For the last five years, South Korean intelligence has been trying to get their hands on North Korea's new GPS jammer. The South Korean recently revealed that they had evidence that these jammers were now mounted on North Korean electronic warfare vehicles. These jammers are used to spoil the aim of GPS guided bombs and missiles, and are believed to have a range of 50-100 kilometers. South Korea believes the jammer technology was obtained from Russia.
The U.S., NATO, Israel and several Middle Eastern nations (friendly to the U.S.) are big users of GPS guided weapons. The North Korean device is being offered to Middle Eastern Nations (as in Syria, Iran and Hizbollah), and is touted as superior to the Russian model (which Iraq had, and used, without much success, in 2003). The Russians have since improved their technology, but the U.S. believes its anti-jammer devices are capable to dealing with the new Russian gear. One is never sure unless you can test the anti-jammer technology against the jammer. Thus the eagerness to get a North Korean jammer into the hands of U.S. Air Force anti-jammer experts for examination. Many GPS experts doubt that the North Korean jammer actually exists, as the North Korean have never exhibited much talent in that area of technology. But the Russians have, and apparently another bit of Russian military technology has leaked into North Korea, despite all the embargos against such transactions.