Russia jamming US smart bombs in Ukraine, leak documents say. Leak documents in a defense department official confirm that American-made smart bombs are missing their targets in Ukraine due to Russian electronic jamming. Some of the weapons are also failing to detonate because of technical issues that Ukrainian troops have since fixed. The Pentagon began sending Kiev advanced equipment in December. That could convert unguided munitions into precision-guided smart bombs. The smart bombs, called Joint Direct Attack Munitions, JDAMs, have experienced higher than expected dud rates and have missed their targets on the battlefield. The bomb fuses were not arming when they were released in some cases, causing the weapon to fail to detonate, but Ukrainian troops fixed the issue. Russia is using GPS jamming to interfere with the weapons targeting process, causing the JDAMs and other American weapons to miss their mark. Russian officials believe that Russian jamming is causing the JDAMs to fail, and they suspect that other American weapons are also affected. Boeing, which makes the guidance kits, declined to comment on the issue, and a defense department spokesperson declined to comment on the leaked documents. The Joint Direct Attack Munition, JDAM, is a guidance kit that converts unguided bombs or dumb bombs into all-weather precision-guided munitions. JDAM-equipped bombs are guided by an integrated inertial guidance system coupled to a global positioning system, GPS, receiver, giving them a published range of up to 15 nautical miles, 28 kilometers. JDAM-equipped bombs range from 500 to 2,000 pounds, 230 to 910 kilograms. The JDAMs guidance system was jointly developed by the United States Air Force and United States Navy, hence the Joint, in JDAM. When installed on a bomb, the JDAM kit is given a GBU-guided bomb unit identifier, superseding the Mark 80 or BLU-bomb-live unit, the main culture of the bomb to which it is attached. The JDAM is not a standalone weapon, rather it is a bolt-on, guidance package that converts unguided gravity bombs into precision-guided munitions. The key components of the system consist of a tail section with aerodynamic control surfaces, A, body, straight kit, and a combined inertial guidance system and GPS guidance control unit. The JDAM was meant to improve upon laser-guided bomb and imaging infrared technology, which can be hindered by bad ground and weather conditions. Laser seekers are now being fitted to some JDAMs. From 1998 to November 2016, Boeing completed more than 300,000 JDAM guidance kits. In 2017, it built more than 130 kits per day. As of February 2020, 430,000 kits had been produced.