Loran is no longer in service, correct?

[tkamiya]

I see LORAN receivers every now and then.  Didn't LORAN station ceased service quite some time ago in most areas including USA?

[chuckb]

Yes, LORAN-C has been decommissioned in the United States. It may be active in other parts of the world. Everybody uses GPS today.
There are some videos on youtube of the towers being blown up.

[chris_leyson]

I think all of the Loran-C chains around northern europe have all gone. In the UK e-Loran was discontiued Dec 2015. I used to regularly listen out for Omega transmitters at 12 kHz and the one day they had all gone. Don't if the former soviet union Alpha transmitters are still in use. Also used to pick up Decca navigator transmissions but they've gone as well as Datatrak. I think South Korea are setting up e-Loran transmitters and e_loran may still be in use in India and Saudi Arabia. Edit: Russia and China are upgrading their hyperbolic navigation systems. It seems the UK government have changed their minds yet again http://www.maritimejournal.com/news101/onboard-systems/navigation-and-communication/uk-government-supporting-e-loran

[tkamiya]

I typically don't like to have a single point of failure. How WWVB is at risk of getting decommissioned, I guess GPS will be the only source.

[coppercone2]

I wonder if the army has a silo of GPS satellites ready to launch in case of war given the fact that they destroyed their loran system, a bunch of dormant GPS satellite loaded missiles might be cheaper to own as a redundancy then to maintain infrastructure that offers crappy accuracy.

Russia, India, China probably have much worse space weapons technology so they probably know other then a surprise first strike they won't be able to destroy the satellites efficiently when the air/space defense readiness level is raised and all the eyes are on the sky on the second or even third batch.. given the massive advanced missile destroyer count, and how spread out our airbases are (given the new air launched space interceptors you might be able to defend satellites from jets).

 I think public outcry would be much less if you destroy some robot satellites then when you start blowing up transmitter masts on their own soil that are crewed and civilian? run, so they have a kind of human civilian shield in place to counter heavy handed war-like sanctions like destroying drones and satellites used for positional signals.

Of course someone might want to fuck up space completely using some kind of mad plot involving needles or such (like Dr. Strangelove for satellites) , but that would put us back into the 1950's as far as communications go, save for some fancy new undersea cables.. and literary piss off every single first world country.

[rigrunner]

I've just fired my receiver up to check and i'm still getting a good signal from Anthorn, UK.

[coppercone2]

Can you get those signals very far away, if you just want to look at em without actually using it for positioning? Like in the USA. Or are they attenuated under the noise floor?

[hamster_nz]

I wonder if the army has a silo of GPS satellites ready to launch in case of war given the fact that they destroyed their loran system, a bunch of dormant GPS satellite loaded missiles might be cheaper to own as a redundancy then to maintain infrastructure that offers crappy accuracy.

I thought about this the other day. if you were wanting to intercept and/or disable a satellite, the GPS ones would be a good choice. You know exactly where they are and where they will be, and they can't really make defensive orbital corrections and still be in active service.

[chris_leyson]

WWVB will cover most of the USA but only guaranteed coverage at dawn or dusk it's not 24/7. MSF and DCF77 will probably cover most of Europe 24/7 because it's geographically a lot smaller. WWVB, MSF and DCF77 are used as secondary time and frequency standards and are no good for hybperbolic navigation.  Allegedly the UK is now looking at e-loran again because it's really easy to screwup GPS and we may or may not have access to Galileo. South Korea are upgrading their e-loran navgation because of suspected GPS jammning by DPRK. It would seem that the US and Western Europe have given up on secondary navigation if GPS were to fail. It all comes down to defence budgets I guess, but is it wise to put all off your eggs into one basket, some nations are taking a different view.

[EEVblog]

The receivers are a dime a dozen on ebay.
I've always wondered if they are of any use for something else?

[rigrunner]

Can you get those signals very far away, if you just want to look at em without actually using it for positioning? Like in the USA. Or are they attenuated under the noise floor?

It's going to behave the same as LW radio broadcasts, so reception at a couple of hundred miles during daylight and 800-1000 miles at night?

[LapTop006]

I see LORAN receivers every now and then.

Some of the better LORAN recievers may be good for oscillator salvage, but all the ones I've seen have been priced too high.

[CJay]

I wonder if the army has a silo of GPS satellites ready to launch in case of war given the fact that they destroyed their loran system, a bunch of dormant GPS satellite loaded missiles might be cheaper to own as a redundancy then to maintain infrastructure that offers crappy accuracy.

Not the best idea. The wake would possibly be interpreted as ICBM, and welcome nuclear WW3. Just imagine the tension when NK launched their missiles. If that happens during an active war between super powers, goodbye humanity.
[/quote]

I'm thinking if someone's knocked out GPS we're probably already in WW3...

[duak]

I wonder how hardened the GPS type satellites are to solar flares.  There have been big ones such as the 1859 Carrington event and one in 2012 that "missed us by that much".  Wasn't Fukushima Daiichi designed for a maximum Tsunami of 7 meters but encountered one over 9 meters?

I remember looking at a Litton laser gyro INS (inertial Navigation System) in the early 80s that was a bit bigger than a big desktop PC.  I'm sure larger aircraft still have backup INS so how big and expensive would a modern backup INS be for smaller aircraft or for smaller ships or fishing boats?  It wouldn't have the stability for long term navigation but good enough to get to safety.  No fun to be lost in the middle of a storm.

Cheers,

[CatalinaWOW]

For small boats and fishermen the backup systems are compasses, the stars, currents and charts.  No one has any business being out of sight (including fog) of the shore without these tools.  The further out you go the better you should be.

I totally agree that if someone is shooting down GPS satellites single launches, or even multiple launches of orbiting vehicles will be among the least of the world's worries.

Think about it.  Someone launched a large fraction of 24 satellite interceptors without worrying that it would start a nuclear exchange.

[texaspyro]

I wonder how hardened the GPS type satellites are to solar flares.

Very!   They are critical military infrastructure and are reported to be hardened against space based nuke explosions (I read that the shielding is made of tantalum).   They are also rumored to have some evasive maneuvering capabilities against ASAT weaponry (but a bucket 'o ball bearings dumped in their orbital planes might be a bit of a problem).

Nuke explosions in space are very inefficient at doing physical damage... nothing to propagate the blast wave.  If you didn't take a direct hit and can survive the EMP / x-rays you should be OK.

[Towger]

I only saw this a few hours ago.   There is a new series of GPS satellites with the first getting ready soon.  Says they have 8 times better resistance to jamming, but gives no details.  I can only assume military receivers have a frequently hopping mode and not limited to the 1.5ghz band.

http://gpsworld.com/first-gps-iii-satellite-shipped-to-cape-canaveral-for-launch/amp/

[Kleinstein]

It may not need that much to bring down the GPS system: It could be a software based attack - so worst case even a small country (e.g. north Korea, Cuba, Venezuela maybe even Grenada)  could in theory bring the satellites under there control. So they would be still up, but no use to the normal receivers.

[coppercone2]

I wonder if the army has a silo of GPS satellites ready to launch in case of war given the fact that they destroyed their loran system, a bunch of dormant GPS satellite loaded missiles might be cheaper to own as a redundancy then to maintain infrastructure that offers crappy accuracy.

Not the best idea. The wake would possibly be interpreted as ICBM, and welcome nuclear WW3. Just imagine the tension when NK launched their missiles. If that happens during an active war between super powers, goodbye humanity.

I'm thinking if someone's knocked out GPS we're probably already in WW3...
[/quote]

you can always get the kremlin on the line

Even if you don't agree with them, you can get things like SHAPE, Kremlin, Chinese govt on the line.

LOL OR hide GPS satellites in other satillties.

[coppercone2]

Even if you don't agree with them, you can get things like SHAPE, Kremlin, Chinese govt on the line.

Put your feet in Putin's shoes, would you trust the White House if you detect a missile from a known US silo coming to orbit?

If you say how many and where why not?He knows how important it is.