Army's new mobile laser can shoot down mortar rounds.

[Bagpuss]

Even if this can do what it claims with it being automated how long before it takes after the patriot system and starts shooting down low flying friendly aircraft... :\

 

[tarchon]

If it generates heat there might also be a longer cooldown time after rapid use of the laser or the need for large cooling systems. Also, how much chemicals do these lasers use? If it uses large quantities these system will use many supply ressources. You can't really send a supertanker with chemicals into a region where such systems are neccessary.

That would require some big computer power. Vector calculation isn't a easy thing especially with so many variables like weather and wind you can't ignore because of the small size of the target. Especially when multiple rounds are fired from both sides this system will loose valuable seconds to determine which rounds are safe and which not.

You're right on about the laser - firing rate is going to be a significant challenge, not only from the heat issues. It's a notorious problem with chemical lasers, and that's been one of the key barriers to directed energy weapons. Another thing is that I'd hate to be a guy standing around when the deuterium fluoride tank gets hit by shrapnal. DF gas exposure can be an extremely unpleasant way to die. One will also note from reading DoD solicitations that detection of hazardous gas leaks is an area of substantial interest right now.
The computer power isn't such a big issue with single rounds, though I totally agree that a full artillery barrage would be rather challenging. I think they envision this initially as being more of a defense against artillery pot-shots on bases and compounds, like what they get from insurgents in Iraq. In the more advanced stages, I think they're looking for a system to defend mobile armor, in which cases they're unlikely to need to fire very often. There's actually some interesting work in figuring out how to prematurely detonate armor piercing rounds without requiring the immense pulse energies in something like MTHEL. You don't really have to destroy one of those to make it ineffective - you just have to make it blow a couple milliseconds early to mess up the plasma shaping.

 

[Aaron2]

Also it isn't as easy as saying "missiles comming towards me". Computers are stupid. Coming towards me is nothing a computer understands. A computer understands it when the round reduces its distance to a specific point. That will work but isn't very exact.

With doppler shift detection, the radar knows instantly whether the round is approaching or receding from the antenna. It does not need to track changes in the target's position. Its the same principle used to catch speeders. The radar used by the police does not track the positions of the individual cars to determine if they are speeding. It just uses their dopplar shift.

A setting to low and the system will fire at round which pose absolutely no threat or are fired by your own troops nearly parallel to the radar. A setting to high and the system would ignore rounds which aim at one of the flanks.

This would only be a problem with rounds fired perfectly parallel (sp) to the front line. I can't imagine that happening much. For the system to work it only needs to target shells approaching itself. The guys off on your flanks have their own defenses.

Maybe I underestimate the current computer technology, but unlike the excisting systems, time is very cruical here. All this calculation have to be done before the round is to close to be intercepted. You also need some data from the round like speed, vector, how much it is affected by wind, weather and air resistence to calculate the flight path. I guess unless the flight path is rather flat (missiles) such calculation can't really begin untill the round is near its highest point if the calucaltion should be exact. If only the general area should be calculated it gets easier, but if the round is hostile, the exact path for targeting has to be calculated again.

Your making this out to be more complicated than it is. The targeting computer doesn't have to calculate the exact impact point of the round. It only needs to guess where the round will be one tiny fraction of a second in the future; the time it takes for the laser beam to reach the target.


Aaron

 

[Pagan priest]

Radar and computer technology has been available for a couple of decades now that can easily determine all relavant data about an incoming artillery shell is a very short (frction of a second) time. I got out of the Navy in the 80's and the Phalanx missile defense system was on just about every ship back then.

The only tech breakthroughs needed here are in the laser itself. Things like the ability to fire rapidly at multiple targets and deliver enough energy to kill the incoming threat.

 

[DM_Matt]

One of the original concrete uses that the THEL was intended for was to be deployed on the border between Israel and Lebanon to defend against Katushya rockets fired by Hezbollah. For that use, it would have to shoot down multiple small, short-range missiles.

 

[Heretic Apostate]

Okay, haven't read all the responses, but...

Anyone remember some of those anti-ballistic tests done for some missile system? They had the missiles fly from a preset position, to a preset destination. Then, the anti-missile system only had to catch the enemy missile along a preset path, and whammo! Success!

Which rarely happens in the field. The enemy isn't going to tell you where they're firing from and where their target is, as well as when they're firing, to give you time to position your defenses and know where to look for the enemy missile.

I'm highly suspicious of this test. Did they test it from a number of different positions, firing at unspecified targets, at unpredictable times? That would be my first question... Otherwise, we just have another defense contractor that could be falsifying data to win the contract, then planning on selling the "patch" after production has started.

 

[Krieg]

anti-ballistic tests done for some missile system? They had the missiles fly from a preset position, to a preset destination. Then, the anti-missile system only had to catch the enemy missile along a preset path, and whammo! Success!

Hopefully you do realize that those type of tests are only one step in the R&D process. They are quite usefull for generating baseline performance data and are always followed by more diverse & challenging "real world" tests.