High power jammers will determine war
It is believed that a one-kilowatt portable GPS signal jammer can block a GPS receiver from as far away as 80 kilometers. Russia has several powerful military units in the vicinity of the border, among them the 200th Independent Motor Rifle Brigde in Pechenga.
An average GPS jammer will create an impenetrable bubble around the vehicle for about 500 meters. In addition to that, these devices are also able to block any locating ability from phones or other mobile tracking devices.
GPS jammers work by broadcasting a strong local signal on the same frequency as GPS, effectively drowning the weak GPS signal broadcast by satellites.
South Korean government officials report that the jamming operation, which began in late March, has been targeting aircraft navigation equipment. North Korea has reportedly broadcast a jamming signal on 100 occasions. A total of 962 planes have been affected by the jamming, as well as nearly 700 fishing vessels. The jamming has also affected cell phone base stations.
North Korea developed its GPS jamming capability in response to GPS-guided weapons that could be used by South Korean and U.S. forces in the event of war. The country maintains a regiment-sized GPS jamming unit near the capital of Pyongyang and battalion-sized units near the demilitarized zone.
South Korean civil aviation is particularly vulnerable to military jammer because Incheon International Airport—which serves the greater Seoul metropolitan area—is close to the border with North Korea. Incheon is only 23 miles from the demilitarized zone. 49.2 million passengers passed through Incheon in 2015, making it one of the busiest airports in the world.
The jamming is taking place even as the head of U.S. Cyber Command, Admiral Michael S. Rogers, warns that the country is bolstering its cyberwarfare capabilities capabilities it may well have shown off during the major cyberattack on Sony Pictures Entertainment, largely suspected to be a state-sponsored attack following the release of the film The Interview.