody will be able to produce nukes or dirty bombs using off the shelf items. We are running out of time anyway. Hiroshima and Nagasaki are forgotten.
I'm saying it isn't necessary to do so, if the enemy is the Russian armed forces.
If the enemy is the Russian propaganda machine, that may be harder, but the armed forces are a joke and it's embarrassing that the rest of the world isn't supporting the Ukrainian military to the level required to make the Russian people themselves remove Putin for wasting Russia's own youth.
(Also: Merkel isn't in, nor is she running for, office).
> With each passing year, nukes are easier to manufacture.
They were never hard, by modern industrial standards. The Russian industrial base isn't up to "modern", they have a lot of corruption, and MAD lends itself to visible threats more than real threats, which means there's a decent chance of any given weapon being a Potemkin.
I've heard serious analysts suggest that Ukraine is merely a few months away from their own independent nuclear capability. But also this is a separate question to delivery systems — and the Russian equipment in general looks shoddy and cheap, as if corruption has hollowed it out.
(My guess is that most Russian nukes have lost fusion boost, most of the *nuclear-capable* missiles can't fly, and most of those which can fly can be shot down by very old anti-missile systems; but this all adds up to about a 90% chance they can't start something if they want to, which isn't odds I'd willingly gamble when the stakes are so high).
> 1GHz switches are not a n advanced tech anymore. WiFi is working on 6GHz.
> Gas turbines are outdated.
None of those are even vaguely relevant.
> Nuclear isotopes can be separated at home.
> More and more nuclear reactors lowers barrier to tech and radioactive elements. Small 2 kWt reactor with size of washing machine can be built to breed highly radioactive elements.
Only in the same technical sense that I can make a nuclear fusion reactor at home. (I really should put together that shopping list…)
The requisite isn't simply "doing it", but the scale and the speed of doing so.
> Nuclear reactions inside nuke can be modeled on gaming notebook. No need for testing.
"In theory, theory and practice are the same. In practice, they are not."
This is also important for confirming that, for example, the tritium boost was actually refreshed with hydrogen-3 rather than the much cheaper but chemically identical hydrogen-1, by someone who pocketed the difference and went on to take early retirement in a small island in the Caribbean.
> At some point, everybody will be able to produce nukes or dirty bombs using off the shelf items.
For dirty bombs, that was true years ago. I think we've actually mostly stopped using americium-241 in smoke detectors? We've definitely stopped using radium for glow-in-the-dark paint. I think thorium still gets sold as welding supplies, but no longer for gas mantles.
But a dirty bomb[0] is to a nuclear bomb[1] as a legal and eye-safe laser pointer[2] is to the NIF lasers… if you stacked up about half a million copies of the National Ignition Facility.
There's thermodynamic limits to nuclear isotope enrichment, and while (I assume) all the relevant info is classified, it's reasonable to guess that it would take burning in the order of a million USD worth of energy to make a minimum viable nuclear explosive.
(Ironic risk factor from PV: much cheaper electricity)
[0] continuous radiohazard that can be hundreds of milliwatts/gram, where a gram of material costs ~ $1500
[1] pulse measured in terajoules
[2] ~1mW
[3] NIF laser pulses are about ~2 megajoules light energy per pulse, so half a million copies would get you 1 terajoule, compared to Fat Man's 88 TJ; ~88 laser pointers gets you the same CW equivalent power of ~1000 USD of americium-241.
To be a health hazard, you'd have to eat or inhale a sample. Which has been made to happen, but it looks like poisoning, not like a bombing: https://en.wikipedia.org/wiki/Alexander_Litvinenko
This is why, despite all the fear of dirty bombs during the War On Terror, we didn't see any.
A semi-joke-y observation:
> Pretty straightforward really. You combine Brazil's history of monetary stability, with Russia's respect for property rights, India's domestic tranquility, China's financial transparency, and South Africa's investment opportunities - and hey presto, you've got a new global money.
* https://twitter.com/davidfrum/status/1665053372402081792
If the 'BRICS currency' is made up of only a small group, then it's not going to be useful, especially the restrictive countries that are in the name.
But if you expand it, sure it could become more useful, but then you've got competing interests and desires and a coördination problem on policy and such.
Further: I've yet to see an explanation of how this thing will actually work. Does each country given up their own currency, Euro-style? Is there a 'theoretical currency' that everyone pegs their own to? What are the consequences for de-pegging (if any)? Are bonds issued in BRICS or the country's own currency?
Although I have to assume that with Trump as president for a second time a lot of people in europe are going to have to worry that the US can't be relied on in the way it could in the past so I think you might get your wish.
Where that leaves NATO afterwards, I don't know.
It’s been a policy of the US government to discourage strong independent European militaries since about 1945. Same policy towards Japan, too.
I’m pretty sure that war requires congressional approval BEFORE an invasion full stop. Congress in recent history has been fairly cavalier about letting the executive launch military action and looking the other way, but it’s not actually supposed to work this way.
> 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
This is a gross mischaracterization of the situation that significantly underplays what actually happened I think. Without what Biden did right before the war saying “it’s going to happen” and mustering broad domestic and international support as well as using sanctions to freeze Russian assets and use them to pay Ukraine for reparations, Ukraine wouldn’t exist today.
We’re talking about $70B of military HW and $23B in terms of economic and humanitarian aid and another ~87B for the Ukrainian government to keep the lights on. That’s from the US alone. The international community has also contributed another $100B.
> 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.
It’s a slower burn. Putin isn’t going to try to take everything at once. It’s the Hitler annexation strategy over a longer time period. A little Georgia here, a little Crimea there, now it’s the entirety of Ukraine. Partly because his country is weaker but also because war is more expensive to prosecute than 100 years ago due to technology and the resistance is much better prepared for such an attempt.
Where do you think Eastern and Western European civilians will flee if any of those countries is drawn into conflict with Russia? Conflict forces desperate immigration which then creates anti-immigration counter responses in domestic populations here in the US.
China is important but what are we going to do there? Do you think we’re going to successfully defend an invasion of Taiwan when it happens? Cause that’s going to be their first military action. And if people are complaining about supporting Ukraine, how do you think they’ll fair regarding Chinese nationalists?
Finally, I’m pretty sure the troops and equipment we need there are also fairly different. If China is delivering huge numbers of land troops to Taiwan in the first place I’d say the battle is very lost. It’s going to be a sea/land siege so if the US gets directly involved it’ll be a meeting of the navies.
Thousands of european soldiers have died because of US war on terror the last decades, not the other way around.
When countries start threatening those who aren't their active enemies, it's a first step into normalization of the rhetoric and building up support for inhuman actions. Iraq wasn't even in anyone's mind until suddenly America needed to invade and "liberate" it just for some president's personal ego, and the overwhelming majority became convinced that Iraq was involved in 9/11 (it wasn't) and steamrolling the entire country was doing the world a public service (it wasn't)[1]. Nobody was even thinking about Greenland or Denmark in the US until someone with a big ego started talking about liberating it. Now the same political faction that had 89% support for the Iraq War is starting up the same thing.
[1] https://www.pewresearch.org/politics/2023/03/14/a-look-back-...
All that being said, Americans grew up, long before Donald trump entered the political discourse, learning that they live in the greatest country on earth and that everyone wants to move there and become American. This is a core component of Donald trump’s political message of make America great again. So why wouldn’t the average American be accepting the idea that other places want to join in on the fun? Democrat or Republican most seem to buy in to American exceptionalism.
* Sadam Houssein (and Kadhafi, and Khomeini) regularly moaned about the US
* everybody was indeed aware of them
* and everyone ignored them
* for most people outside the US, the second gulf war was perceived a transparent lie
One look at the ridiculous "coalition of the willing" that GWB managed to drum up makes that clear.
https://en.wikipedia.org/wiki/Coalition_of_the_willing_(Iraq...
As a European (now living in the US) I think this perspective might be an oversimplification. Access to EU soil has been incredibly important for US military strategy over the last 50 years. Having bases in Germany, Spain and Italy is instrumental in US campaigns in Middle East or Asia. Not to mention the amount of European lives lost in conflicts initiates or led by US interests.
https://en.wikipedia.org/wiki/California_Border_Protection_S...
* https://en.wikipedia.org/wiki/File:NGA-Atlantic_Loran.png
The chains run by Japan are not dependent on the chains run by South Korea, would not be dependent on chains run by AU or NZ:
* https://en.wikipedia.org/wiki/File:NGA-Pacific_Loran.png
* https://en.wikipedia.org/wiki/Loran-C#Limitations
India, China, and Pakistan could all run their own infrastructure:
* https://commons.wikimedia.org/wiki/File:Loranstationscrkl.jp...
The only agreement being the technical standards (frequencies) and timing offset for near-by chains.
(And I'm Canadian.)
A western defense system that excludes the USA is naive at best.
If these countries were our allies the answer would be “I have no idea why you would even be thinking that question”, not “we won’t rule anything out”.
I hate to sound snarky, and I mean this genuinely, but forcing people to defend someone is not a way to generate allies. A decade of “what he actually said was” is enough to turn even the most strident progressives towards the middle at least.
The problem is who will control the entrance and exit to that route and GIKU is one of them. And here we are on the key problem: Denmark for years totally neglected building any security/military infrastructure on Greenland, which suddenly might become a crucial element of the World economy and trade.
Do you really want sadistic regimes like Russia or China to take control over key parts of the potential trade routes (80% of global trade goes through the sees and oceans)?
Whatever you think about Trump, he will be gone in 4 years, someone else can be elected if Trump/Vance fails to deliver. Do you think we can get rid of Putin and his dreams on conquests Europe that easily? Or Xi, who is speeding with extending military potential of China, including nuclear weapons, aircraft carriers? Try to guess why Xi is doing this.
But let's just wait and see, actions speak louder than words, although given past actions that is not instilling great confidence in me.
Yes, someone could invade. But they didn't.
And if they did, they probably wouldn't have been able to stay there for long enough to actually get anything out of it long term, without it turning into a war against NATO.
It is my understanding that it has been agreed a few years ago that additional monitoring should be put in place. I don't think anything else than general tech incompetence of the Danish defense forces has prevented that from happening yet.
But on the hand, as far as I understand the matter, there is still too much ice for it to become a major trade route.
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.
https://idstch.com/geopolitics/denial-gps-services-kargil-wa...
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.
You can try it yourself here:
I wonder if this mindset is also applied, for example, to the rest of the military. Does the Army regularly practice land navigation? I know they get at least one landnav class, but it is a perishable skill. If you don't practice, you'll soon forget about it.
I guess this could also be useful to civilians. Being able to do stuff without relying too much on electronics.
The point is not to rely on GPS/GNSS:
In any case, as others have said, in the ocean a cellphone is useless for navigation. At least use a standalone satellite navigator. And learn to use paper maps and a sextant, it's actually a lot of fun.
See, for instance:
https://www.rocketlabusa.com/space-systems/satellite-compone...
TL;DR star tracking is a thoroughly solved problem, the hard problem is finding "where is down" without looking at the horizon (which may not be visible). The solution to that is coupling into the ship's inertial navigation system, which still may drift up to an arcminute per hour, but if you feed the star tracker data back into the INS for corrections, it gets better.
The stars only give you the angle at which you're looking at the sky. If you know the angle to the center of the earth (or can relate the sky measurement to that) and the exact time, you know where you are, within the inaccuracy of your measurements. Being 1/60th of a degree (1 angular minute) off places you 1 nautical mile off.
A bubble sextant solves this by including a literal 2D bubble level. "When properly used, the bubble sextant gives good results, by which we mean an accuracy to within 5 miles." (https://www.usni.org/magazines/proceedings/1939/june/averagi...).
The obvious solution that immediately springs to mind is a tilt sensor/accelerometer. However, once you get to a useful accuracy, those start getting expensive - several hundred dollars for a 0.01 degree system, which would give you an error of about 1 km.
You'd then need a sufficiently rigid mount for everything, proper calibration (remember, some angle on your mount being 0.05 degrees off completely destroys all usefulness of your system!), and then a camera and a plate solver (software that turns a photo into sky coordinates) should give you a useful fix. I think you could build a system that gets you within a few nautical miles for about $1000 (parts, not labor).
Problem is those fly high enough that the sky is pretty dark and you can actually see stars.
That's not an assumption we can make for the avg plane
A round-the-world yacht race where modern technology is not permitted. (Where 'Modern' = pretty much anything that wasn't in common use in 1970's/1980's).
A fair few of the boats that have taken part had previously run the Whitbread Race in 80's.
GPS isn't permitted outside of emergency situations, and neither are mobile phones/computers (which are sealed in a bag by race organizers for the duration of each leg).
Celestial navigation is required iirc.
Other banned items include: - Carbon Fiber - Digital Music (Only cassette tapes permitted!)
It’s also no big deal to go 12 hours with no position. If you know your speed and heading you can accurately estimate your position much longer than that.
Overall, they also made it sound almost impossibly difficult for a large team of professionals, when solo and otherwise short handed recreational sailors have been reliably sailing around the world with celestial navigation for more than a century- through all possible conditions.
My understanding is that the sextants are coming from breaker yards in India where the sextants were left on ships and salvaged.
As a sibling comment notes, it is possible. There are tables for lunar distance:
* https://thenauticalalmanac.com/Lunar_Distance_Tables.html
* https://en.wikipedia.org/wiki/Lunar_distance_(navigation)
* https://www.starpath.com/resources2/brunner-lunars.pdf
The planets Venus, Mars, Jupiter, and Saturn can be used, as well as several dozen planets (lookup tables in an almanac)
* https://en.wikipedia.org/wiki/Nautical_almanac
* https://thenauticalalmanac.com
Two US military videos explaining the theory (ground points/GP, circle of position, etc):
* USAF: https://www.youtube.com/watch?v=UV1V9-nnaAs
* Army: https://www.youtube.com/watch?v=G4DRBi66cOA
The USAF has a video because that's how planes used to do navigation outside of radio range—sextants on the ceiling of the cockpit:
Pretty impressive! USS Essex would cover 10nm in about half an hour, so not much tolerance for going off-course.
Compared to what the Navy usually steers by, how advanced and expensive are bubble sextants?
That's the only "expensive" equipment needed for celestial navigation or at least that was the case when I learned it over 40 years ago.
I'm not sure exactly what methods were used in this navigation exercise, but if they write down numbers with finite precision at any point in the process, then the method has at least some digital component to it. Note that digital means the use of digits, not necessarily any involvement of computers or electronics.
For example, if they take a reading on a sextant, write down a number, and manually transfer it to a coordinate on paper, then that is a semi-digital process. If they take a number and then look up some kind of trigonometric table, that is definitely digital and not analog. But if the navigation process entirely consists of analog mechanical linkages and at no point any number is read out, then I would deem it 100% analog.
> using the radian rule, steering 1 degree off base course for 12 hours at a speed of 16 knots results in nearly 3.5 nm left or right of track (565 yards per hour)
This brings up a laughable feature of the US customary measurement "system", a hodge-podge of units with no coherent logic to it: 1 nautical mile ≈ 2025.371... yards, an awkward number that isn't even whole. This is because 1 nautical mile = 1852 metres exact and 1 yard = 0.9144 metre exact. Converting between these units would be a pain. (Whereas at least 1 mile = 1760 yards exact.)
Analogously, let's say you're piloting an airplane at an altitude of 15000 feet and have a horizontal distance of 7 nautical miles to your landing site. What would be the descent angle if you flew down in a straight line? The answer is not immediately obvious because you can't do trigonometry on different units. Whereas if I said you're 4572 m high and 12964 m horizontal distance away, then the angle is arctan(4572/12964) ≈ 19.4°. And even if distances are reported in kilometres, even a child knows that 1 km = 1000 m.
Btw, digital logic can be made out of LEGO, fluidics, electromagnetic (not electronic!) relays, steel plates (old railway signaling logic).
BTW you can do digital logic on… actual digits/fingers. But when someone says “digital signal processor” that’s not usually what they mean. Sadly.
Do you mind sharing what that station is with the class, or where it is on the dial?
I mean, when an ad says "Listen to 123.4 FM!", they are literally conveying that information to you digitally; they are telling you the number to tune to.
A fully analog radio has markings to give you a rough guide of where the frequencies are, e.g. 99.0 MHz, 99.1 MHz, 99.2 MHz, etc. When you take the number in your mind and map it onto the markings, you are performing a digital-to-analog conversion (DAC). And because the dial is analog, you can make it fall between any marking you want; there are no steps that you're forced to take.
Meanwhile, a digital tuner would let you tune to 99.1 MHz and 99.3 MHz with nothing in between.
If you want odd American units you should check out surveying. Units vary by geographical region.
Uh yeah they are. They are _customarily used_ in the US, so they count. They're literally used on all ships and planes. Any unit that is broadly used in the USA is USC. Further, they are indeed listed under the USC page: https://en.wikipedia.org/wiki/United_States_customary_units .
I use an app to double check my hand calculations.
Of course if you have a GPS signal you can keep time to within nanoseconds, but I suppose we're assuming GPS is jammed.
Cellphone cameras typically have pixel pitch on the order of 250 microradians, but star trackers routinely deliver attitude information accurate to less than a tenth of a pixel, so 25 microradians, which is 5 arc seconds, not "a few degrees". Calibrating a star tracker for a mass-market camera with its nonlinear distortions is a pain in the ass but can be done. 25 microradians is 160 meters.
SatState from F-Droid shows that my cellphone's accelerometer (tilt sensor) seems to vary by ±0.01m/s² in each of its ≈200ms samples, which is about a milliradian of error, 40× worse than the camera error, about two weeks of clock drift. This isn't "a few degrees" either. Accelerometers can integrate over arbitrarily long periods of time to reduce noise; to reduce noise by 40×, assuming a Gaussian distribution, you need about 1600 samples (320 seconds, 5 minutes and 20 seconds) to average out to the same level as the camera error.
(It's easiest if the phone is sitting still during the averaging time, but both the gyros and the star tracker attitude information permit you to usefully average the accelerometer signal over time even when the phone is changing attitude.)
You probably do need to calibrate the angle between the accelerometer and the camera, but it probably won't change significantly over time for a given phone.
The clock seems like it could be the weak point here, but even the clock is only drifting a few hundred meters a day, and that only produces an east-west error.
> Any navigation equipment that used electricity was prohibited, including all GPS sources, the Essex’s electronic Voyage Management System (VMS), and the computer-based celestial navigation software STELLA.
That defines the scope of the exercise.