Slashdot Mirror
Naval Academy Reinstates Teaching of Celestial Navigation
HughPickens.com writes: At the US Naval Academy in Annapolis, midshipmen studied celestial navigation for more than a century -- until 1998, after a decision that came after months of discussion that began with a 1996 curriculum review. Midshipmen were relieved. Celestial calculations were painfully difficult, requiring a nautical almanac and volumes of tables. Now Tim Prudente reports at the Capital Gazette that the Navy has reinstated the teaching of celestial navigation in the manual issued two months ago. The first midshipmen to receive training were juniors during this past summer school. Future classes will learn theories of celestial navigation during an advanced navigation course. And the Class of 2017 will be the first to graduate with the reinstated instruction.
But is there really any point in knowing how to navigate by the stars in a world of GPS? "In the event that we had to go into a national emergency, we would probably have to shut the GPS down because it can be used by potential enemies," says retired Navy Capt. Terry Carraway. "We went away from celestial navigation because computers are great," says Lt. Cmdr. Ryan Rogers, the deputy chairman of the academy's department of seamanship and navigation. "The problem is, there's no backup."
But is there really any point in knowing how to navigate by the stars in a world of GPS? "In the event that we had to go into a national emergency, we would probably have to shut the GPS down because it can be used by potential enemies," says retired Navy Capt. Terry Carraway. "We went away from celestial navigation because computers are great," says Lt. Cmdr. Ryan Rogers, the deputy chairman of the academy's department of seamanship and navigation. "The problem is, there's no backup."
Why wouldn't the military just turn their encryption keys back on so that they can use it but others get worse data? I do agree that teaching your officers celestial navigation is important, but when shit hits the fan, it will be interesting to see which ones actually retain it and can use it without constant practice.
Even without gps computer vision should be more than capable of navigating via stars today. Shutting down gps is not going to stop missiles or anything else that would rely on gps very soon.
I appreciate the value of a backup navigation system if the electronics stop working. But so many things depend on GPS nowadays that there's a good chance some software bug would disable the ship anyway.
Even if it is a useful thing to learn, I don't see why everyone should have to learn it. It is like teaching graph theory to everyone in a university. Save it for the math and CS majors, and let everybody else learn something relevant to their specialty instead. Only those officers who will potentially at some point perform navigation should learn it. There are lots of totally unrelated specialties in the Navy where an officer can make a career: weapons, engines, aviation, medicine, etc. and others that are only tangentially related, like communications or radar/sonar.
How do you navigate a submarine by the stars?
I wonder how much this can be automated. Seriously, I bet it's fairly easy to program a software that takes a picture at night or of the sun and guess where you are.
Video of some good progressive thrash music
But is there really any point in knowing how to navigate by the stars in a world of GPS? "In the event that we had to go into a national emergency...
National emergency?
Just my 2 cents, but you should have to train a dog to mind you before you have a child, and you should be able to navigate by the stars prior to being allowed to use the GPS.
Happiness in intelligent people is the rarest thing I know.
Ernest Hemingway
Even if they didn't shut down GPS in a conflict it's ridiculously easy to jam by the enemy and highly susceptible to EM disturbance if nukes are involved.
For all intensive porpoises your a bunch of rediculous loosers
My son is an officer on a Naval supply ship and his coast guard certification as a 3rd mate required extensive testing on both terrestrial and celestial navigation.
Not sure what the difference can be with the Naval Academy. But lots of seaman are still being trained in the art.
If the federal government keeps slicing away at our capability for space flight then at some point we might see Navstar GPS fail merely due to lack of maintenance. Ground based radio navigation has been losing support due to the success of Navstar and other GPS systems. Having the US military rely on foreign built navigation systems just sounds like an easy way for an enemy to add confusion in a battle.
The nice thing about ground based radio navigation is that they are easy to maintain, no need for a rocket that can reach orbit. The bad thing about them is that they make easy targets. So if a nation can figure out how to take out Navstar then they can handicap the US military. In the absence of GPS and radio navigation beacons one would hope we'd still have enough people smart enough and knowledgeable enough to find other means to navigate.
This doesn't necessarily mean celestial navigation is the answer but that is probably one of the most reliable and accurate means we have available outside of GPS. Any radio transmitter can be used as a radio navigation beacon, just so long as you know where that transmitter is located, and enough smarts to operate a radio. In fact radio transmitters were used in WWII as beacons for pilots flying from California to Hawaii. Normally radio silence was practiced on the islands so that the Japanese couldn't use them as a navigation aid either but getting bombers safely to the air base was seen as a priority, and therefore an exception to the rule.
Using a commercial radio station as a navigation beacon did several things for the US in WWII. The radio station already existed, so no additional cost for the military. If you are going to transmit something then it may as well transmit music that is soothing to the flight crews as well as the general public. It also didn't broadcast that flights from the US mainland was underway, only that radio silence was lifted for some reason which could mean a lot of things. In modern times, during a real war, I expect creative aids to navigation to pop up like this. However, this isn't the 1940's. Any potential enemy we have today is going to have the technology to take out radio transmissions with greater ease than the Japanese Imperial Navy.
I am armed because I am free. I am free because I am armed.
On the 1991 cruise I was on when in the Navy, our ship's GPS went out. No way to fix it. We had to use compasses and star charts till we got to Pearl Harbor so it could be fixed. If the guys hadn't been trained for it, we'd have been screwed.
Is the Sun Coming up?? then put it on the LEFT!
Yep. And it is fun. You can pick up a $20 sextant off Amazon to play with (although you'd be better off with a more serious instrument). Like typewriters and other analog tools it slows you down and makes you think.
Celestial navigation, depending on the method used (and there are various)........ requires a very accurate knowledge of what time it is at the instant an observation is taken. Before GPS we used the time signals from WWV and WWVH to know accurate time, a necessary part of the equation...and a necessary part of being able to get both accurate sights that would yield accurate latitude and longitude. Many years ago before the advent of accurate shipboard chronometers mariners used a technique called lunar distances to try to estimate longitude and an idea of time--- via measuring angles between the moon and other celestial bodies. A local apparent noon sight yields accurate latitude but longitude is tougher. Presumably along with the GPS being jammed or destroyed or non operational for whatever reason, the reception of the WWV signals would go away as well. That would necessitate an accurate time standard shipboard- one not tied to GPS reception. 20 years ago ships carried mechanical chronometers in gimballed cases that were synchronized to WWV daily and a rate sheet- how much error there was.....was recorded.
I also subscribe to the comment about the necessity of being able to practice celestial navigation if need be. Just out of the classroom navigators arent going to be able to get decent sights for a while. Studies done years ago show that for any individual the first 500 sights are generally garbage for any number of reasons-- motion of the ship. mishandling or misreading the sextant, mis figuring the time at the point the sight is taken, misidentification of celestial bodies &c. So there is a lot to it-- however with a basic knowledge of spherical trig(one of the methods not using various tables), not much else is needed in the way of technology provided you know what time it is. Celestial navigation is an art as much as the practice of steps needed to identify and measure the altitude of a celestial body above the horizon, and translate the measurements into meaningful position information on a chart. Each sight of a body whether a star, planet, the moon or the sun, yields one line that goes on a chart. sights of 2 separate bodies yield 2 different lines- they are actually huge circles- circles of equal altitude- and where they cross is your position. A practicing celestial navigator will take a minimum of 3 and most times 5 sights of different celestial bodies to obtain a position. Takes an unobscured (not many clouds) sky and a defined horizon- so many sights are done just before sunrise and just after sunset. Its an interesting practice.
Analog instruments in a typical aircraft "six pack" are quite useful when in the air but mostly useless if floating on water. About the only useful instrument of those would be the magnetic compass. These instruments are also only useful in getting a rough position in the air, close enough to get within visual or radio range of an airport. When on the water one's visible distance is greatly diminished, and in a time of war one might not want to broadcast their position with a radio.
Also, who says that the USNA does not also teach how to use instruments similar to that on an aircraft? I expect that they do. I suspect that those are also just as fragile as GPS in a time of war. Celestial navigation is cheap, readily available, and impossible to "jam", so long as you know how to do it.
You might think it "utterly retarded" but people smarter than both of us disagree with you.
I am armed because I am free. I am free because I am armed.
On the 1991 cruise I was on when in the Navy, our ship's GPS went out. No way to fix it. We had to use compasses and star charts till we got to Pearl Harbor so it could be fixed. If the guys hadn't been trained for it, we'd have been screwed.
Exactly. Tech can fail or be disabled, either deliberately or due to enemy action. Remember how Russia was testing their GPS jamming tech against the US a few years ago in the middle east, by providing it to one of the countries we fought? Similarly, Iran used GPS to bring down a drone. Our guys need to be able to get by without it and, for that matter, to confirm that the computer is right.
It's not like we're requiring every enlisted man to know this stuff--but the officers on a ship of war should damn well know how to navigate by the stars if they have to.
Unless it's cloudy then you're fucked.
A bullet may have your name on it but splash damage is addressed "To whom it may concern."
Not if you have a "sun stone". The Vikings used them a few years before I was born. Yeah, I'm that old.
Yep. And it is fun. You can pick up a $20 sextant off Amazon to play with (although you'd be better off with a more serious instrument). Like typewriters and other analog tools it slows you down and makes you think.
The "makes you think" part is what's really important here. Thinking leads to understanding ... sounds pretty valuable to me.
First off you should never completely trust your computers. What happens if a software bug or a hardware problem occurs and says your 10 nautical miles west from where you really are? Not likely but still always good to check to make sure that your systems are running correctly.
The other reason is what if something happens to your ship and you have to abandon it before a distress call could be sent. Quite possible in times of war. You would want to know how to locate where you are so you could paddle the raft in the right direction (if you had a map or knew the location of land) or had some form of communication.
No, I think that would be a bit higher on the scale.
How can I believe you when you tell me what I don't want to hear?
Yes, all Navy ships carry sextants, accurate timepieces, and paper charts. You would be a fool to go out to sea without them.
The SR-71 had astro internal navigation long before GPS. This system required quite a bit of calibration at pre-flight, but with the sensors we have available today (gyros, accelerometers), this could easily be added to ships. This system can work day or night as well. It is pretty ingenious. There are several commercially available versions which could easily be incorporated into ships or drones. CelNav is a great exercise in math, but if your ship gets hit with an EMP, knowing your location won't do much good since you won't be able to move the ship.
You can get a sextant at Harbor Freight for $20, $10 on sale. This is the Chinese military issue version.
Decades ago, I worked in the TACAMO aircraft, the older KC-130 version. TACAMO was a US Navy aircraft charged with maintaining communications with nuclear submarines in the event of nuclear war. The aircraft had a small "sunroof" and it's sole purpose was to allow the navigator to see the sun and stars so he could use the sextant that was part of the issued equipment. The idea was that there would be no radio navigation aids left when their mission was over and they had to return to ... well anywhere they could land since the survival of any airbase was not guaranteed.
As an avid backpacker, I'm amazed how often recent enthusiasts I've come across have little or zero/map and compass skills. Sure, your GPS on your iPhone and hiking app are great, IF you have power, and if it's accurate. But if you lose it, break it, battery dies, then what?
I still travel with Trails Illustrated maps (or other topo maps) and a compass whenever I'm in the backcountry.
I think the Naval Academy made the right decision.
'The unexamined life is not worth living' - Socrates
"In the event that we had to go into a national emergency, we would probably have to shut the GPS down because it can be used by potential enemies," says retired Navy Capt. Terry Carraway."
When the shit hits the fan against a capable enemy ( cough. . . China . . . cough ) the first thing they're going to do is target all satellites considered military assets. GPS, Sigint and recon systems will be the first to go down.
If you, or your weapons, rely too heavily on such things, the War will be a very short one.
There is a very good reason modern weapons systems still have alternate guidance systems. In a GPS denied environment, they would be useless without them.
Assuming it's cloudy, you're GPS systems just went down, all radio navigation aids are lost, and all your compasses were demagnetized, then, yes, I assume one could say they are fucked.
One solution to this problem is like what reboot246 says in a sister post, have a sun stone as part of the celestial navigation gear. Another is to sail into a best guess of a safe direction until one can see a point of reference, be it a celestial object or terrestrial one.
Celestial navigation is not supposed to solve all navigation problems. What it is supposed to do is reduce the reliance on GPS to the point that should it go down you don't have a navy full of ships that can't so much as steer towards a safe harbor.
Having talked with people that sailed at sea, both for pleasure and for the US Navy, every ship has a number of readily available means to navigate. GPS is typically the primary means. Second on the list is likely to be radio navigation of one type or another. Third is typically dead reckoning. If you know where you were, what direction you are heading, and at what speed, you can usually keep sailing with relative safety and ease until you can restore one or the other means of electronic navigation. Those knowledgeable of celestial navigation can go without the electronic navigation for much longer and still reach their destination as scheduled. If it's cloudy while you are without electronic navigation aids then, yes, you will most likely arrive behind schedule.
In war you may not have the luxury of reaching your destination late.
I am armed because I am free. I am free because I am armed.
When I was learning Celestial Navigation, there were two sets of 'Almanacs' we had to use. One was the Nautical Almanac which gave the positions of the stars, the Sun and the Moon for each minute of each day of the year. These were issued every year by some National Observatory. The other set was just a cookbook of spherical trigonometry. Obviously you can program any modern calculator with the appropriate trig formulas so the Midshipmen would not have to waste time looking up those numbers in the books. I am pretty sure that with modern memory you could put the entire almanac for the year on a USB stick, and so you would not need to look up those numbers either. Add the two together and you can have a rugged, solar powered device that can do the calculations for you. Now all you need to do is get out your sextant and clock, take the sights, plug in the time, the readings and the corrections, and let the pocket calculator do the grunt work.
pgmer6809
Wow. Just... wow. Of all the things I wrote you focus on a typo I made in the first line. Did you even read the rest of the post?
I am armed because I am free. I am free because I am armed.
The enlisted guy whos title I forget who actually does the navigation has always been trained in astro nav. Teaching the officers is basically a back up they realize they need again.
OMG Ponies!!! with Glitter!!!! I miss Pink
This isx utterly retarded. Pilots learn to use analog instruments, I'm pretty sure the navy has enough back ups. Just seriously, get in the sea
http://breakingdefense.com/201...
The last few generations have come to rely on technology. If the tech breaks, YOU are fucked. The boys and girls who understand physics, and have studied the ancient arts are a lot less fucked, so they might survive to fuck each other.
"Windows is like the faint smell of piss in a subway: it's there, and there's nothing you can do about it." - Charlie Br
You're thinking of the cock's son?
https://en.wikipedia.org/wiki/...
"Windows is like the faint smell of piss in a subway: it's there, and there's nothing you can do about it." - Charlie Br
Celestial navigation was taught in our Naval Science Navigation course. As naval bridge officers, we were required to learn celestial navigation primarily as tradition and to have a working understanding of the mechanics of the process. That being said, one must know where the ship is at all times. Today, we rely on GPS, inertial navigation systems and the gyroscopic compass (as opposed to a magnetic compass). There have been times when we lost GPS or LORAN C while at sea. We did experience loss of the gyroscopic compass in the middle of ocean and our ship didn't have INS. You have a mission to carry out and that entails safely navigating your vessel.
Basic skills such as dead reckoning and visual position fixes are used when near land. At sea, with no landmarks, knowing where you is just as important. Case in point is that there is an underwater mountain in the Pacific that ships still manage to hit. Avoiding those things is pretty important. Murphy's law will ensure that your ship fill find the underwater mountain or shoal waters if you aren't prepared.
Do navigators take celestial fixes every night the skies are clear? No. They do it from time to time to keep the traditions alive. And, should the skills ever be needed, they will have them. The calculations are tedius and no where as accurate as GPS fix. But, it's an interesting exercise and a time honored tradition.
My mostly ignorant opinion manually filling out forms and digging thru sight reduction tables is a pointless exercise.
I think a backup for GPS is worthwhile but all people really need is some experience using a sextant and reasonable ability to quickly spot nav stars and input measurements into a computer. Alternatly use a star nav system that will automatically and accurately compute your position based on image capture of the sky.
No matter what you'll still need an accurate clock to get a fix so there is still some reliance on technology which constrains the cyber/attack/disaster scenario one is able to dream up as justification.
THIS thread, all the way back to the AC. You guys get it. Any slashdotter worthy of the name would get navigation in an afternoon. I spent two weeks on a boat crossing an ocean and in that time nailed every observation in the book: sun-run-suns, noon sights, compass checks, planetary observations, moon sights, 7-way star fixes. The calculations are straightforward, the only required input data that you can't work out by hand is the celestial ephemera. But even if the almanac went overboard, a sextant, the sun and my casio F-91W wristwatch ($15) would get me across an ocean to a landfall.
I'm an officer for the Royal Canadian Navy. I've spent time on the bridge of some of our American friends' warships and it's sometimes a white-knuckle experience. Sailing into northern waters away from large constellations of GPS satellites can easily bring your dilution of precision to the point where you could be almost anywhere, and yet many of my American friends didn't even know what the reading meant on their display. HDOP would be flashing red on the bridge and they would be all fat and happy sailing at full speed. ECPINS put a dot on the electronic chart as to where they were, so that meant that's where they are.
It was with puzzlement that I first learned that Americans didn't teach celestial navigation to its officers. It's not that celestial navigation by itself is really all that necessary, because yes, even without it, there are other methods. But the training of it produces officers that have a better understanding of when their machines are lying to them. It, and all the related skills you need to learn to make it work, gives more useful things in your toolbox to draw from. Because I will tell you from experience, it is not a matter of if a GPS will give you a wrong answer. It's a matter of when.
It's also, if you ask me, not a matter of if but when a shooting war finally breaks out. And if and when it does, you can guarantee that one of the first priorities for the enemy will be to deny NATO (one way or the other) the use of GPS.
Perhaps with a renewed focus on training techniques that don't rely on toys, the USN will stop having the most collision-dented ships in NATO.
You can find a good amount of information online--this is a good place to start--and yeah, a lot of its basic uses doesn't require much math, especially if you're mostly using it to check your dead reckoning work, which is always a good idea. Part of why people developed celestial navigation in the first place, and why it was so important, was because dead reckoning was not reliable enough; every so often you found yourself in places you didn't want to be, including 'Middle of the !@#$ Ocean' and if you were really lucky and had somebody aboard who knew celestial navigation you could at least figure out where to go to reach land before you died horribly.
Someone mod the parent post up.
HDOP would be flashing red on the bridge and they would be all fat and happy sailing at full speed.
In the middle of the North Atlantic what is there to hit?
Perhaps with a renewed focus on training techniques that don't rely on toys, the USN will stop having the most collision-dented ships in NATO.
Oh, yeah, you can hit other ships in your flotilla.
At least you still consider us your "American friends".
I am armed because I am free. I am free because I am armed.
In the middle of the North Atlantic what is there to hit?
That's exactly what the captain of the Titanic said!
Not if you have a "sun stone". The Vikings used them a few years before I was born. Yeah, I'm that old.
Leif Erikson I presume? When I read your message something in my mind whispered, "calcite" and whaddaya know, it was correct! Check out the science behind it. P.S. when you landed on Erika (mis-named America) did you see any golden arches? I've always thought they were some natural feature, and people later decided to build restaurants under them.
<blink>down the rabbit hole</blink>
Military GPS accuracy = 0.001 nm (a few yards).
Inertial accuracy = 0.1 nm / hour degradation
Celestial navigation accuracy = hundred nm
So unless GPS is gone for days, inertial is still better
That's a result of USA getting rid of LORAN which before GPS was the primary update source for inertial systems, and after GPS was fully operational switched to backup.
Celestial navigation is pretty much strictly a means to getting to the nearest port. Very limited usage for combat operations.
Thank you Sir! Very well said. I am a 68 year old American engineer (retired) who learned his craft using a slide rule and trig tables. During my career I worked with almost every type of computer from Analog behemoths to microprocessors and the one thing I learned is that COMPUTERS WILL LIE TO YOU. You just have to know a bit more than they do to catch them at it.
Also, I wonder if this move is not so much about just loss of GPS but loss of a lot of our electronic infrastructure due to Electromagnetic Pulse, whether man made or from natural events on the Sun. I know of engineers in the US currently working with some of our electric power companies to make contingency plans for such an event. Should we expect any less of the Navy?
Wow, you found mathematically perfect lenses that do not have any surface imperfections?
A manufacturer that can guarantee zero alignment error (even down to the nanoradian!), and a crack team that can design for absolutely no thermal expansion/contraction problems?
A lens form for vanishingly-near-zero aberration (Certainly, someone of your intellectual caliber would, after all, know lasers have variations from their stated value due to manufacturing flaws), and constructed from a material that has near perfect transmittance in the given wavelength of laser?
Please, do tell me how you will manage to correct for the small but nonzero amount of atmosphere at high altitude, which would also introduce diffraction that would have to be corrected for in real time to hit the target with that 'microns wide' beam while also attenuating the amount of light from scattering and absorption.
I'd also love your opinion on spacecraft thermal management, and how you'll put this umpteen-kilowatt laser in orbit and fire it without melting the laser discharge tube, the metal holding the tube, the optics focusing the beam onto a microns-thin point that'll put even more thermal stress on the spacecraft's optics than the target's own, and also how you'll fire it without melting the rest of the spacecraft. Furthermore, I'd like to hear how this thermal management solution, laser, optics package, and spacecraft bus will be small and light enough to fit on a small, lightweight military booster that can be launched on a moment's notice without providing warning to enemy state actors to attract cruise missiles or other ballistic bombardment.
Please try to keep up, here. I'm genuinely curious.
A GPS wouldn't have helped in that case...
Non-Linux Penguins ?
Wow, you found mathematically perfect lenses that do not have any surface imperfections?
Old tech, actually. Spy sat use lenses that change dynamically to compensate for the atmosphere, turbulence and all, in realtime. The same tech works fine for laser weaponry, and was part of the Airborne Laser plan. Merely being a good lens in a vacuum is easy by comparison. I suspect this isn't the limiting factor in hitting a satellite 20 km away with a laser - it's payload cost. I'd bet it's cheaper to get a payload to GEO than build a laser weapon capable of hitting a target like that with it's onboard guidance. The problems may all be solved, but's different from solved cheaply.
Socialism: a lie told by totalitarians and believed by fools.
It's worth noting adaptive optics for a camera isn't the same as trying to focus a laser beam onto a tiny point thousands of kilometers away. The shape of the earth's atmosphere is somewhat forgiving anyways, from outside-looking-in. It refracts light to a point instead of diffracting outward, for one thing. Then, there's the matter of just looking at light bounced off the sun instead of trying to take a laser designed to melt things. Here, you have the problem of trying to focusing your infrared doom beam onto a point using onboard optics, without melting things where you don't want them melted. ie: your onboard optics.
Trying to focus your infrared doom beam, even.
America was called Vineland by the Vikings ;D but that golden arc thing is a mystery to me as well.
For some reason they are here in Europe now as well!
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
In the middle of the North Atlantic what is there to hit? ... (that is an 'island' and a country, perhaps you want to look it up)
Island for starters
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
The ABL project apparently solve this well enough for in-atmosphere to in-atmosphere as considerable distance, for the specific problem of focusing laser weaponry. Everything's classified of course so I can't say for sure.
A focusing lens in a vacuum for a mere 20km just isn't that hard of a problem. Other problems will dominate, including finding the target in the first place if it's a stealth military sat and not a telecom sat. I rather suspect you could build a ground-based laser to take out a telecom sat, but I think we'd know if anyone had, so that orbit seems reasonably safe for now, short of nukes (which of course would get used in a real war, rendering this whole discussion moot).
Socialism: a lie told by totalitarians and believed by fools.
I'm surprised they even stopped. I mean, common sense would tell you that electronics can fail for one reason or another and you should have a backup. (I have backups for everything) I assume they don't teach Morse code either. I mean, don't spend an entire semester on these things, but at least the basics or a crash course.
Yes, that system was called LORAN, and we shut it down a few years back to "save money":
US Navy ships (and most commercial ships) have multiple backup systems. One is the shipboard inertial navigation system (SINS), which is entirely self contained once you tell it your current location. It is accurate enough to find Tokyo after leaving San Francisco if you lost GPS, LORAN and all other forms of electronic navigation. I recall reading that the current generation would be off by no more than a mile on this voyage. Since the 1940's there is the DRT (Ded Reckoning Tracer) [No, "ded" is not misspelled - it is a shortening of "deductive"]. This device was on US Navy ships during WW II; like SINS it needs a starting location, but it then monitors ship's motion to project the course on a chart. It is still carried as backup. The "ded reckoning" part is because it cannot account for currents, so errors will accumulate, and it needs to be recalibrated using either landmarks or celestial navigation. It also needs to be recalibrated when you go off the edge of the current map. There are also classified VLF systems, used mostly by submarines. The point is any military service needs multiple backups. In spite of sophisticated telephone and data systems on modern ships, they all still have point-to-point sound powered phones and voice tubes.
I think you meant Ireland or maybe Iceland? Both fit the description...
Or, maybe you are Icelandic, where they apparently call Iceland, Island.
He didn't call you a GPS system. He called you GPS systems - plural, with no article. Be insulted correctly, dude.
It was with puzzlement that I first learned that Americans didn't teach celestial navigation to its officers. It's not that celestial navigation by itself is really all that necessary, because yes, even without it, there are other methods. But the training of it produces officers that have a better understanding of when their machines are lying to them. It, and all the related skills you need to learn to make it work, gives more useful things in your toolbox to draw from. Because I will tell you from experience, it is not a matter of if a GPS will give you a wrong answer. It's a matter of when.
This,
Its not about teaching them how to use a sextant, rather it's about teaching them how to think for them selves.
There will be times where their only navigational aids will be basic, magnetic compass and the old MK I human eyeball. In peace time as well as wartime (although in wartime, it'll be a lot more common).
This is why the European system, the bloated, expensive and over engineered Galileo (GNSS) operates on it's own frequency as well as that used by GPS and GLONAS (Russia). You can block Galileo without blocking your own system.
Calling someone a "hater" only means you can not rationally rebut their argument.
You are asking a lot of an anonymous coward whose brain seized up when confronted with a typo/egregious grammatical error. Next you'll be demanding they take responsibility for their venom, which will also not happen.
--- Say something clever. Pretend it was me. Thanks.
And hardware never fails, cosmic rays never affect memory, and programs never terminate unexpectedly.
Best comment of the story.
Someone who's too young to remember the fdiv bug.
Have some real fun. Make your own. THEN buy one off Amazon.
http://solarscience.msfc.nasa....
With polaris or the sun and a straight edge and a string (or your hand at arms length), you can make a reasonable landfall.
Iceland, I just typod again as Iceland is written Island in German ;)
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
Analog instruments in a typical aircraft "six pack" are quite useful when in the air but mostly useless if floating on water...
The altimeter will double as a barometer.
When all you have is a hammer, every problem starts to look like a thumb.
You've been on the bridge of US warships -- I have not -- but I wonder why inertial navigation has not been installed to serve as a backup at least on capital ships.
Consider the navigation of nuclear subs. They may serve for months silently submerged. They can tow lf antennas, but they need to navigate in real time, and even semi-reliable techniques like sonar pinging the sea floor would enhance enemy tracking. I've heard that subs have well-developed inertial tracking for reliable navigation over nontrivial time periods. I'd like to know more out of intellectual curiosity.
If inertial navigation works well enough, why isn't it also available on a $1e9 capital carrier?
Inertial Navigation Systems are good pieces of hardware, and without giving anything away I can tell you that you can assume most major warships in any of the better NATO navies will be equipped with it. However, no unit (surface or submarine) relies on it as a principal means of navigation, certainly not for months at a time. It is a system that starts out accurate and gets progressively less and less so as you go, especially in rough seas. Remember, it has to add up every bit of inertia in every direction - including wave motion. By the time you reach your destination your area of probability can be so large that celestial navigation (using modern instruments) can actually be more accurate. INS has to be periodically corrected, and when GPS isn't available or is degraded (or we are training without it), this is done by old fashioned traditional navigation methods. Fixes based on visible features (land, nav markers), celestial fixes, bottom contour fixes, etc. It's bottom contour fixes using depth sounders that submerged vessels use as their primary means of navigation.
INS does have its uses. And while I can't discuss when and what situations would call for its use as a primary means of position fixing, it probably shouldn't be too hard to work out likely scenarios. Traditional navigation is still king. INS is only used as a primary means of navigation by the authors of war novels.