Laser vs UAV: No Fair Fight Here

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TallDave
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Post by TallDave »

You'd need a hella fast PID loop. But missile-to-missile interceptors were once thought to be impossible for the same reason. I think Moore's Law will ultimately win here.
n*kBolt*Te = B**2/(2*mu0) and B^.25 loss scaling? Or not so much? Hopefully we'll know soon...

ladajo
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Post by ladajo »

There exists already lasers that successfully target and defeat mortars and artillery shells.

We have wonderful systems that detect, slew and track to high degrees of precision over long ranges.
But, I do agree with Tom's point that effects on target are the key. With a small beam low power laser you are a$$ out. But CIWS is the same. You do not drive a laser beam of bullets into the target, you dither it with a wall of crap it flys into.

The idea of precision fire with CIWS is silly, for example, try and shoot the engines of an attacking small craft, and you will shred the boat in total. it is not meant to work that way.

When they tested the laser against the ROV boat, it was from a ship to a moving target at over a mile. Cook through was not instant, but it did work, and did defeat the engine.

Are lasers ready for any fight? No. Are they fast getting there? Yes.
What we can't do with precision, we can do with power. That is what ABL does. Precision and power in one package gives it a LONG reach. If I can put it in an aircraft, I can put it on a ship. And with that thing I can turn any hostile boat driver into a "Screaming Alpha" in short order.

DeltaV
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Post by DeltaV »

Depending on the warhead design and hardness of the target, a non-nuclear missile might well be lethal when detonating quite a ways out. Not a mile, but maybe on the order of 100 meters or more. Tom has a valid point about farther-out missile kills requiring much greater accuracy and precision for lasers and other narrow beams.

But in the long run, I suspect it will be phased arrays that deliver the punch, across large distances, using a wide spectrum to find weak spots in the missile's reflectivity. While the circuits and algorithms controlling the beam will still have some intrinsic overshoot, as with any closed-loop control system, it will be far, far less than would be seen with a mechanically-slewed emitter. Mechanical inertia would not be a factor, allowing extremely fast beam slew with an essentially "deadbeat" (negligible overshoot) convergence on target. The beam pattern can be shaped as needed. Multiple simultaneous beams are also doable, as done today with AESAs.

I can also envision a system where the platform under missile attack fires a charged-particle beam "shotgun", not to kill the missile, but just to give it a significant charge as it flies through the wide beam. Then a tighter, higher-power beam of the opposite charge would be aimed and fired, attracted to the charged missile in the final meters, easing targeting requirements. Charged beams have their own set of problems, however. It might end up as simply a fusion-powered neutron beam with enough spread to ensure a hit. Particle beams AFAIK are not easily done with phased arrays, so then you are forced to use magnetic and/or electrostatic beam steering (with charge stripping for the neutron beam), but still no mechanical inertia other than the particles themselves.

Skipjack
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Post by Skipjack »

I dont quite see what difference it makes whether you use said laser against a UAV or a manned jet. You can build a UAV any size and you can certainly use the wight savings from cockpit, life support, ejection seats, etc to better shield vital parts against laser attacks.
There are other factors about DEWs that limit their effectiveness. Averse weather conditions come to my mind. If the laser is not of the strong kind then some thick fog will ruin its day.
Another issue is line of sight. If your UAV flies low and stays out of the direct line of sight of the laser or only enters it for very short periods of time, then the laser will be ineffective.
Someone already mentioned reflective coating. That is definitely going to protect against some types of DEWs.
That said, DEWs are an interesting technology, but I dont think that they will affect whether we use more or less UAVs one way or the other.

krenshala
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Post by krenshala »

Skipjack wrote:There are other factors about DEWs that limit their effectiveness. Averse weather conditions come to my mind. If the laser is not of the strong kind then some thick fog will ruin its day.
Actually, this all depends on the frequency selected for the laser.
Skipjack wrote:Another issue is line of sight. If your UAV flies low and stays out of the direct line of sight of the laser or only enters it for very short periods of time, then the laser will be ineffective.
Less effective definitely, but not always ineffective. There are solutions to this as well, however. The simplest is an airborne platform (aircraft, drone, zeppelin, etc). Circumstances play a big role here, of course, as it is expensive to maintain such a platform on a long timescale especially when a target for you laser may not even exist.
Skipjack wrote:Someone already mentioned reflective coating. That is definitely going to protect against some types of DEWs.
That said, DEWs are an interesting technology, but I dont think that they will affect whether we use more or less UAVs one way or the other.
I'm definitely in agreement with you here. ;)

Tom Ligon
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Post by Tom Ligon »

Large zeppelin with a laser. Like this? http://www.mav6.com/Mav6-Blue-Devil-Airship.pdf

Must ... resist ... temptation ... to ... say ...

Help me, Larry.

Here's the deal. DEW certainly have their place in defense, particularly against aircraft. Their very existence requires that countermeasures be developed. If they are very dangerous to aircraft, that argues in favor of expendable aircraft and stealth aircraft. Small stealthy UAVs would be able to get close before being detected. If the DEW can't see it, it can't shoot it down.

I might suggest you also need enough decoys to keep the DEW busy, and probably jamming to blind it. And I see no reason why small, hard-hitting weapons can't be made stealthy. Up against DEWs that will be necessary.

But DEW won't gather intel about what's going on on the ground. For that you want satellites (which can be blinded by lasers), UAVs, big blimps full of toys, manned aircraft, and a few special forces types with cahones the size of canteloupes and good at making gillie suits. And then you need offensive forces to kill people and break their stuff.

No one system. You need it all. And particularly you need the logistics to get there firstest with the mostest. And you need to deny all this stuff to the other side because obviously this stuff is dangerous to our side.

ladajo
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Post by ladajo »

I agree. You need a mix of stuff. No one magic bullet, all purpose system has ever existed.

DEW has its place as part of a layering of systems for many reasons, some of which already mentioned above, and others not.

In a sense we are already using directed energy with phased array systems.

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