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Corrected Laser Sight

Use invisible laser range finder to correct laser sight
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(+3, -1)
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Laser sights have been fitted to weapons for ages, but due to the fact they don't show up on the weapons of the more dedicated professional killers, I'm guessing they're not perfect.

Now, lasers fire a perfectly straight beam of light (with reference to the local space-time curvature, naturally). Bullets however, tend to fly in a parabola. This means that the path of a bullet and the path of a laser are inherently mismatched. Optical sights have had mechanisms for correcting for range-dependent bullet deviation for ages. It's about time laser sights grew up a little.

So, fit your gun with the new bs0-laser sight for increased reliakillity. This will consist of an IR laser rangefinder, which will constantly be scanning the environment in front of the gun. Programmed with the characteristics of the gun and ammunition, a microcontroller will adjust the angle of the VISIBLE laser according to range. This will require very small adjustments and will need to be mechanically robust, so I was thinking of an electrically modulated piezo system - fast, robust, small accurate movements. You could also use a teeny-tiny jackscrew, but that's not as cool, and sand would get in it.

For night operations you might want 2 IR lasers rather than a bright visible one, you wouldn't want to be given away because a cat is chasing your aiming point.

bs0u0155, Mar 06 2013

Laser strike epidemic http://www.theregis...er_strike_epidemic/
Please don't lase that plane. [Loris, Mar 07 2013]

Burris Eliminator http://www.burrisop...com/laserscope.html
Basically fulfils the intent of this idea, but does so without projecting a beam onto the target, but rather displays a "point of impact" dot into the field of view of the scope itself. Not to say I really like these things, but I know people who have used one and it's a bit ridiculous. [Custardguts, Mar 07 2013]


       For shotguns, the same system could ditch the laser and go with a standard LED light source in a focused reflector, the size of the cloud o'lead could be adjusted by focusing the reflector, and possibly using RGB LEDs as a visual indicator of how much damage you'll do to what you hit.
bs0u0155, Mar 06 2013

       Many "dedicated professional killers," which is a slightly rude way to describe special forces soldiers, use IR laser sights which are invisible to the human eye, although these too have their limitations. They are visible through night- vision devices as well as passive collectors such as the optical sights designed to be used in concert with them (the scope on my 6.8mm AR-custom picks them out). The red laser sights are primarily used in defensive situations, when quick target acquisition is far more important than concealment. The new green lasers are used mostly by canny hunters.   

       Bullet drop over the range at which laser sights are useful is so slight as to be of negligible effect. I have yet to use a laser that is visible at more than 50 yards. Even with a high-powered scope, the parallax makes it impossible to pick the dot out of background clutter.
Alterother, Mar 06 2013

       Assuming you actually did want to implement this, why would you use two lasers? Just pulse the one laser (visible or not) and measure the delay. This also eliminates the possibility that the range finding laser is pointing at a different object than the targeting laser.
scad mientist, Mar 06 2013

       //Many "dedicated professional killers," which is a slightly rude way to describe special forces soldiers,//   

       Also hitmen and other organized crime enthusiasts, pro-hunters, the more robust elements of the law enforcement community....
bs0u0155, Mar 06 2013

       // I have yet to use a laser that is visible at more than 50 yards.//   

       Hmm, you'd have to be a pretty poor rifle shot to miss anything at 50 yards or less.
bs0u0155, Mar 06 2013

       Actually, I'm a pretty damn good rifle shot, which is my point: laser sights are most useful in fast-paced short range situations such as asset protection or structure clearing, making bullet drop a total non-issue.   

       Since I'm not a combat shooter, I don't own any. They're next to useless on a hunting or comp rifle (except when hunting coyotes at dusk, which is when the green lasers are pretty handy) and I practice reflex sighting with a handgun, but I have used them at exhibitions and rec shoots.
Alterother, Mar 06 2013

       If a laser sight is zeroed at 25' and the target is at 12', the shooter simply halves the gap between the muzzle and the sight aperture and adjusts his or her aim. Some operators align their laser sight with the barrel, so that the bullet placement will be the same distance from the laser dot no matter the range. Learning to aim 1" high with a laser but still aim true over the iron is no big deal for an experienced shooter, much easier than learning to dope range with a fixed optical sight.
Alterother, Mar 06 2013

       //Actually, I'm a pretty damn good rifle shot,//   

       Slight misunderstanding there.... I was trying to highlight the point that if the effective range of a laser is only 50 yards or so, then even an average shot would be OK with standard iron sights.   

       Out of interest, how are people blinding airline pilots with lasers at many hundreds of yards? These are clearly bright enough to see at this sort of range if they are dazzling/blinding.
bs0u0155, Mar 06 2013

       When I said "a laser visible at more than 50 yards," I meant a laser _sight_ with a visible return at over 50 yards. Having a laser shined right down your pupil from several hundred hards away (these are the latest generation of green and blue lasers, mind you) is very different than trying to pick out what little of that light is reflected directly back to you from a rough, random surface amongst all the stuff that most of the world is cluttered up with. If you shined a laser at mirror at long range and hit it at or near ninety degrees, yes, you'd see it reflected, but human skin, deer hair, brick, dirt, even the glossy paint on a car isn't nearly as cooperative.   

       Maybe somebody with an easier handle on the inverse square law can explain it better.
Alterother, Mar 06 2013

       //, how can you even SEE the pilot at any appreciable distance// Well, if we're being honest, there are some rediculously powerful handheld laser devices available, in the 1 watt range which would dazzle you pretty hard. It would be a trivial excercise to strap one to a telescopic sight on a tripod and... Well, it's been well covered in fiction and I'm sure it could easily be done. Whether it's actually being done is another story.   

       As to the idea, the fact of the matter is that a projected dot (ie one that is visible to the target, and any other casual observer) is of little utility other than when being used for shooting from the hip, or when using night vision, etc. If the target is somewhat distant, and your optic on your weapon is sighted in, why put a dot out there for all to see when your crosshairs make a perfectly good aim point?   

       For any medium ranges (say beyond 10 metres but less than say 300) - there is a plethora of CQB optics available in reflex and/or holographic configuration that are well proven to facillitate rapid target aquisition - once again with no projection of signature onto the target.   

       Lastly, the idea of point-of-impact correction is a good one, but sadly well baked. Look up the Burris Eliminator range of telescopic sights. They have an inbuilt rangefinder and calculate point-of-impact for ballisic fall, and place an aiming point onto the reticle of the scope. There are much less well advertised military variations on this theme that do the same thing.
Custardguts, Mar 06 2013

       //I so want to see that in a movie. Professional assassin on rooftop, gets a clear shot and is thwarted at the last second by a cat. "Sorry sir we had another cat."//   

       I, too, liked the consideration taken of the cat issue.   

       I was imagining that in a film it would be the cliche brutal assassin with a heart of gold. Who can then show his/her soft side by teasing their pet cat with his/her gun.
Or I suppose guard cats could be distracted.

       // I suppose it's possible, if you got 'em on an approach vector close to the ground, right before they land, //   

       Actually, this is precisely when it's a problem.
Night-time landing, cabin lights dimmed, pupils fully dilated, then some dick with a high-power laser flickers you in the eye just as you're doing the most critical part of the process. Lasers do have some spread, so from half a mile or so away the light has a significant cross-sectional area while still being quite bright. (Link)
Loris, Mar 07 2013

       Just a point, but IR laser range finders can be/are used by long range shooters to adjust for bullet drop, but not as a sight. In the case where a shot is being set up at a known target (window, doorway etc), the shooter can use the range finder to determine the range and use that to adjust an optical sight.   

       Fortunately range finders are a lot better at knowing exactly where and when to look for their own pulse than the human eye.
MechE, Mar 07 2013

       IR range finders are a horse of an entirely different invisible color. They have a mechanical eye that sees _only_ the output spectrum, making it rather easy to pick out the return since they're literally blind to everything else. They can still be spoofed by hot metal surfaces or a sheen of condensation, however.
Alterother, Mar 07 2013


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