April 9, 2012: As the U.S. Army replaces its older AN PQ-36/37 FireFinder artillery spotting radar systems with the new and improved Enhanced AN/TPQ-36/37, EQ-36, someone noted that the similarity in the designations for the two systems sometimes caused confusion. It was also noted that the EQ-36 was actually a new design, not an enhanced version of the older one. So the EG-36 has received a new designation: AN/TPS-53. Troops continue to call the new version "FireFinder" or "counterfire radar." Does it all make more sense now?
Two years ago the U.S. began sending the AN/TPS-53 to Afghanistan. This came two years after the U.S. Army successfully tested this new artillery and mortar finding radar. Easier to use and repair, as well as more reliable than its predecessor (the AN/TPQ-36/37), the TPS-53 can also scan all around (360 degrees), rather than just 90 degrees (as with the older system), and is faster as well. The army wants to buy at least 180 TPS-53s, for about $9 million each. But so far the army only has money to buy about fifty of them. The older FireFinder is cheaper and still gets the job done. This is why some countries (like Iraqi) want it. Many Iraqis have seen the older FireFinder in action. They know it works.
The older FireFinder (AN TPQ-36/37) radar had to overcome a bad reputation it acquired when it first came to Iraq. That was often for failing to detect incoming mortar fire. These were problems that were fixed. FireFinder was developed in the 1970s, based on Vietnam experience with enemy mortar and rocket attacks, but didn't get a real combat workout until after September 11, 2001.
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 were often failing to catch incoming fire, either because of equipment failure or because the enemy was using tactics that fool the radar. For example, in Iraq, American bases were 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 weapon's position. If the mortar was too far below the radar, FireFinder could not accurately spot where the fire was coming from.
Another problem was that if the mortar was too close FireFinder was much less likely to quickly determine where the fire was coming from. So the enemy mortar teams got as close as they could before firing. This still made 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 TPS-53, 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 TPS-53. 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 TPS-53 replaces a significant number of them.