Nonsense or a sensible precaution?
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Nonsense or a sensible precaution?
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Actually, USN has never stopped training its navigators in celestial navigation. That's always been the back up to Satnav and GPS. The only thing new is that they're bringing back celestial nav to the Naval Academy curriculum for the first time since the mid 2000s.
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Celestial navigation
I think there are also a few satellites hanging around up there with decent star tracking.
Have been for many years I think.
(yes I know it's easier up there, or is it?)
Have been for many years I think.
(yes I know it's easier up there, or is it?)
wonder if it will also see a return of the obligatory boot polish on the astro-sextant eyepiece? Kept many a kipper fleet crew sniggering through those long tedious transits..
"Mildly" Eccentric Stardriver
Probably apocryphal, but the story goes of ATC asking a USAF aircraft what nav system he was using.
"We're using Charlie"
"Understand you're using Loran Charlie?"
"Negative. We've got a little fat navigator called Charlie, and he's shooting astro"
"We're using Charlie"
"Understand you're using Loran Charlie?"
"Negative. We've got a little fat navigator called Charlie, and he's shooting astro"
When we took a Jaguar across the pond en route to Nellis, the four navs on the two tankers were happy to take INS updates from the pilot in the Jaguar, which got us to Goose with around a 1nm error - somewhat better than we could have achieved with astro which was all we had away from land.
On the other hand if somebody had been able to shoot astro on board Korean Airlines 007 on September 1st 1983, perhaps 269 people might have reached their destination instead of ending up in the sea off Sakhalin.
On the other hand if somebody had been able to shoot astro on board Korean Airlines 007 on September 1st 1983, perhaps 269 people might have reached their destination instead of ending up in the sea off Sakhalin.
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Shirley if is ship based, an automatic autonomous tracking system could be used such as that on the SR71.
Here's a discussion on the subject right here from a few years ago:
http://www.pprune.org/tech-log/10416...avigation.html
Last edited by KenV; 15th Oct 2015 at 15:36. Reason: added link
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I have my sight reduction tables somewhere, and in a small yacht with a fickle electrical system and no engineers/electricians, I'd also bring a sextant, if only to help pass the time, but if I was the skipper of a major navy ship, I'd expect reasonably good dead reckoning, inertial navigation, clues from sonar, maybe even water temperature, as well as radar pilotage in coastal areas, would be quite enough to find my way around...
interestingly among others, shipborne radar, the internet, land line telephones, mobile telephones use GPS time signals. No GPS is a potential major crisis.
https://www.newscientist.com/article...jam-your-life/
http://rntfnd.org/wp-content/uploads...Paper-2008.pdf
https://www.newscientist.com/article...jam-your-life/
http://rntfnd.org/wp-content/uploads...Paper-2008.pdf
In 1996 it was discovered the original GPS spec was seriously wrong. Bit Timing Errors could cause significant errors during a single flight. If memory serves, anything GEM 1, 2 or 3 was affected. Compromised HaveQuick II, compounded by the US de-modifying thousands of radios just to make sure they wouldn't work. By 2003 the MoD corrected the former in one aircraft, the latter in two. (One had both problems. Now 19 years since its RLG/INS with embedded GPS was bought). An own goal that might be more of a problem than hackers. Maybe the penny's just dropped.
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the internet, land line telephones, mobile telephones
There's quite a few land-based atomic clocks that provide a public time signal, and most devices can easily be set to use specific time sources (eg no gps)
There's quite a few land-based atomic clocks that provide a public time signal, and most devices can easily be set to use specific time sources (eg no gps)
True, but not everyone is prepared nor will any changeover be swift and painless. Nor will corresponding units necessarily be on the same source.
Just saying it would not be smooth.
Just saying it would not be smooth.
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In my minuscule navigational experience, I was pointing HMS Brierley in the right direction somewhere off the Isle of Wight [or somewhere nearby] using radar and cross-checking that with a Decca plot [YAY, Decometers!]. I was summoned to the bridge and told to start using visual bearings from assorted lighthouses, headlands and other such landmarks.
The answer was the same, but it was cold and wet up there on the bridge
The answer was the same, but it was cold and wet up there on the bridge