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US Coast Guard Intends To Kill LORAN-C
adaviel writes "LORAN (Long Range Aids to Navigation) is an electronic navigation system using low-frequency radio, used by many boaters (including me) before GPS. It has an approximately 200m accuracy and is a functional replacement in case GPS fails or the US implements selective availability in time of war. The US Coast Guard, part of the Department of Homeland Security, intends to turn it off starting February 8." This is in spite of $160M spent on modernizing LORAN stations over the past 10 years.
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And on top of that, other GPS-like systems are being built. Yes, Galileo has been delayed, but it will eventually be launched nonetheless. And it's not the only one.
Linux user since early January 1992.
"This is especially idiotic considering GPS satellites that are currently in orbit are beginning to fail, and no country wants the responsibility of modernizing them, or repairing them."
Okay...
1. The DOD depends on GPS and matains the network. So what are you talking about countries wanting to take responsibility for the GPS network? The US DOD does.
2. You do not repair or modernize GPS satellites... You replace them.
3. GPS is going to keep working until it is replaced with something else or the US stops being a nation.
"Further, what if a GPS receiver goes offline on a ship?"
You use the backup? You don't really think that a ship would only have one do you?
The reason to keep both was that many operators spent a lot of money on Loran and GPS was expensive. Now GPS is cheaper and more reliable than Loran.
Your arguments are along the lines of "We should keep paying for hitching posts on our streets so we can keep horses as a back up for cars."
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
200m is the absolute accuracy (and is a bit pessimistic). The repeatable accuracy is much better.
That is, if you sail into a port's harbour channel and save that as a LORAN-C waypoint you will typically be able to get back to that same spot within 20m or so easily.
SA made GPS accurate to 10m.. With the "SA" feature disabled, you're down to 2m... And with Satelite enhancements, it's more like 20cm !
But that's irrelevant.. Because SA was intended to disable any enemy force from using GPS for accurate positioning - until they realized D-GPS (Differential GPS) made the whole point moot (you take a reference point - you send the signal to the receiver - And therefore - the receiver can deduce the SA introduced clock error - because now you have a ref point .. And believe it or not - it is a United Stated Uniform service - the US Coast Gard - that came up with it to overcome the artificially introduced uncertainty).
However, the military still keep exclusive use of the 1Mhz band (with the 10Mhz being public) - for the only purpose of being able to make real time measurements on tropospheric distortions - so - what happens - is that the military can make 1m accurate reading WITHOUT sat aids.
Actually, yes. When I was commercial fishing on a troller in Alaska we used Loran grid coordinates, spoken in Danish, to tell our brothers where the fish were. No one else could understand us. If we said "Over and out" the conversation was finished, but if we said "I'm off," that meant to change frequencies, tell how many King's you'd caught, and give the coordinates. Without the Loran our sneaky ways will have to be changed.
How about a moderation of -1 pedantic.
At least my recollection is that while the absolute accuracy of LORAN isn't nearly as good as GPS, it actually had better repeatability (i.e. the ability to return tomorrow to that fishing spot you found today) than at least pre-DGPS/WAAS GPS did.
Today's modern GPS systems and supplemental accuracy aids probably make this moot, but it's a major reason why LORAN has survived as long into the GPS era as it did.
G.
Frankly, I'm surprised this is still around. Everyone I know has switched over from LORAN-C to GPS or other systems at least a decade ago. Even aside from the cost of maintaining the system to the government, the system is clearly inferior to GPS. For one, since the towers are much lower compared to satelites, it is much easier to have your signal blocked. The system isn't nearly as accurate (as mentioned in the summary) and is also in many contexts much more likely to simply fail. The system also doesn't work if one is far away from land. This is an extremely reasonable cost-saving measure.
In my pilot weather briefings, I routinely get notice that one of the satellites (GPS-25, I think) is out of service, and I think GPS-30 showed up in a briefing recently, too.
You can never go home again... but I guess you can shop there.
I visited Cape Race, NL which has both a LORAN-C station and a DGPS station. Looking at the two I don't blame the USCG for getting rid of LORAN-C, the LORAN-C has a nice & large radio tower, as well as a giant room with huge motors spinning around, mainframes that look like they're from the 60s. And since it's so far up North, you have to heat the room in the winter and cool it in the summer. On the contrast, the DGPS site was a couple of racks in a trailer. and 4 6m-ish towers around it. The heating cooling costs are much less and most of the maintanance is just scraping the snow/ice off the towers when it snows :-). Combine this wit the fact that no-one really uses LORAN-C anymore, it's not hard to see why
500m accuracy for sextants seems unrealistically good to me. My experience is approximately 2km in good conditions and with an accurate clock available. But even that is good enough for navigation.
I've been a sailor most of my life. We haven't used Loran C seriously for almost two decades. Most boats don't even have Loran receivers any more. It's GPS all the way whether you are a casual sailor or a commercial ship captain. In fact, large commercial ships are required to use GPS and special transceivers these days (the boater's equivalent of GPS-based aircraft systems). If backup matters one could pack a RDF or maybe even a sextant, but frankly GPS has not failed even once from the day it became available to boaters. Besides, Loran C pretty much only works near the coastline of major industrialized nations (or did)... it wouldn't be all that helpful if you were lost at sea.
The coast guard should have abandoned Loran C years ago.
-Matt
Does it seem stupid to anyone else to disable all of the lower-tec nav aids? What if some crazy decides to use anti-sat missiles and take all of the GPS satellites out or as in COD MW2 detonates a nuke in space to disable all communications?? I guess we can just go back to using sextants if that happens...
Loran A that I was using around 1970. In mid-Atlantic you couldn't get signals during the day and accuracy was around 1 nm, but it certainly was nice to have.
"Do the Right Thing. It will gratify some people and astound the rest." - Mark Twain
It has better *resolution* than that, although I can't speak for the accuracy (meaning repeatability).
Back in the day, I actually rigged up a Loran system and a surplus Compaq Plus luggable computer in my car, and wrote a program in QuickBASIC to log lat/long data points while driving back to college from vacation. Just to see what it would look like, I drove completely around a cloverleaf interchange (four 270-degree turns), and continued on. When I got where I was going and ran the data through a really cheapo plotting program I wrote, I could clearly see all four loops (some a little flattened, probably more due to the 1-second time resolution than anything.)
Granted, this was in the middle of nowhere (low noise), at night (nice propagation), with a long whip antenna on the top of the car -- but it was still impressive for Loran-C. (And yeah, I know it would be a piece of cake for any half-decent GPS receiver.)
As for selective availability, I think this could be implemented over Loran -- although Loran's repeatability without modifications is probably no better than the ~50m accuracy of GPS+SA...
Paleotechnologist and connoisseur of pretty shiny things.
...They are shutting LORAN-C off because it's expensive to maintain a separate system, especially one that is not nearly as accurate as GPS, and is at risk of terrestrial attack...
But -- isn't the Loran C low frequency operation better able to punch a signal through periods of poor RF "weather"? During heavy solar storm activity (sunspots, peaking each 11 years) I hear it's sometimes kind of hard to get signals through, especially the S or K band stuff used for satellite communications. I remember during the Pioneer satellite days that it was sometimes quite a job for us to pull the signal out of the noise (clever use of FFT mostly). Satellites don't have huge power budgets. Larger antennae help, but you're still looking at a few watts at most.
And a submarine could still use Loran C if its inertial guidance system goes out of whack, without surfacing, I think, as I believe you can acquire a low frequency signal more easily at depth. In a worst-case situation, such as the massive EMP hit of a nuclear weapons discharge, I'd think that Loran would be back on line before you could read a satellite. Mind, we'd have worse problems, but I'd think the military would need to consider this sort of thing.
I guess it ain't sexy 'cause it's analog.
Do not mock my vision of impractical footwear
And your GPS satellites got blasted out of orbit or a solar storm wipes out all of those satellite resources?
Your SONET networks and cell phone stuff are gonna need it. Your 8-VSB exiter may as well. Single Freq. Networks.
Where do you get an accurate reference from?
WWV? I haven't seen anything other than a GPS reference at any telco facility/cell site. If there ever is a loss of GPS, it's gonna be interesting.
It's the end of an era I guess. This story throws me back to 1964, wandering the North Atlantic aboard HMSS Hudson, doing marine geophysical surveys.
When it came to positioning, we left nothing to chance; we had the requisite equipment (pre-computer), tables and charts for LORAN, DECCA, CONSOL and the brand-new, edge of the technical envelope, VLF. Sometimes we used a few of them together, with transparent overlays giving a very small polygon containing, somewhere within it, our little ship. We liked to brag that we could pin down our position within its length.
One of my favourite duties was radar watch and navigation, especially late at night, lights dimmed, phosphorous glow from both the radar screen and the froth on the waves ahead. Transferring readings from the radios and charting our course made me an integral part of the process, acutely aware of the immensity of the ocean around us and challenged to keep us from losing our way. I can still smell the mixture of diesel, coffee and ammonia (from the weather fax machine) that permeated the bridge.
Now, with the retiring of LORAN, it's finally all gone, replaced by an LCD display your grandmother can use. Sad.
I'm a Programmer. That's one level above Software Engineer and one level below Engineer.
>because it is a beacon based system that selective availability cannot be implemented over
You forget why selective availability was turned off.
During the years of Selective Availability, if you took your GPS receiver to a "known point" (like a USGS marker), you could adjust for the "fuzzing" (it wasn't a real fuzzing, it was just an offset) of the signal and get accurate readings anyway. This is known as "Differential GPS" and was widely used by people having an interest in using it (land surveyors, civilian navigation, etc).
Differential GPS made selective availability useless as a security tool.
Turning off LORAN isn't about being able to turn SA back on again. It's about costs.
--
BMO
LORAN coverage is very limited. ... Have a look at the map.
LORAN is in no way a useful backup for GPS except in a very small part of the oceans.Look closer at that map.
Take a closer look at that map. It goes out a goodly distance from the coasts.
They say that, in an airplane, you can do anything you want as long as you don't do it close to the ground. Much the same is true for boats and the shore.
If you're really far out in an ocean you can get back to a continent by sailing east or west until you pick up the shore. (If you've lost track of which set of continents is the desired target you're already in serious trouble.) Trips to another hemisphere from temperate latitudes are major undertakings. Northern hemisphere boaters tend to stay there most of their lives.
No sextant? You can approximate your latitude without a time-hack and even without a protractor you can hack up an instrument to get your latitude within a few degrees with a piece of string, a weight, and a random piece of something like a book or a cutting board. Get roughly to the right latitude (so you will get roughly to the desired port) use the instrument to compensate for north/south drift from currents, and sail east or west until you're within range of LORAN.
It's when you get near the shore that you're in trouble if you don't have something better than eyeballs - especially if you end up there after dark. LORAN can give you enough warning that you can safely rig the boat for unattended sailing and get some shut-eye without worrying about running aground when you find the continent. If GPS is down, LORAN is gone, and you don't have a sextant, a chronometer (or a radio to get a time broadcast), good charts, and a lot of training in celestial navigation, you'd better put out the sea anchor after dark. This about doubles your trip time so you'd better have lots of fresh water and provisions.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
"Without the Loran our sneaky ways will have to be changed"
Come up with a list of 100 words. Danish, Esperanto, Klingon, or whatever. Assign numbers from 00 to 99. Read off your GPS coordinates using one word for every two digits. Save time by pre-defining large grids with special names to avoid having to read off more digits than necessary.
I've got notes around here somewhere on a more sophisticated version of that I was playing with for search and rescue use - not to conceal anything, but to be more efficient and accurate than reading strings of numbers. The words were simple, of a consistent number of syllables, phonetically distinct (long Hamming distance) and with multiple lists you can make it tolerant of transposition of words. The idea was for the encoding to be done on a GPS receiver - you wouldn't need to do it manually.
As long as you have a decently accurate clock, you can get a lot closer than that without any externally-dependent navigational system.
Your mind is clear / The things that you fear / Will fade with how much you / Believe what you hear
The "new" version of DGPS is called WAAS (wide area augmentation system), which is where airports in the US will have local DGPS stations send their correction data to the WAAS satellite, and these corrections will be distributed to aircraft flying over the US for use as precision approaches (instead of the use of radio equipment at the end of runways).
Exactly.
SA wasn't even used in the gulf war. Its unlikely ever to be used because so much relies on it, and a Euro system or a Russian system would make it pointless.
It was never all that great (the claimed accuracy is optimistic), the receivers are hopelessly expensive and all commercial use has, for all practical purposes, ceased.
Even during SA use periods, GPS tended to be more accurate anyway.
Sig Battery depleted. Reverting to safe mode.
Knew a lobsterman who told me he'd steam for two hours, come up on his Loran set point - cut the throttle, stick his gaff out the port side of the boat and grab his trawl, without fail. In the dark. Sounds a bit better than 200 m. He had the lobsters to prove it!
The best hope of hitting this kind of targets would be lasers. However, I think only USA has lasers that maybe approach the level of power and accuracy needed to hit a target floating very fast at several thousand kilometers "up there"
You'd be astonished how badly sextants work in fog or in a rainstorm.
In September 1923 in pre-Loran days, the US Navy ran seven destroyers onto the rocks at Honda Point in California. http://www.history.navy.mil/photos/events/ev-1920s/ev-1923/hondapt.htm Those ships had plenty of sextants and navigators that knew how to use them. ... and they did not know where they were.
You can't see ANYTHING from a car, You've got to get out of the goddamned contraption and walk...Edward Abbey
Sure, SA was eliminated. But the US bitched about the Galileo system that the EU is making until they changed the frequency to one that was farther away from what GPS uses. The reason was because if they used the same frequency it would be impossible to jam Galileo without also jamming GPS. The US threatened to launch against Galileo satellites if they didn't change frequencies. The point being, if they were this pissed off about not being able to jam Galileo then they obviously have a way to jam Galileo if they deem it "necessary". It doesn't make sense to jam Galileo and at the same time run GPS at full accuracy, so they obviously also have a way to jam non-military GPS receivers. It might not be called SA anymore, but they have some method of jamming it.
-1 disagree is not a modifier for a reason. -1 troll, flaimbait, redundant, overrated are NOT acceptable substitutes.
Such solar "hiccups" have happened several times since the middle of last century. Some destroyed equipment on the ground -- and at those energies, nothing in orbit is likely to survive intact.
Well, even the ground (e.g. LORAN) equipment could (would eventually) be fried, so don't you think that only safe fall back technology in navigation is pre-electronic, classic astronomical and geomagnetic one? IMHO, we should use our improved and accumulated knowledge of materials, planet Earth and heavens above to construct better, yet still robust, aids for "passive" navigation.
There are also examples of quite amazing navigation done using sextants, particularly the voyage of the James Caird http://en.wikipedia.org/wiki/Voyage_of_the_James_Caird
You know that both GPS and Galileo (and GLONASS for that matter) include quite a bit of redundancy; it's unlikely that a significant portion of the satellites would be affected by any single event. And GPS and Galileo are easily interoperable, so a single receiver can use a combination of the two systems to get a fix even if any one system does not provide enough functional satellites.
I'm not saying it's impossible for the whole shebang to fail, but it's not nearly as likely as you'd like to pretend. Nor is traditional navigation nearly so helpless; it might take a few minutes for an inexperienced navigator to get a fix with astronomical observations, but it only takes 2 pages of cheat sheet, a 4th grade education, and a few minutes to use a sextant.
Well they can simply turn GPS off (entirely or over certain areas) or introduce large-scale errors; since they don't control Galileo that's not an option and jamming is the only solution. And since jamming is not a precision tool it would be nice if jamming operations didn't interfere with the more selective control available for GPS.
They're probably also worried about unintentional interference from Galileo. Or jamming from third parties -- if someone starts jamming radionav systems it would be useful to know if they're targeting the EU or the US.
On the contrary. The GPS constellation consists of fast-orbiting spacecraft. Period is about 11 hours. So all that must happen is an event that lasts 11 hours and has sufficient energy to do the job. The reserve sats (block IIR) orbit at the same rate; they'd be just as fried as the block II and block IIA sats.
For GPS to work, you need a minimum of three working sats within LOS of the antenna; the position fix is determined from the downward intercept of three spheres centered on the sats. Anyone who is depending on this, and suddenly loses it, may be in serious trouble. And it's not all that easy to whip out a sextant in the cockpit of an aircraft, or in your SUV (I'm really not sure how many expeditions actually carry a sextant, for that matter. I don't own one, and I do know how to use one.)
Here, take a look at this charmer, happened only 2 years ago: X-class flare. Pay particular attention to the duration.
I've fallen off your lawn, and I can't get up.
I've never used it on a boat but I went flying with another pilot once who had a LORAN unit installed in a Kitfox. I didn't even know what it was at the time, but as he explained it, it was much cheaper to install than a VOR receiver. We did a fair amount of flying in Florida navigating using that unit.
I know that with the prices of handheld GPS (for aviation, boating, and everything else) coming down a lot of such technologies may be shut off, but it still seems a bit sad to me. I love GPS and it certainly is easier to use, but I'd like to see some of the older technologies maintained at least as backups.
"People who think they know everything are very annoying to those of us who do."-Mark Twain