a preprogrammed image surrounding the target - it is similar technology to the DSMAC in the BGM-109 Tomahawk. EU sources claim this guidance package can hit completely hidden targets providing their location is well known relative to visually prominent features surrounding the aimpoint. It is likely the bomb needs to be programmed on the ground, although this is apt to change now with the added computing power in recent Su-30 variants. Multiple rounds can be released in a single pass at multiple aimpoints, not unlike the JDAM. While EU sources speculate on the existence of a thermal imaging variant, its existence cannot be confirmed as no photographs are available showing the Zinc Sulphide or Fluoride glass nose windows required. As Russia's industry is now experimenting with QWIP Focal Plane Array imaging chips, a day/night thermal imaging variant is a likely future prospect. The design changes would be in a revised gimbal with a cooling assembly and an IR transmissive window. The most recent variants are the KAB-500S-E  and KAB-1500S-E, equipped with a satellite/inertial guidance system analogous to the US JDAM weapons. Their production status is currently unclear, but trial drops are known to have been performed. The 3,000 lb (1,500 kg) class KAB-1500 bombs are the heavyweights, with blast, blast fragmentation and subcalibre bunker busting warhead options, the latter claimed to be capable of penetrating up to 20 metres of soil and 2 metres of reinforced concrete. The 1,000 lb (500 kg) class KAB-500 bombs are GBU-16/32/35 equivalents, with blast,