According to the Choson Ilbo:
A mysterious intermittent failure of Global Positioning System receivers on naval and civilian craft in some parts of the west coastal region from Aug. 23-25 was “partly” caused by North Korea, Defense Minister Kim Tae-young claimed Monday.
During a parliamentary audit of the Defense Ministry, Grand National Party lawmaker Chung Mi-kyung asked the minster whether he thinks the GPS failure along the west coast in August was caused by North Korea.
“We believe that North Korea is capable of disrupting GPS reception within the distance of 50 to 100 km,” Kim said. “However, the detention of South Korean fishing boat Daeseung on Sept. 8 on the East Sea is irrelevant to this issue as it was too far away from North Korea.”
Since the late 1990s, North Korea imported from Russia equipment that disrupts GPS reception, modified it, and made its own version. It has also been trying to export the equipment to the Middle East, he said.
North Korea’s GPS interrupter is believed to be effective in preventing the South Korean and U.S. military’s GPS-guided bombs and missiles such as Joint Direct Attack Munition (JDAM) from hitting their target accurately.
Read the full story here:
N.Korea ‘Partly’ Behind GPS Interruptions in East Sea
Choson Ilbo
10/5/2010
As someone who is involved with many radiolink designs, the ‘partialy’ comment is intriguing. There are two ways for gps to fail over multiple users: satellite shutdown and jamming signal. Because the failure was in a limited area and followed topographical boundaries, it is probably not due to satellite manipulation (US responsibility). The failure occured only along the coast, which points to a jamming signal from a ship. If the truth is being told about ‘partial’ responsibility, someone else other than dprk must be jamming as well. In this location we can surmise that dprk, rok, prc, and usa have relevant ships operating. I doubt prc would participate in jamming, they would understand how to do it well and running a test like this would gain nothing for the political risk. I feel perhaps rok responded with similar electronic warfare techniques. This sort of sabre rattling indicates tensions in this sea have not decreased much compared to economic indicators such as kaesong. Again, this all relies on the accuracy of the quote in the article.