Well now, it looks like North Korea has found a new way of provoking the U.S. and its South Korean allies -- GPS jamming. A U.S. Army RC-7B Crazy Hawk reconnaissance plane was forced to make an emergency landing last March after the North jammed its GPS receiver.
From South Korea's Chosun Ilbo newspaper:
According to a report the Defense Ministry submitted to Democratic Party lawmaker Ahn Kyu-baek of the National Assembly's Defense Committee, the RC-7B took off from its base at 8:30 p.m. on March 4 but had to make an emergency landing about 45 minutes later due to disruption of its GPS functions by jamming signals transmitted from Haeju and Kaesong in North Korea at intervals of five to 10 minutes that afternoon.Based on the Dash-7 turboprop airliner, the little-known RC-7B (shown above) can almost be thought of as a low-flying JSTARS. It's got a Synthetic Aperture Radar/ground scanning radar that allows operators to look for moving targets like enemy tanks and also features electro-optical/infrared cameras. It can also be fitted with gear to intercept enemy communications.
The jamming signals also disrupted the GPS devices of coastal patrol boats and speed boats of the South Korean Navy. Several civilian aircraft in the Gimpo area were also affected.
The North deploys vehicle-mounted jammers that can disrupt signals within 50-100 km and is reportedly developing a jamming device capable of disrupting signals more than 100 km away.
Update: The Pentagon is denying that a U.S. plane was forced to land because of North Korean GPS jamming. I've got to admit, when I read this, my first thought was 'would a jammed GPS signal really force a U.S. military aircraft to abort a mission?'