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August 17, 2006

Answering the mail, part 2.

Owen asks this question (in the discussion to this post below) and I thought I might as well pull the answer up into the light, especially since answering it took a good chunk of normal blogging time!

I also have a technical question for John. You note that the Israeli guns are accurate and the Katyushas not. Like all rockets, they change trajectory somewhat in the air. But since the Israeli counterbattery radar is following their terminal trajectory, doesn't that mean that a fire control computer calculating backwards from it is unlikely to lead you exactly to the launch site?

Also, since the fire control computer calculates ballistic trajectories, surely there will be an error in calculating rocket trajectories, which only go ballistic after the motor dies?

Presumably, just it's tougher to predict where a projectile will land when it's an inaccurate one, wouldn't it also be tougher to track back to the firing point, the more inaccurate and erratic the incoming projectile was?

So wouldn't accurate counterbattery fire against Katyushas be impeded by the inherent inaccuracy and wobbliness of the Katyushas themselves?

Not a criticism, just a technical question.

[Note to self, always beware Owen when he says... "Not a criticism, just a technical question.", journos are *not* trustworthy... remember that reporter from your wrestling days]

A little yes and mostly no, and it also depends on the ROE.

CF radar catches the rocket/projo on the ascending arc, when the angular error is smaller and there is less cumulative error inherent in the trajectory, which of course gets greater the farther along the trajectory you are. You only catch things on the descending arc (least accurate for backplot to origin) if you are doing impact prediction. As for impact prediction of rockets - by the time they are on a descending trajectory, they are ballistic, and the impact prediction is easy. The problem with using your radars for that purpose is that unlike tracking your *own* rounds, where you know when and from where they're going to be fired, with the rockets you don't know that. With the generally random (to the outside observer) launch site and time, there is a very limited window to catch the rocket, do the impact predict on the descending trajectory -when you have very little time left - and get a warning out.

It's not at all like a SCUD, where you catch them on ascending trajectory, sound the alarm getting people in the military environment moving to shelters - civilians who don't have local, almost in-house shelters are a different story - and can then refine your plot as the missile falls, and thus have a comparatively lot more time.

Accuracy is also enhanced by catching multiple launches from the same location, such as ripple fire, and by multiple radars observing the launch, but I would guesstimate a 50 meter CEP to be an outside ballpark number.

After that, it's ROE. In conventional combat, I'd fire battery volleys on a radar target like that.

In this environment, *if* I had a UAV in the air and close, or an armed aircraft, I'd vector them to try to get eyes on the target to confirm - but since these guys shoot and scoot, that's a very tight window.

War is an ugly business at this point, Owen.

Unless my maps showed a school/church/hospital/culturally sensitive area, and those rockets were headed to my civilian areas, if the attack guidance matrix/ROE allowed it, I would shoot back. If they are hitting my military areas with enough regularity and impact, I would shoot back.

If it was near those sensitive sites, I would be keeping a running log and doing some pattern analysis - and if that turned into a pattern, i.e., shooting from sensitive sites, I would then start orienting assets like SOF, UAVs, etc, to observe those sites and set them up for guided weapons, or, try to occupy the areas.

If I'm taking real casualties from launches from those areas, and I couldn't get assets to get eyes on, I would probably come down on shooting back with single/two gun volleys, and I would have all the documentation I would need to drop on your desk and say "tough noogies, sorry about that, but they're the ones who aren't playing by the Convention - and I am. And do please condemn their violations of the Conventions if you are going to yell at me about them."

And before you launch into a tirade... remember, we're talking about me, in my job as a fire direction officer, defending my targeting and ROE decisions. At that level, the overall question of the war itself doesn't enter into it, so don't go down *that* rathole. 8^)