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Drone shooting frikkin' laser
http://www.x404.co.uk/forum/viewtopic.php?f=19&t=17994		 Page 1 of 2
Author:  pcernie [ Tue Jan 08, 2013 3:00 pm ]
Post subject:  Drone shooting frikkin' laser
http://www.bbc.co.uk/news/technology-20944726

:shock:
Author:  jonbwfc [ Tue Jan 08, 2013 3:16 pm ]
Post subject:  Re: Drone shooting frikkin' laser
I was reading something about that a few weeks back (just as the trial was due to be happening I think). They reckon in a year or so they'll have doubled the power of the laser on a same size chassis. Statement was that in the same period they'll be able to fit the whole thing in a reasonably sized military vehicle (say an APC) without an external power supply required.

Scary business, especially if you're a chopper pilot. Who knew Moore's law applies to frikkin' lasers?
Author:  JJW009 [ Tue Jan 08, 2013 3:24 pm ]
Post subject:  Re: Drone shooting frikkin' laser
Wonder how it copes with mirrors - bounce that energy right back at you, like a cat's eye?
Author:  pcernie [ Tue Jan 08, 2013 3:26 pm ]
Post subject:  Re: Drone shooting frikkin' laser
I blame George Lucas, you know...
Author:  jonbwfc [ Tue Jan 08, 2013 4:16 pm ]
Post subject:  Re: Drone shooting frikkin' laser
JJW009 wrote:
Wonder how it copes with mirrors - bounce that energy right back at you, like a cat's eye?

In the end it would depend how good the mirror is - it needs to reflect enough of the energy the laser is dumping on it for the mirror surface not to char by the time the round arrives at the target, because once the surface chars its game over. A better bet might be to increase the spin rate of the projectile so the laser doesn't spend long enough on one spot to be able to melt the casing. of course what the other side then does is just increase the wattage of the laser some more...

Actually reflecting the laser back at the sender? Really tricky. You'd need to be able to detect the angle the laser was hitting from and adjust the surface it's striking to be 90 degrees to the beam, or very close to it, all while the laser is burning off the reflective coating. Easier to have a drone fitted with laser seeking missiles - as soon as the drone feels a bit warm it punts a missile off that follows the beam back to source and *bang*.

You could even have the drones working in teams - a couple of decoys flying around waiting for the laser to take a shot at them and a couple of others with seeker missiles waiting for it to happen. Drones are cheap, after all (well, ish). We used a similar tactic to take out Saddam's anti-air stuff back in the day.

It's all a nice new arms race :).

However I suspect this system isn't really intended to take out a sophisticated high tech enemy. It's designed to deal with the kind of stuff 'insurgent' forces tend to throw at your NATO troops in the various hell-holes they get involved in. Dumb artillery, makeshift mortars and RPGs, not a swarm of 21st century killer droids.
Author:  JJW009 [ Tue Jan 08, 2013 4:29 pm ]
Post subject:  Re: Drone shooting frikkin' laser
jonbwfc wrote:
JJW009 wrote:
Wonder how it copes with mirrors - bounce that energy right back at you, like a cat's eye?

In the end it would depend how good the mirror is - it needs to reflect enough of the energy the laser is dumping on it for the mirror surface not to char by the time the round arrives at the target, because once the surface chars its game over. ...

Actually reflecting the laser back at the sender? Really tricky. You'd need to be able to detect the angle the laser was hitting from and adjust the surface it's striking to be 90 degrees to the beam, or very close to it, all while the laser is burning off the reflective coating.

Agree about the high quality required, but it's not impossible. If it was impossible then you couldn't build the weapon.

For targeting I was suggesting something like a cat's eye:

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

You can even get retroreflective paint, although I doubt it would ever reach the required efficiency.
Author:  jonbwfc [ Tue Jan 08, 2013 5:10 pm ]
Post subject:  Re: Drone shooting frikkin' laser
JJW009 wrote:
Agree about the high quality required, but it's not impossible. If it was impossible then you couldn't build the weapon.

The weapon isn't a projectile though. You'd need the mirrors to survive actually being fired out of a barrel.

JJW009 wrote:
For targeting I was suggesting something like a cat's eye:
http://en.wikipedia.org/wiki/Retroreflector
You can even get retroreflective paint, although I doubt it would ever reach the required efficiency.

Ah, d'you know I never knew until now how cat's eyes actually worked.

I think (retro)reflective coatings are a possibility on large drones or such. More doubtful on projectile ammunition and especially if it's being carried around by the kind of militia/insurgent force I mentioned above. This is, as always with military thinking, a weapon to defeat the enemy they are fighting now, not the enemy they may fighting in the future.

Jon
Author:  l3v1ck [ Tue Jan 08, 2013 8:55 pm ]
Post subject:  Re: Drone shooting frikkin' laser
Presumably it could shoot down normal aircraft too? Although the ofter fly at much higher altitudes, but even so....
Author:  jonbwfc [ Wed Jan 09, 2013 12:21 am ]
Post subject:  Re: Drone shooting frikkin' laser
l3v1ck wrote:
Presumably it could shoot down normal aircraft too? Although the ofter fly at much higher altitudes, but even so....

The altitude matters a lot. The rate at which the energy the laser dumps onto the target drops off is a function of the square of the distance between the emitter and target, and that's without clouds or etc. Double the height, quarter the power. Plus the farther away the target is the more accurate the turret has to be to keep the laser on the target. That's why they're using it as a point defense system - whatever they're firing at is coming towards them, so the laser turret is getting more effective as it goes.

Plus they can't legally use it on piloted planes anyway - using laser weapons against people is considered to be against protocol one of the Geneva Convention. Doing so is considered a war crime.
Author:  Amnesia10 [ Wed Jan 09, 2013 5:12 am ]
Post subject:  Re: Drone shooting frikkin' laser
l3v1ck wrote:
Presumably it could shoot down normal aircraft too? Although the ofter fly at much higher altitudes, but even so....

Drone can also fly a lot higher than officially stated. This will become the must have accessory for middle eastern weddings, considering so many people are targeted at Pakistani and Afghan weddings.
Author:  JJW009 [ Wed Jan 09, 2013 10:50 am ]
Post subject:  Re: Drone shooting frikkin' laser
jonbwfc wrote:
Plus they can't legally use it on piloted planes anyway - using laser weapons against people is considered to be against protocol one of the Geneva Convention. Doing so is considered a war crime.

I thought that was only if they were designed to mame(sp?) rather than kill? That is, lower powered lasers which can blind.
Author:  cloaked_wolf [ Wed Jan 09, 2013 11:09 am ]
Post subject:  Re: Drone shooting frikkin' laser
Maim
Author:  Spreadie [ Wed Jan 09, 2013 11:15 am ]
Post subject:  Re: Drone shooting frikkin' laser
JJW009 wrote:
jonbwfc wrote:
Plus they can't legally use it on piloted planes anyway - using laser weapons against people is considered to be against protocol one of the Geneva Convention. Doing so is considered a war crime.

I thought that was only if they were designed to mame(sp?) rather than kill? That is, lower powered lasers which can blind.

It's maim - you've had one too many arcade emulators! :D

Doesn't the laser need to radiate the target for a sustained length of time? Point defense against incoming missiles is problematic, with missiles programmed to pop-up and jink as they approach; and the closing speed. Probably fine for drones as the article states, but it'll be interesting how they develop this.
Author:  JJW009 [ Wed Jan 09, 2013 11:25 am ]
Post subject:  Re: Drone shooting frikkin' laser
Spreadie wrote:
Doesn't the laser need to radiate the target for a sustained length of time?

A primary design objective is to concentrate the energy into as short a burst as possible, in order to maximise the power. They've managed many gigawatts into less than a microsecond.
Author:  JJW009 [ Sat Jan 12, 2013 9:37 am ]
Post subject:  Re: Drone shooting frikkin' laser
Meant to post this before: http://www.bbc.co.uk/news/technology-18630622

Quote:
50 billion watts

A weapon which can fire a laser-guided lightning bolt at a target

"During the duration of the laser pulse, it can be putting out more power than a large city needs, but the pulse only lasts for two-trillionths of a second."

"We use an ultra-short-pulse laser of modest energy to make a laser beam so intense that it focuses on itself in air and stays focused in a filament,"

"If a laser beam is intense enough, its electro-magnetic field is strong enough to rip electrons off of air molecules, creating plasma," Mr Fischer said.

"This plasma is located along the path of the laser beam, so we can direct it wherever we want by moving a mirror."


I remember sketching out such a weapon about 30 years ago, but making it real is cool :D
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