How accurate is GPS in detecting the position of your car?
Take that, plus some advanced military technology and you got your answer.

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Then stop coloring and visit Meat187's mix archive!

+- a few yards. Probably better than that.

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quote:

Originally posted by Meat187 How accurate is GPS in detecting the position of your car? Take that, plus some advanced military technology and you got your answer.

Winning response, pretty much.

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CEP on Trident D5 is about ~100m at max range (11,300Km).

That means that 50% of its warheads will fall within ~100m of its target.

Considering that the ones with the W88 warheads have a yield of 475Kt thats pretty much over kill.

Trident actually doesn't use GPS. It uses INS+Star Sighting (the guidance system has a camera that basically knows what the stars should look like at points in its trajectory, and it then adjusts the flight path till it matches the stars, sort of like TERCOM in the Tomahawk).

There has been tests with GPS systems, but they are not deployed. INS+Star Sighting is usually a more reliable choice because GPS can be jammed, destroyed, etc.

What really is the kicker is that these missiles are launched from Submarines, moving platforms, and can hit that accurately.

Actually another interesting thing is that most people think JDAM (the guidance kits attached to older iron "dumb" bombs) is GPS guided.

It is actually INS (inertial) guided with GPS updates to increase accuracy.

JDAM can be dropped and hit roughly with the same accuracy with or without GPS.

Oh, didn't see you asked about land too. Minuteman III is pretty much as accurate as the Trident D5.

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Originally posted by Joss Weatherby (the guidance system has a camera that basically knows what the stars should look like at points in its trajectory, and it then adjusts the flight path till it matches the stars

Seriously?

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Originally posted by Sushipunk Seriously?

Yes.

http://www.evaluationengineering.co...tem-part-1.html

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Although the preceding capability provides considerable navigation accuracy, additional accuracy is achieved through a stellar sighting performed midway through flight. Using a charge coupled device (CCD) mounted on the stable member, the system sights a star and performs a navigation update to remove any uncertainty in the system’s initial conditions and thereby further increasing the accuracy of the overall system.

As Nou said, there are a lot of different systems:

http://en.wikipedia.org/wiki/Missile_guidance

You can be extremely accurate, but when throwing a nuke robustness is obviously more important than hitting within a few meters of your target.

GPS is obviously not used from submarines because there's no signal down there.

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Then stop coloring and visit Meat187's mix archive!

Nuclear weapons do not have to be accurate...

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quote:

Originally posted by chinamon chinamon is INCH MOAN. LOL so fitting.

Actually just realized what I think the term "spinning up" means when they go through the launch procedures in a submarines. I assume this period is the subs INS navigation system initializing and "spinning up" the gyros in the guidance systems on the missiles. This, I assume, is pretty much the same as initializing the INS system on aircraft, and takes a few minutes.

INS is pretty awesome, its amazing how accurate these systems can be with absolutely no outside help.