The Swedish mobile artillery-hunting radar system, called ARTHUR, was developed in the 1990s, but was found wanting during its first combat use recently in Afghanistan. Canadian forces there reported that, of 3,200 "incoming objects" ARTHUR reported, only two turned out to be real. There were other problems as well, but the large number of false positives was particularly worrisome. These were often caused by friendly aircraft, or distant electric transmission line towers, being mistook for incoming fire.
ARTHUR is carried in a Bv206 tracked vehicle and costs $20 million per system. The radar can detect shells or rockets fired from up to 40 kilometers away. Within the few seconds, the systems computer can calculate the location of the firing artillery to within two meters. Given the availability of GPS guided shells (Excalibur) and rockets (GMLRS), you can have return (counterbattery) fire on the enemy artillery within a minute.
South Korea, another buyer of ARTHUR, is particularly concerned about the massive numbers of North Korean artillery weapons aimed at their capital, Seoul. ARTHUR, if linked electronically with artillery units equipped with Excalibur or GMLRS, could shut down a lot North Korean artillery very quickly. But only if ARTHUR can deliver on its promise to track up to eight shells a simultaneously, and handle about a hundred a minute. Now there is doubt.
In South Korea, ARTHUR will be replacing the American AN TPQ-36/37 FireFinder artillery and mortar finding radar, which has gotten a bad reputation of late. 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, but now several hundred million dollars worth have been 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 area. 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 they open up. 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 thirty years ago, and begin developing a new system, one 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 a replacement system. The upgrades have also been made available to other users of FireFinder (including, just in the Middle East, Egypt, Israel, Jordan, Saudi Arabia and Turkey.)
Meanwhile, ARTHUR has been selling to many NATO countries, as it is of more recent vintage than FireFinder, and has gotten rave reviews from existing users. But these reviews were based on peacetime tests, not actual battlefield use. The Canadian experience has had a chilling effect on ARTHUR sales.
The combat experiences of FireFinder and ARTHUR should inspire developers of this kind of equipment to come up with more realistic testing procedures.