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Artillery: EQ-36 Goes To War
   Next Article → PROCUREMENT: Free, With Strings
September 18, 2010: Two years after the U.S. Army successfully tested its new EQ-36 artillery and mortar finding radar, the first one is being sent to a combat zone (Afghanistan). Easier to use and repair, as well as more reliable than its predecessor (the AN TPQ-36/37), the EQ-36 will also be able to scan all around (360 degrees), rather than just 90 degrees (as with the current system,) and be faster as well. The army wants to buy at least 180 EQ-36s, for about $9 million each. But so far, the army only has money to buy 33 of them.

The older FireFinder (AN TPQ-36/37) radar has gotten a bad reputation over the last few years. That was often for failing to detect incoming mortar fire. FireFinder was developed in the 1970s, based on Vietnam experience with enemy mortar and rocket attacks.

FireFinder is a radar system which, when it spots an incoming shell, calculates where it came from and transmits the location to a nearby artillery unit, which then fires on where the mortar is (or was). This process takes 3-4 minutes (or less, for experienced troops.) FireFinder worked as advertised, but got little use until U.S. troops entered Iraq. Since then, the FireFinder has been very effective, and heavily used. Too heavily used. There were not a lot of spare parts stockpiled for FireFinder, and several hundred million dollars worth had to be quickly ordered. The manufacturer has also introduced new components, that are more reliable, and easier to maintain.

Meanwhile, existing FireFinders are often failing to catch incoming fire, either because of equipment failure, or because the enemy is using tactics that fool the radar. For example, in Iraq, American bases are generally on higher ground than the mortars firing at them. Putting bases on the high ground enables you to watch more of the surrounding terrain. But FireFinder needs a line-of-sight to get a good fix on the firing weapons position. If the mortar is too far below the radar, FireFinder cannot accurately spot where the fire is coming from.

Another problem is that if the mortar is too close, FireFinder is much less likely to quickly determine where the fire is coming from. So the enemy mortar teams get as close as they can before firing. This still makes the mortar teams vulnerable to counterattack by coalition troops, but not the immediate (in a few minutes) artillery fire that FireFinder can make happen under the right conditions.

At first, the army was going to halt further upgrades on FireFinder, which, after all was developed over thirty years ago, and begin developing the EQ-36, a new system that can better deal with the kinds of problems encountered in Iraq. But FireFinder has been so useful, that new upgrades were pursued anyway, while work continued on the EQ-36. The upgrades have also been made available to other users of FireFinder (including allies in the Middle East; Egypt, Israel, Jordan, Saudi Arabia and Turkey.) FireFinders are still doing most of the work out there, and it will be several years before EQ-36 replaces a significant number of them.

 

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shep854       9/18/2010 7:46:54 AM
"Bad reputation", "Worked as advertised", "Has been so useful"...So which is it?  Two out of three ain't bad?
 
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WarNerd       9/18/2010 2:30:34 PM

"Bad reputation", "Worked as advertised", "Has been so useful"...So which is it?  Two out of three ain't bad?

It worked exactly the way it was designed, but it was not designed to do all the things it is being called on for now.  In some situations it is sufficient, in others worthless, and for most somewhere in between.
 
An analogy would be that a shovel can do most digging jobs, but sometimes a backhoe is better.
 
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Privateer       9/18/2010 3:51:54 PM
Since when does Firefinder (or any other counterbattery radar, for that matter) require a line-of-sight to get a fix on the firing weapon's position?
 
The radar needs to detect a projectile during its upward trajectory prior to reaching apogee, track its flightpath for a while, derive a trajectory and extrapolate the firing weapon's position as well as the projectile's impact point. That means that the system can also plot positions located behind hills.  The problem is that high hills also raise also the "search fence", which in turn reduces the probability of acquiring targets.
 
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WarNerd       9/19/2010 5:51:39 AM

Since when does Firefinder (or any other counterbattery radar, for that matter) require a line-of-sight to get a fix on the firing weapon's position?

The radar needs to detect a projectile during its upward trajectory prior to reaching apogee, track its flightpath for a while, derive a trajectory and extrapolate the firing weapon's position as well as the projectile's impact point. That means that the system can also plot positions located behind hills.  The problem is that high hills also raise also the "search fence", which in turn reduces the probability of acquiring targets.

 
As I understand the older designs transmit to planes of signals at different angles above the horizon and take the range and bearing of the shell as it passes through each.  If that is correct, then if the launcher is far enough below the Firefinder, or close enough to the target and using a reduced charge, then the trajectory may peak below the second plane.
 
The new design is undoubtedly a phased array and can collect data points from most of the trajectory, including the descent, eliminating the hole in coverage.
 
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shep854       9/19/2010 9:43:19 PM



"Bad reputation", "Worked as advertised", "Has been so useful"...So which is it?  Two out of three ain't bad?



It worked exactly the way it was designed, but it was not designed to do all the things it is being called on for now.  In some situations it is sufficient, in others worthless, and for most somewhere in between.
 

An analogy would be that a shovel can do most digging jobs, but sometimes a backhoe is better.
 
That's the point I was trying to make.  Thanks for saying it with more clarity. 


 
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radarman44       9/21/2010 1:50:11 PM
The older FireFinder radars (Q-36 and Q-37) are phased array doppler radars. The problem with detections is the amount of time the round is in the track beams. There must be a certain amount of track time of the rounds before the radar can determine the trajectory so it can extrapolate back to the firing point and forward to the impact point. When the mask is too high or the firing point is too close, there is not enough time to track the projectile, or the projectile is not in the radar coverage long enough, thus it gets dropped. This is not a new phenom, we have known this problem existed since the early '80's. We just utilized multiple radars, in depth, to cover the same area and had overlapping search sectors. In the nonlinear battle fields of today, this is not feasable because of the limited amount od radars in the Army inventory.
 
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