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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."
Astro-inertial navigation is old tech for missiles. There's no reason that someone couldn't slap together a similar system as backup for guiding a ship in lieu of GPS. That's not what this is about. This is about weeding dumb people out of the Naval Academy.
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.
What if the issue is not lack of GPS but lack of electrical power? Or, in the case of an EMP, the computers are scrambled? In the time it takes you to work out the issues with the electronics you can also have some people trying to figure out where you are by celestial navigation. That means less down time.
Also, how do you know the computers aren't lying to you? In a sophisticated attack the navigation may not be down but merely rendered inaccurate. Having celestial navigation as an aid means you should be able to correct for electronic navigation errors more quickly.
Also, electronic navigation may only provide one or two points in a triangulation. To complete your triangle of points one might want to know something as simple as which way is north. Reading a compass might seem trivial to you but for some young sailor fresh out of the academy that might not be trivial. Add to that some basics of dead reckoning and just some theory on celestial navigation then we have someone that can get back into the fight more quickly than a sailor ignorant of these things.
I am armed because I am free. I am free because I am armed.
Not if you have a "sun stone". The Vikings used them a few years before I was born. Yeah, I'm that old.
Allow me to introduce you to the ships gyro. Also referred to as a stable element.
It's the reference plane the fire control systems utilize while plotting a firing solution for the ships guns.
Some of the older manned directors also referenced them and kept the director perfectly stable even in rough seas. Was the best place to be in the event you and the pitching seas didn't get along :)
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
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.
Mind you, there's a significant difference between hitting a satellite orbiting at slightly more than 300 miles up, and hitting one that's 11,000 miles up.
A lot of the low-earth orbit satellites - which includes some reconnaissance satellites - are vulnerable to common fighter-launched ASATs, but hitting something in geosynchronous orbit is a bit more difficult. It would take large ground-based rockets to reach that altitude, and you would have to launch at least six to disrupt the GPS system over a particular area (and even then, the results would be only temporary as the network can compensate for some losses). Even ICBMs aren't powerful enough to reach them; you would need liquid-fueled rockets that need to be fueled up prior to launch (you don't just keep that stuff sitting around in the rocket's gas tank indefinitely) prior to launch, so your preparations would be very visible and very vulnerable. GPS satellites are also traveling at more than 10,000mph, which makes them a tricky target to hit, so you'll likely need to launch more than one rocket per satellite to ensure a successful interception.
It's not impossible but it is difficult and probably more costly in resources than it is worth.
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.
Navigation will be the last of your worries then.
Being up shit creek and all I had was a paddle I'd think that knowing where I was would be the first concern.
Let's gather the situation here. Communication is down, weapons down to .50 M2 and small arms, no GPS, no power. Since the ship is likely steam or gas turbine powered the crew should still be able to get the ship to move. I presume as well that there are crew that are injured. This crew is also going to be in need of food, heat, and shelter. I'd think that what a wise captain would want to do is head for the nearest safe harbor for repairs. At a minimum getting to port would mean the crew can find food, heat, and shelter until the ship is repaired or they can be picked up in another.
Given that situation what should a captain do? Head to safe harbor, right? Okay then, to get there they will have to be able to at a minimum know which direction to sail. With a watch, compass, and charts one can do wonderful things. With a sextant and the knowledge to use it, miracles can be performed.
I am armed because I am free. I am free because I am armed.
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?