Targeting with Ballistic Projectile

[MrSamosa]

After watching the news from Iraq, I frequently hear the reporters saying things along the lines of, "We have been taking in bound mortars, so we need to move from this position. The first two mortars were off, but what the Iraqis do is fire three mortars that are off, but then the fourth one is dead on."

That basically sums up how it works. Apparently, when firing mortars, the Iraqis "Triangulate" the enemy's position... The first mortar may be too far to the north, the next one too far to the east, the third too far South-West, but the fourth is directly on target.

Does anybody know how this works? Are there some calculations that the Mortar Teams do?

This would be very interesting, because it provides a very cheap way to have dead-on aim. The US Military likes to put GPS guidance systems and airbrakes in things as seemingly simple as an artillery shell! However, the "Triangulation" that the Iraqis do seems so much easier and cheaper. Furthermore, this could be applied to other ballistic projectiles, like Short Range Missiles. They would be fired in groups of four...

The first three would be fired with an observer monitoring where they land, and he would report that back to the fire-team. The fire-team, in turn, makes that one crucial calculation, and the fourth missile would hit dead on. But does anyone know how this is done???

[firebreether]

Doesn't sound like it works all that good, if the people you are firing at know that they have a good chance of being toast, and leave before you ever get the chance to fire that fourth shot. In most applications that i can think of, you need to be dead on the first time.

Are you absolutely sure that they dont just guestimate the launch of the first one, then just try to adjust until they hit dead on, and that it just generally takes four shots to get it dead on?

Seems to me, that you dont need to triangulate, but rather, it is easy enough to aim dead for a target laterally, bit getting the range perfect is the tough part. So if you fire one shot a little too far, and one shot a little to close, you have a prety good guess as to get the range just right on the next shot.

Wind will affect a missile alot more than a mortar shell, so if there is a high wind, it would be really tough to get the missile to aim prefectly at all.

[Tuatara]

From what I've heard it is common for artillery to rely on a forward observer to correct aim. I'd imagine there are many things that would affect the trajectory of a shell - wind, temperature, air pressure, gun temperature, shell propellant temperature ....

If you think about it, it should be a reasonably simple linear algebra problem. You've got two unknowns - elevation and azimuth - so you need three equations, hence three range finding shots.

Seems a bit tough on your ammo stockpile, if you can only get 25% on target :p

[Ghostcustom 24]

Actually, to the best of my knowledge 25% hits is not to bad for a mortar. Especially when you have a moving target. In that case I imagine it usually comes down to luck and/or skill and experience.

I know some people whom I can ask how the U.S. works their mortars. I will get back to you guys tomorrow.

[Microtek]

Well, when I was in the army I was the one doing the calculations for a section of 81 mm mortars so I can explain:
The observer spots a target which needs to be reasonably stationary ( say an infantry platoon ), he then finds their exact position using a map and calls the fire direction team ( FDT ) giving them this position and requesting a certain amount and type of shelling on that position.
Now, the FDT have already measured the prevailing wind and using this data to correct the simple ballistic arc of an inert projectile, they fire one or two shells from the center mortar. Because there will always be variables that cannot be known, the shell will not ( usually ) fall exactly as calculated so the observer notes where it went in relation to the target. He then requests another ranging shell - if the first shot fell too short, say by 40 meters, he will generally ask the FDT for another shell to go forward 60 or 80 meters in relation to the last setting. This improves the chances of hitting with the third round ( which will then be fire-for-effect; all the mortars firing a pattern of 6-15 shells ) and tends to pin the enemy better than two shells on the same side.

[Ghostcustom 24]

Well, that is just about what I was told except that I asked about a single mortar team and I got the impression that if ammunition was not a factor then they would keep adjusting the mortar as they fire (pumping out as many as possible).

[Gargoylebrother]

Actuall when fireing a mortor what you do is use perdetermined targets when avaliable and then all you do is adjust accordingly. But if you dont have any perdetermined targets then what you do is gage the range of the target and fire a shot and see where it hits by use of a spotter if the round hits say 200m to the south and 100m to the west then all you do is adjust your mortor for the diference. its perty much guess work and some good math. Also on the 3 shot thing it takes about on adverage 3 shots to set the baseplate on a mortor the base plate is a large heavey statoinary plate that once its set deeply enough into the ground its not moving easily once its set you know the mortor isnt moving you can accuratly adjust the mortor for range and winddrift. Thats why it takes 3 or so shots before they can hit there target. Also on another note mortors are damn sweet with a small mortor battery of 4 mortor you can put off more firepower than a large battery of 105s but with siginfetly less range.

[Leadazide]

Firebreather said
-< Doesn't sound like it works all that good, if the people you are firing at know that they have a good chance of being toast, and leave before you ever get the chance to fire that fourth shot. In most applications that i can think of, you need to be dead on the first time. >-

First of all it's rarelly that 4 shells are used to get the aim right. While I was in the army on a 81 mm morter, we usually had the target with 2 shells and fired for effect on the third....and that in less then 3-4 min, depending on the range.

Second of all I would never leave my foxhole or any other cover while shells were falling around me!! I would just lay low and pay to what ever god that was willing to listen that no shell hit my hole!!