South Korea has ordered 361 American CBU-105 half ton bombs, for delivery in 2016. South Korea had earlier bought 22 for testing and was satisfied with the results. The CBU-105 uses a form of GPS guidance where GPS location at time of bomb release is stored in the CBU-105 and then the internal INS (Inertial Navigation System) takes over and puts the CBU-105 within 26 meters of the aiming point before the bomblets are released. CBU-105 glides up to 16 kilometers to its target before the release.
Each CBU-105 is actually a container carrying 40 BLU-108/B SFW (sensor fused munitions) bomblets. These were originally called SADARM (Search And Destroy Armor Munitions) when first created in the 1980s. Individual SADARMs have their own radar and heat sensor that searches for armored vehicles below and destroys them with a special shaped charge warhead. The SADARM sensors can search and attack vehicles within an area of roughly 150 x 360 meters. The original SADARM design of the 1980s also had the “bomblets” carried by artillery (or mortar) shells or artillery rockets. The self-forging metal projectile used by SADARM punches through the thinner armor on the top of the vehicle. If a target is not found, SADARM self-destructs.
The first use of the CBU-105 was on April 2nd, 2003, when a B-52 dropped six of them on an Iraqi army column moving south from Baghdad. Most of the vehicles were later found destroyed by SADARM. Peacetime tests of the CBU-105 have shown similar results, as the South Korean tests confirmed.
South Korea is ostensibly buying the CBU-105s to deal with North Korean tanks using one of the few trafficable routes through the DMZ into South Korea during an invasion. North Korea is less and less likely to try this, meaning the CBU-105s could be used against Chinese tanks entering North Korea after a government collapse up there. South Korea hopes it never comes to that, but the CBU-105s gives North Korean and Chinese commanders one more thing to worry about.