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Comment by pyrocat | Hacker News Reader

Countdown to https://www.youtube.com/watch?v=7jVsQToSfag

I imagined the final scene from Wanted (2008)

https://www.youtube.com/watch?v=QADr4hVKs3Y

Bah, 1984 called and Tom Selleck and Gene Simmons want their self-guided bullets back: https://www.youtube.com/watch?v=lA6ybohAVq8

This is being voted down, why? The entire subject of _Runaway_ is self guiding bullets and killer drones, and it came out in 1984.

This is exactly what popped in my head when I read this headline. The camera angle from the bullet is pretty hilarious, with people diving out of the way and what not.

ROFL

/thread

Seriously though. How do they plan to designate the target for this round?

I believe that targets are marked using a laser.

If you can aim the laser, you can aim the weapon. This would certainly involve computer vision, makes it even more scary.

I think the idea is to automatically compensate for wind or other factors that would otherwise take the bullet on a path that is not on target. I think the part where they aim away from the target is just for demonstration.

You can hit stuff that moves after the bullet is fired. It doesn't require computer vision.

A laser is unaffected by things like gravity, recoil, wind, dust particles, drag, etc... Also, if it's a line of site issue. The sniper could be out of the line of site and as long as the laser operator can put light on target, it still gets hit (theoretically).

A laser is affected by temperature differences in the air (think about the mirage seen over a hot road surface) and even by gravity; a laser beam drops over distance like a bullet or a baseball, only it travels so fast that the effect is unnoticeable over earth-scale distances.

The effect of a temperature inversion, though, can be significant; it's possible that military laser designators use diverse wavelengths to avoid or compensate for it.

Yes, yes, your technically correct (the best kind of correct?) but compared to a bullet arching through the air, it's minimal.

After thinking about it more, I realised you're absolutely right. It doesn't matter if the laser designator beam takes a knuckleball path through the intervening air; if the laser dot is on target---classical optics are time-reversible---the shooter will see it on target. The effect of those same air density variations on the bullet is similarly irrelevant [1], because the bullet continually aims for the laser dot.

It works by negative feedback, like a servo; all the error terms in the middle cancel out. Neat!

[1] The refraction of a laser by air density variations is bound to be different from the ballistic effects of those same density variations on a bullet passing through them. But it doesn't matter, because the corrections are applied continually along the trajectory, not at the source.

Some(body|thing) else can aim the laser and now you can hit out of sight targets.

I thought they were marked by the incumbent powers that be!

Anyone seen Aliens? Anyone say M56 Smart Gun?

http://alienanthology.wikia.com/wiki/M56_Smart_Gun#Target_Tr...

"When powered up, the gun begins tracking targets via its infrared tracker mounted above the barrel. The tracker consists of a 256 x 256 element platinum-silicide focal plane array cooled to 770 degrees K by a tiny cryogenic gas cooler working on the Stirling principle. This system monitors a 30 degree cone in front of the gun and transmits high-resolution thermal images in the 8-10 um range to a miniature video display in the operator's eyepiece."

Thats all available technology - right now.

The replay button of The Fifth Element trumps that, but it's not available yet http://www.youtube.com/watch?v=U7wOX2WqbXE

That... was the parent comment.

Maybe I misunderstood your comment but parent was about Aliens, this is about The Fifth Element. Different movies different fictional weapons. TFE's one is more fictional.

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