Seeing stars again: Naval Academy reinstates celestial navigation

Re:Seeing stars again: Naval Academy reinstates celestial na... by xg15 on Wednesday October 14, 2015 @06:07AM (#10385810)

I wonder if, with the use of image analysis, it would be possible to create a "robo-sextant" - i.e. a system which scans the sky in certain intervals, locates the waterline, sun or other celestial bodies and performs the necessary calculations. Such a system could be used to e.g. detect GPS manipulation quickly

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Re:Seeing stars again: Naval Academy reinstates celestial na... by mninm on Wednesday October 14, 2015 @06:53AM (#10385919)

Trident missiles (a type of ICBM currently being carried aboard US submarines) do just that.

Once launched a Trident, using a camera, gets a fix on a single specific star. It then uses the data on that star's position to correct for any errors in its internal guidance system.

See: https://en.wikipedia.org/wiki/Trident_(missile)

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Re:Seeing stars again: Naval Academy reinstates celestial na... by ju-st on Wednesday October 14, 2015 @09:02AM (#10386337)

There are also star trackers in use by spacecrafts.

https://en.wikipedia.org/wiki/Star_tracker

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Re:Seeing stars again: Naval Academy reinstates celestial na... by xg15 on Friday October 16, 2015 @10:47AM (#10399646)

Wow, I wouldn't have thought that. Thanks much for the information.

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Re:Seeing stars again: Naval Academy reinstates celestial na... by dagw on Wednesday October 14, 2015 @06:17AM (#10385831)

It's an idea that has been around for awhile: http://www.ri.cmu.edu/pub_files/pub2/cozman_fabio_1995_1/coz... is just one of dozens of papers covering the idea.

There even appears to be a patent on the idea: https://www.google.com/patents/US7706917

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Re:Seeing stars again: Naval Academy reinstates celestial na... by Ao7bei3s on Wednesday October 14, 2015 @06:44AM (#10385899)

It has actually been done: the SR-71 Blackbird had one.

https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird#Astro...

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Re:Seeing stars again: Naval Academy reinstates celestial na... by mikeash on Wednesday October 14, 2015 @09:50AM (#10386571)

Amazingly, it worked during the day (on the ground) too!

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Re:Seeing stars again: Naval Academy reinstates celestial na... by mxfh on Wednesday October 14, 2015 @07:27AM (#10386000)

The patent mentioned only covers projecting a light pattern to the ceiling of a room for indoor-navigation of household robots.

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Re:Seeing stars again: Naval Academy reinstates celestial na... by dagw on Wednesday October 14, 2015 @07:32AM (#10386007)

My mistake. I guess I should know better than to only read the title of a patent.

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Re:Seeing stars again: Naval Academy reinstates celestial na... by cgriswald on Wednesday October 14, 2015 @11:43AM (#10387248)

Such a system does not solve the problem.

First, the system would be vulnerable to many of the same problems: hacking, sabotage, and electrical failure. Second, it would likely not be as robust under less than ideal conditions in which human beings with a sextant would still be able to function (e.g., partially cloudy conditions).

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