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

[Dark Jezter]

From looking over the technical information (not that I understood much of it) it looks to me that this system isn't designed for close range mortar protection but for long range missile protection.

Long range missile protection? The factsheet that Tharchon linked to quite clearly stated that it was started to defend against short-range artillary rockets (like those fired from an MLRS platform). The ability to intercept mortar rounds is an evolution of the system.

It also looks like, even in the future variant shown in the information, that it would be ineffective in mortar defense as mortar round fly at much lower heigh (uneducated guess) and this system needs a clear radar lock to be effective

It's a proven fact that mortar rounds can be tracked by radar. In fact, the current application of this technology allows one side to track the incoming rounds and determine the source of the fire, so they can then launch their own strikes in retaliation.

How fast do you think can this thing lock on and destroy a bullet? Enough time for a mortar to shoot another round?

I'm not getting what you're trying to say here.

Also, if the army really uses this system, they imo have to equip all of their missiles and rounds with friend or foe emitter so that it doesn't shoots down the wrong projectiles.

That occured to me as well, but there could be other alternatives: The tracking software could be programmed to calculate where artillery rounds are going to land based on altitude, direction, and speed (taking other factors into account such as humidity and wind). This would allow it to target and intercept only rounds that would land in a certain area, and ignore rounds that land outside the area it's programmed to protect.

 

[Umbran]

A "critical reader" would understand that a press release conventionally doesn't contain a lot of technical details, many of which are either proprietary or classified to begin with.

Yes. But at the same time, a critical reader who remembers the "Star Wars" weapon debacles of the 1980s won't assume the technical details are as they really should be. Especially on high-end, expensive weapon systems. They may be perfectly legit. They may not be. But you don't assume the better of the two, unless you like wasting a few billion dollars.

I happen to know that steering a laser beam and tracking a mortar with radar are much easier to do than precisely directing a mortar into the beam of a pulsed laser

Quite possibly. Though under low-wind conditions the path of a mortar shell is pretty darned predictable. Otherwise, the mortar would be unable to hit a chosen target. In either case, it'd be even easier to hit the mortar if you know the launch location and expected flight path of the projectile beforehand.

If you really must know exactly how they did the tracking, rather than complain about what uncritical dufuses we are

I didn't call anyone a dufus. Please refrain from putting words in my mouth.

Casual acceptance of incomplete reports on technical matters is an unfortunate habit of our society. It has cost our nation a great deal in money, time, and resources. It will continue to do so if nobody ever points out the error.

Note how my simple questioning of the incomplete report has brought up someone who apparently has some knowledge of the technology, and quickly yielded up more complete information? You may call it rude. I call it a cautionary note that seems to have had constructive results.

 

[tarchon]

From looking over the technical information (not that I understood much of it) it looks to me that this system isn't designed for close range mortar protection but for long range missile protection.

"By now the THEL Demonstrator has engaged and destroyed a large number of artillery rockets in mid-flight in an extended series of demonstration tests at the US Army’s White Sands Missile Range in New Mexico."
It's very distinctly an anti-artillery system. Looks like they do a handoff from radar to laser-optical tracking in the late stages of target acquisition. Radar resolution is just barely adequate for targets in this size range, which is why laser tracking has generated so much interest. Long-range anti-ballistic missile systems use a similar sequence of handoffs.

 

[Aaron2]

It also looks like, even in the future variant shown in the information, that it would be ineffective in mortar defense as mortar round fly at much lower heigh (uneducated guess) and this system needs a clear radar lock to be effective (nothing you really have in the battlefields of the present like various cities in Irak)

Actually, using dopplar processing, its fairly easy for a radar to pick out a moving object among ground clutter. Of course, you need line of sight and cities are, as you said, the worst.

There are planes with side scanning radars that, using GMTI and GMTT (Ground Moving Target Tracking) algorithms, can track hundreds of moving ground targets from the air. Things like trucks, tanks, and ships.


Aaron

 

[tarchon]

Note how my simple questioning of the incomplete report has brought up someone who apparently has some knowledge of the technology, and quickly yielded up more complete information? You may call it rude. I call it a cautionary note that seems to have had constructive results.

Yeah, it's a good thing you managed to scare up a laser scientist to type the name of the system from the article on the Google search input.

 

[Derren]

Long range missile protection? The factsheet that Tharchon linked to quite clearly stated that it was started to defend against short-range artillary rockets (like those fired from an MLRS platform). The ability to intercept mortar rounds is an evolution of the system.

Mabye long range was the wrong word, but imo those missiles they have used as target practice are fired at a much larger distance than a mortar is. A MLRS isn't exactly short range.

I'm not getting what you're trying to say here.

Would the system be able to
- Detect incomming mortar rounds.
- Calculate the flight path of multiple rounds to detect the most dangerous round (or the round not fiered by an ally)
- Lock onto this round.
- Physically targeting the round.
- Destroy the round. (I don't think the round will explode as soon as the laser hits)
- Repeat to step 1.

Before the mortar can fire another round? If this is not the case, this system may destroy the first three or four rounds, but the fifth will reach the target.
I'm not sure if this is fact or fiction, but does a laser generate heat when fired or only at the target? 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 occured to me as well, but there could be other alternatives: The tracking software could be programmed to calculate where artillery rounds are going to land based on altitude, direction, and speed (taking other factors into account such as humidity and wind). This would allow it to target and intercept only rounds that would land in a certain area, and ignore rounds that land outside the area it's programmed to protect.

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.

I see this system mainly as ship defense system as missiles are imo the main threat in modern naval combat and the missiles used in ship combat are large enough that a FF emitter won't cause much problems (if those Tomahawks etc. don't already have such a thing). Also, ships can hold the chemicals more easily than mobile ground vehicels because of their size.
Only the unstable platform might cause problems with aiming.

If this system really becomes useable it is a big step forward in military laser use and a more offensive laser system might follow, especially as with it a defense against missile and bombs excists.

 

[Aaron2]

- Calculate the flight path of multiple rounds to detect the most dangerous round (or the round not fiered by an ally)

I don't think that determining whether its a friendly round or not is a problem, just target the rounds that are coming towards you.

I see the biggest problem as the time it takes to heat the round until it explodes. The faster the round moves the more cooling from wind. Plus, spin stabilized rounds will take longer to heat up. Fin stabilized, slow moving mortar rounds seem ideal targets. Especially since they are causing so much trouble in Iraq.

Aaron

 

[Dark Jezter]

Would the system be able to
- Detect incomming mortar rounds.
- Calculate the flight path of multiple rounds to detect the most dangerous round (or the round not fiered by an ally)
- Lock onto this round.
- Physically targeting the round.
- Destroy the round. (I don't think the round will explode as soon as the laser hits)
- Repeat to step 1.

Before the mortar can fire another round? If this is not the case, this system may destroy the first three or four rounds, but the fifth will reach the target.
I'm not sure if this is fact or fiction, but does a laser generate heat when fired or only at the target? 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.

The article stated that the THEL was tested successfully against salvo fire, meaning that it's capable of rapidly intercepting multiple mortar rounds.

I'm not certain about the heat issue.

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.

We already have radar systems with tracking software that can use the vector of incoming artillery fire to determine the point of origin, and those systems have been around for over a decade. Using that technology (and considering that computing power has improved exponentially since then), it would be simple to write up software that could predict the destination of incoming fire. Heck, I'd be really surprised if it hadn't been done already.

I see this system mainly as ship defense system as missiles are imo the main threat in modern naval combat and the missiles used in ship combat are large enough that a FF emitter won't cause much problems (if those Tomahawks etc. don't already have such a thing). Also, ships can hold the chemicals more easily than mobile ground vehicels because of their size.
Only the unstable platform might cause problems with aiming.

The Navy already has effective anti-missile defenses. In fact, one of the main purposes of the Aegis Cruiser is to shoot down inbound anti-ship missiles with its own SAM missiles guided by the ship's very powerful SPY radar system, and if the missiles manage to get past the SAMs, many ships have fully-automated chainguns (capable of firing hundreds of rounds per second) designed to wipe out any missiles that get close.

Although the THEL system could also be easily adapted to defend ships against inbound threats.

 

[Derren]

Only that Irak isn't the kind of area this system would be much of use because of the city battlefields.

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.
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.

And that is only when the system and the defending area are stationary. If one or both things are mobile, things get much more complicated.

We already have radar systems with tracking software that can use the vector of incoming artillery fire to determine the point of origin, and those systems have been around for over a decade. Using that technology (and considering that computing power has improved exponentially since then), it would be simple to write up software that could predict the destination of incoming fire. Heck, I'd be really surprised if it hadn't been done already.

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.

The Navy already has effective anti-missile defenses. In fact, one of the main purposes of the Aegis Cruiser is to shoot down inbound anti-ship missiles with its own SAM missiles guided by the ship's very powerful SPY radar system, and if the missiles manage to get past the SAMs, many ships have fully-automated chainguns (capable of firing hundreds of rounds per second) designed to wipe out any missiles that get close.

The laser certainly will not replace SAMs, as its range is so close but depending on the accuracy of the laser I can see how in newer ships this system replaces the chainguns which I imagine as beeing more a system which depends on the mass of rounds to hit anything than on precision.
It all depends on the precision, the range, the ammount of gas and availability of it and if the laser is useable and efficent in all weather conditions.

 

[Dark Jezter]

I see the biggest problem as the time it takes to heat the round until it explodes. The faster the round move the more cooling from wind. Plus, spin stabilized rounds will take longer to heat up. Fin stabilized, slow moving mortar round seem ideal targets. Especially since they are causing so much trouble in Iraq.

IIRC, the laser beam dosen't actually burn through the target. Rather, it's more of a shock effect: all the energy is tranferred from the laser to the target in a few millionths of a second, resulting in an actual explosion capable of utterly destroying the round.

I might be mistaken, however. Any physics buffs here know more about this subject?