North may be jamming GPS systems on airliners

A total of 252 civilian airliners flying in and out of South Korea reported malfunctions of their GPS navigation systems due to jamming signals sent from unidentified places, raising suspicions that Pyongyang is attempting an electronic attack.

“From 6:14 a.m. on April 28 to 10:40 a.m. on May 2, 241 domestic and nine foreign airplanes flying in and out Incheon International Airport and Gimpo International Airport were affected by jamming signals,” an official of the Ministry of Land, Transport and Maritime Affairs told reporters yesterday. “We have ordered all civilian aviation companies to be cautious of the electronic interference.

“However, normally, most airplanes use an inertial navigation system, using the GPS device as an alternative,” the official added. “So there hasn’t been an accident yet.”

The ministry official said most of the electronic jamming happened near Incheon or in the Gyeonggi region. Those civilian airplanes aren’t equipped with GPS jammer detectors unlike military aircraft, industry officials say.

Pyongyang announced on April 23 that it will stage a “special action” in an unprecedented, “peculiar” way, in retaliation for Seoul’s recent hostile remarks and acts against the regime.

Seoul officials and media are closely following whether the special action means the electronic attack or not.

“We assume that the jamming signals stemmed from regions near the city of Kaesong,” Kim Chun-o, a Land Ministry official told reporters. “We are investigating the specifics of the electronic signals.”

It’s not the first time that North Korea reportedly jammed GPS satellite signals in the South. In March 2011, when the Korea-U.S. annual joint military exercise was going on in the West Sea, jamming signals scrambled the GPS system of coastal patrol ships and high-speed military boats, forcing a U.S. reconnaissance aircraft to make an emergency landing.

Government sources say that North Korea owns a wide range of some 20 jamming devices imported from Russia, including ones that can be mounted on a carrier with a range of 50-100 kilometers (31-62 miles). The North Korean jammers are reportedly installed near the Demilitarized Zone.

By Kim Hee-jin [heejin@joongang.co.kr]