Imagine a fiber optic cable that can sense it's about to be dug up and send a warning Imagine an optic fiber that can sense the presence of a nearby jackhammer and warn its owner that it is in danger of being dug up, just in time to tell diggers not to sink another shaft. Next, imagine that an entire city's installed base of fiber could be turned into sensors that will make planners think twice before installing …
> Is this London the one in a parallel universe?
Could it be a backwards universe ?
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RIMMER: (Reading the marker) "Nodnol? 871 selim?" Nodnol? Where's Nodnol?
KRYTEN: It's London, 178 miles. It's backwards.
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CAT: What's this?
LISTER: Nodnol? Hang on, wait a minute! Nodnol! Nod. Nol. It's in Bulgaria, isn't it!
CAT: Are you sure?
LISTER: Geography was my number one subject at school. Nodnol, Bulgaria -- rich in animal produce and mineral wealth, just south of Bosnia.
CAT: What's the selim?
LISTER: Well, that's obviously Bulgarian for kilometers, isn't it?
CAT: (Sincerely) You're so smart, I'm glad I came with you!
LISTER: Well, we are the smart party!
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That's along the lines I was thinking. Lots of three letter agencies would probably* love a passive fiber optic microphone. That would be a pretty undetectable bug.
*qualified because it's also possible the tech already is in use by some of the spookier agencies.
Perth WA is inland. Did you mean the coastal port of Fremantle and the ship dragging anchor in Gage Roads ? Gage Roads is the approach and anchorage area NW of Fremantle where ships hang around, waiting, waiting as Oz insane lockup drags on on, like an anchor...
As for technology of using cables as sensors, another reason to tread softly, and drive a JCB
Perhaps Perth is being referred as in the greater metropolis of Perth, of which Fremantle comprises one of 11 cities in the greater region. Much like New York City comprises its five borough cities (Bronx, Manhattan, Kings/Brooklyn, Queens, and Staten Island) and Manila when referred as a metropolis comprises numerous sub-cities such as Quezon, Caloocan, Las Pinas, etc. as well as the actual city of Manila.
Many years ago ('02 or '03)I was asked by the CEO of Telstra, if I could provide them with a backhoe detector.
It was already well known that the same fibre that carried the comms could also be used as a sensing element.
The company I worked for already had the tech to do the sensing.
We declined.
You certainly can sense when the digger is about to rip your cable to shreds,
But when that digger and cable are kilometers, if not tens or hundreds of kilometers away from your sensing point, well... whats the point, you'll never alert them in time to stop them.
Yes ti can be done, and has been done already for a long time in specific cases where the distance to be sensed is very small and the response is guaranteed to the rapid. But for normal teclo networks.. dream on.
The BOFH solution would be to co-locate segments of detonating cord along your fiber path. Combined with some electronic safe/arm devices, slappers, and an occasional booster + main charge to keep things exciting you can defend your cable.
"If I can't have a cable, you can't have that 'effen backhoe blade!!"
Bonus - after a few shots it's unlikely you will have idiots trying to tap the cable, too.
Sorry to burst your bubble , but it doesn't work.
The backhoe(JCB) drivers are told "dig trench here" and dig it they will...... they cant be reasoned with, they dont feel pity or remorse or regret and they absolutely will not stop until your cable has been severed.
Having worked with major and minor Telco's around the world, getting someone on site to be able to pinpoint any break location with an OTDR in less than an hour is generally viewed as 'best case'. Even places like Singapore and Hong Kong, quite small geographically but with very extensive fibre networks, know from experience that the OTDR, the tech who knows how to use the OTDR, and the nearest fibre cabinet to the break, are all in different locations.
Yes ti can be done, and has been done already for a long time in specific cases where the distance to be sensed is very small and the response is guaranteed to the rapid.
For anyone unaware, fibre optic has been wound around nuclear weapons in storage facilities for some decades (the tech was developed/refined in part for nuclear security applications). Of course they don’t care so much about measuring specific magnitudes - just passing a threshold. So much as bump the weapons rack and the vibrations will trigger a… robust response from the guardhouse.
Means if you get into the bunker undetected in the first place it’s almost impossible to so much as touch the weapons without tripping an alarm.
Particularly important in places like Germany where weapons might be hosted on a foreign base with a relatively small guard detail. The fibre trip can alert the local US base that someone is in the bunker and the troops might have been overcome so they can dispatch a larger force to assist/see what’s going on.
Conceivably you could "upgrade" the digger so that it automatically shuts off when a signal is sent that it is about to dig into a cable.
Whether the cost savings from not digging into cables can offset the costs from multiple unnecessary stoppages remains to be seen of course.
Perhaps the stopper can come from digger-producers as part of the subscription you pay for your digger-use-license....
My post above (the one removed by a moderator because it contained an article correction - I should have separated comments) contained the following question:
Can it detect the activity with enough warning to get someone out there? Or to navigate the local bureaucracy to find out who's digging to give them a call?
I suppose you've more or less given me my answer.
This post has been deleted by its author
The Construction industry is increasingly using fibre optics for monitoring purposes.
Cambridge University has a smart infrastructure group
http://www.eng.cam.ac.uk/news/applications-distributed-fibre-optic-sensing-monitoring-civil-infrastructure
They used fibre optics for monitoring some of the Crossrail shafts constructed >10 years ago (I know a lady that got her PhD out of that work).
The Construction Industry Research and Information Association (CIRIA) is running a fibre-optic related webinar (Application of fibre optic sensors in site investigation) in about three weeks' time, if anyone is especially interested in the topic:
https://www.ciria.org/CIRIA/Navigation/Events/Event_Display.aspx?EventKey=E21713&WebsiteKey=3f18c87a-d62b-4eca-8ef4-9b09309c1c91
(Declaration of interest - I don't work for CIRIA, but did have a hand in getting this event happening)
One, very obvious drawback. Retrofitting onto existing routes is largely impractical because of monster streetworks requirement. If you already have a fibre (as we do) there are of course options.
We've evaluated a bunch of optically based sensing systems, vibration, thermal, pressure and they aren't the panacea. Sensing a problem doesn't stop it. Lead time on warnings is not enough for the corrective action to be any different. So at the moment, sensors are extra expense for no real change in performance.
When you've worked out how to do preemptive intervention come back to us with your answers.
A/C for obvious.
Fibre optic cables are generally not armoured. They are basically very long glass rods inside rubbery plastic sleeves. There is probably something else between the glass and the outer sleeve to help avoid stress on the glass bit when flexed. You run them through conduit.
When run over a really long distance then you would obviously run them through a SWA type cable. That is generally a submarine cable.
My office (UK) has several private telegraph poles - three of them. It's simply an oddity of being a bit odd - the building that is! It used to be a NHS clinic and for ... reasons ... each desk had its own BT exchange line. They didn't seem to have an exchange (PBX) nor use the one in the hospital that is about 200m away. There is a 150 pair line running to the building. It took two days to strip out the redundant wiring inside and out when we bought the place. We have a IP PBX.
We bought a couple of leased lines and a pole was erected by OpenReach to carry them, instead of using the existing wood work. The fibres look like a four or eight pair of which two are in use. They are quite thin, rn through some trees and have survived some pretty windy weather so far, so all good.
You would think. However, I've seen bits of hacksaw lodged into the side of a 275kV cable; with fingers very definitely still attached to the hacksaw... but not the arm and the rest of the human. There's a thief somewhere that was "bloody lucky" to get away missing their fingers let alone an awful lot more.
The worst of it is the old power station where I saw this, it's not the first time that someone thought that this was a good idea to steal some easy copper off the network. At least two fatalities recorded from such theft attempts in last 20 years.
I could point at a particular group being responsible for these repeated theft attempts, but for whatever reason there is not a name anymore for them that is politically correct. So I shall be done with it and simply refer to them as scrotes.
Traffic monitoring using buried fibre optic sensors is well established technology. This is just another variant on "deform a cable and detect the deflection using OTDR".
The biggest advantage of technology has to be in sub-sea fibre-optics where access is difficult with long distances between repeaters.
Detecting earthquakes and anchor damage seem like a euphemism for detected physical hacking for espionage. Israel demonstrated that fibre-optic can be hacked; provided you don't splice all fibres at the same time, it's undetected by the owner of the cable.
Getting an early warning that somebody is interfering with a sub-sea cable is only really useful if you can have a hunter killer submarine lurking underwater to kill an attacker before they get away - for that you'd need nuclear powered submarines.
While Australia is a relative backwater (in global telecoms), it is significant that none of its sub-sea cables go near China.. where anchor damage and earthquakes are such a problem.
This used to require a single unused fiber. I expect that these days they can build the detection logic into the signal processors
The engineer used to have a radio playing in his office with the output signal transmitted by laser through a live fishtank with an active aerator.
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