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Old 02-24-2016, 07:23 AM   #1
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Back to basics for Navy navigators

Interesting quote from news article:

"It was how Odysseus sailed the seas, how Columbus reached the Americas, and how Lawrence of Arabia found his way across the vast, featureless deserts of the Middle East.

For millennia, travellers used the stars to guide them on their journeys – a technique which, in recent decades, has been replaced by modern technology.

But now the US navy is reinstating classes on celestial navigation for all new recruits, teaching the use of sextants – instruments made of mirrors used to calculate angles and plot directions – because of rising concerns that computers used to chart courses could be hacked or malfunction.

“We went away from celestial navigation because computers are great,” said Lt. Cmdr. Ryan Rogers, the deputy chairman of the naval academy's Department of Seamanship and Navigation. He told Maryland newspaper The Capital Gazette: "The problem is there's no backup."

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Old 02-24-2016, 08:08 AM   #2
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Al Johnson
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Old 02-24-2016, 10:02 AM   #3
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No mariner shall rely on one single source of navigation. No matter how many computers you have, you are relying on one set of satellites.

Someone on board who can shoot a star is not a bad idea.

And, remember the bad guys use those satellites too. Having the option to turn them off and not getting lost may be a good idea.
Experience is a cruel teacher.... first it gives the test. Then it gives the lesson.
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Old 02-24-2016, 10:26 AM   #4
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Our advantage is precise tactical warfare. Knowing where everyone is down to the meter...good and bad...keeps us at the advantage.

Not saying we couldn't lose the GPS constellation...but there's a whole shi*load of people making sure that doesn't happen. Backups are good...but I doubt we would every turn them off intentionally as selective availability was tossed a long time ago.

Economically they are probably just as important as to our warfare capabilities.

I do think with all the warnings of GPS outages/testing in fairly small areas...that jamming capability at a local scale is being done.
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Old 02-24-2016, 12:53 PM   #5
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I think the Navy got a wake up from those Russian planes flying by, using ECM gear of some type that disabled their comm/nav gear.
There have been at least two such incidents in the last several months.
The last one was those two small craft that got captured by the Iranians, the first was some larger cruiser a while back. It left the site of the incident in a hurry.
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Old 02-24-2016, 02:04 PM   #6
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JW-"What goes around comes around". My Dad was USNA Grad, '42, and even though he went into the USMC, he taught Seamanship and Navigation at the Academy in the mid-50's (as well as Gunnery as he was an artillery officer). I learned the basics of celestial navigation back then when I was around 8-10 years old. Of course, I had no idea what I was learning! Glad to see it coming back for the Navy.
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Old 02-24-2016, 03:16 PM   #7
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Originally Posted by psneeld View Post
I do think with all the warnings of GPS outages/testing in fairly small areas...that jamming capability at a local scale is being done.
I know there are GPS / Cellular / wifi jammers made and sold into the U.S.

Happen to have had one once... No cell service for the movie theater with one of those on... Also worked well for meetings since no one could cruise the internet during the meeting, as well as no text messages, or emails to interrupt.

Some truckers who don't want the boss knowing where they are use a GPS jammer to jam the reporting device. Of course that looks very suspicious.

Anything on their frequency will take GPS off the air, since GPS operates at about -140 to -150 db signal strength. Of course, anyone emitting a frequency on a battle field becomes a target for a HARM...
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Old 02-24-2016, 08:12 PM   #8
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Many years ago, I joined my brother-in-law on a "family cruise" in aboard a submarine. My memory is that they plotted a paper course using an inertial system, used an early GPS (or Loran, I can't remember which), and used a sextant when possible. I was impressed with the redundancy and double-checking that went on.

Of course, I also realized that keeping sailors busy on a long cruise is what keeps them sane. They had plenty of downtime to plot a course regardless of the necessity of doing so.

I use survey-grade gps in my grading business, but I'll never throw away the fiberglass measuring tapes, or the stringlines, or the builders levels.
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Old 02-25-2016, 07:13 AM   #9
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"I do think with all the warnings of GPS outages/testing in fairly small areas...that jamming capability at a local scale is being done."

A single small nuke launched 5 miles to 200 miles up will take care of much of US communications and navigation satelites.

Any tramp steamer will work as a launch platform.

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