Yay for pagers

Back in the early noughties, we watched in horrified fascination how some fellow students apparently had lost the ability to do anything at all without first calling a mate or two to discuss how to do it. Now kids would presumably tweet or post on facebook or text a question or two. It's quite amazing how quickly people start to believe they won't survive without certain high technology they've become accustomed to.

Having a jolly old excercise trying to do exactly that, surviving without, say, GPS, or phone, or what-have-you, is instructive. Plenty of people should try, just to see where the weak spots in their thinking are. Knowing you're vulnerable and understanding the consequences is half the battle. This fisherman might have a point he's missed the announcement, but I would've thought he'd've picked it up from some marine data service or other. I mean, if you have GPS, why not that? IIRC there is at least one but not being a mariner I can't quite recall what it was called.

As to pagers, such systems have a much wider range than cellular phone systems do, and personally I'd like control messages to be sent over such a system, obviating the need for mobes to always stay signed in to the nearest tower, which is inexplicably recorded and kept for years. The phone can sign in when it gets a page telling it a call is incoming. And SMSes don't even need a sign-in, the page would suffice. I think that's a good idea, yes.

I like your thinking in relation to control messages but in practice this would not work. Suppose your mobile is switched off/out of coverage for example, and an SMS was sent out via the pager system, then the recipient would never receive it.

GSM off, SMS vanishes?

SMSes already fail to get delivered if the phone remains switched off during the SMS its entire lifetime. Though I don't know what'll happen if the phone company decides to store "sent" messages for longer than that anyway. Probably not deliver but archive anyway. Anyhow. Pagers of course did have that problem but with lower power draw and simply repeating sending it once an hour or so for a day or two that was "good enough". With GSMs, well, maybe they can have a pager-like modus, just receiving pages without signing in to towers. And perhaps they could delay acknowledgement of received SMSes until next time they really have to sign in. Or(/and) just sign in once a day or so for a full status check. I don't see it as a big problem since paging systems typically have better reach anyway. The only thing that changes is that the network doesn't get instant gratification, er, acknowledgement, and since the messages are tiny compared what we know how to pump through the aether now-a-days, well, not really a problem.

It's not that bad

If he had named the Bahamas India instead of Bahamas nobody would have been any the wiser.

And the reason they said they would never switch off GPS globally, and why they removed SA, was because they wanted to remove as many justifications for Galileo as possible.

It would have been nice if that was included in the office notice.

The notice at www.scotland.gov.uk/Resource/Doc/295194/0120735.doc doesn't mention communications - just blocking GPS.

The Ofcom notice you mention does include these other frequencies but how many people are going to have signed up to this?

If I had to guess, I'd say that the jamming is of "moderate-to-high" level importance. It is absolutely critical that the military practice with degraded electronic communications, especially those they tend to take for granted such as GPS. It's possible as a one-off to just "make believe" that they don't have any GPS, but that seriously reduces the sense of reality, as well as eliminating any ability to practice countermeasures.

That said, the RN is NOT insensitive to safety issues. If it was just fisherman losing their nets, I suspect that they would respond the same way that the US Air Force did when they were practicing with some black tech that kept opening (and according to a few complaints, frying out) garage door openers across entire suburbs. Specifically, they basically said: "We're the military, cope with it." I suspect that the RN would have responded the same.

On the other hand, safety issues (at least among their own civilians) tend to get a response from most Western militaries. Some Admirals are probably gritting their teeth at the "dumb fisherman," but they'll plan ahead for next time.

-d

Not so

Military jamming generally jams as much or as little of the frequency band as it needs to, after all the more you're jamming the easier it is to locate the jammer, which is generally bad news for them. The latter is why the RN don't have a lot of active jamming equipment and most of that is used against operational units to train them to fight though.

The RN have been conducting Joint Warrior or whatever it's called these days for decades, they've been jamming GPS for at least the last ten years of that without the world ending. Considering the timing of the exercise is the same every year it strikes me that the original complainer is either very very stupid, or trying to pull a fast one.

they don't actually 'jam' the signal by generating competing large RF transmissions. They degrade the signal by playing around with the information that your GPS decodes to work out where it is.

Mil grade GPS have extra functionality where they can receive corrections for the 'jamming' in real time.

ALL civilian GPS are only as accurate as the military feel like letting them be - read the small print of the free to use at own risk license no one can ever be arsed to read.

Obviously you are unaware of the change in use of the term 'jamming'

WAFIs etc

@Spider

As one of the WAFIs, I sympathize with your rant.

But I would point out that I have often encountered commercial vessels on autopilot with no lookouts.

@carabus Skipper dead?? #

Single point of failure?

No, I don't think that's a valid or vaguely true arguement. But hang on, I'll ask the first mate...

That wouldn't take into account the fact that a lot of GPS receivers are integrated into the systems they're part of, i.e. you can't just switch off the GPS part, so to practice with a degraded GPS input you need a degraded GPS signal. Similarly if you disconnect the aerial you don't get a degraded signal, you just don't get a signal which makes for an unrealistic training scenario.

@ EPIRBs need GPS

"I yacht, I sea kayak and I hill walk. In an emergency, I'm likely to be unable to get through on marine VHF (hand-held at sea level or below) or mobile phone. I don't rate my chances of anybody seeing a flare in/off NW Scotland. So my only way of raising the alarm is by triggering my EPIRB. If it doesn't have a GPS fix, I'm unlikely to get much of a response."

So don't go out when the military has announced, LONG in advance, that GPS will be down during X block of time over Y area.

Is this really such a hard concept to comprehend?

-d

P.S. If the RN is nearby, and you're at sea, I'll bet you dollars to doughnuts that they will not only receive your VHF transmission, but can triangulate on it. You do have VHF on your yacht at least, don't you?

GPS !=Tom Tom

The myriad of systems onboard a warship or aircraft using GPS are not presented by a stand alone box you can lock in a safe, well some of them are but most are integrated systems such as the electronic chart system or the central tactical system which continue to work with a degraded/no GPS signal. In those situations it's necessary for the operator to manually update the position using whatever method they judge appropriate, crucially though most of them don't have a GPS on/off switch it's an all or nothing choice. Obviously it's a bit unrealistic training for war with half your ship turned off just to simulate GPS not working, that normally happens later when you train for what to do after your ship gets hit.

And they're not afraid matelots will cheat, they know they will, that's how you win wars.