How South Korea is Countering North Korea’s GPS Jamming Tactic

On June 19, Incheon announced that it had begun performance testing a device to prevent interference from North Korea’s Global Positioning System (GPS) signals, which have recently caused fishing losses and shipwreck damage. GPS is a satellite navigation system that uses satellite signals to provide location and time information for ships, cars, and aircraft. While India and Japan utilize their satellite systems, South Korea is still in the development phase and primarily uses GPS, operated by the U.S.

The strength of the GPS signals transmitted from satellites 12,427 miles above is approximately 1/100th of a cell phone signal, which can be easily disrupted by stronger signals from nearby base stations, leading to incorrect location information.

North Korea primarily disrupts signals horizontally from points close to the Five West Sea Islands. GPS signal interference can cause economic losses by incorrectly displaying the location of fishing vessels in operation at sea or by preventing them from finding fishing gear installed on fishing grounds.

Taking advice from academia, Incheon developed a GPS signal jamming prevention device to ensure safe fishing operations for fishermen and to prevent economic losses. The device has been installed on the Incheon Fisheries Guidance Vessel (Incheon 201) for performance testing. The radio interference prevention device was manufactured based on the fact that North Korea’s jamming radio waves are emitted horizontally like a flash and are ineffective when blocked by mountains or buildings, and that aluminum tape can block radio waves.

The device involves covering the GPS-receiving antenna with a protective shield. By keeping the top open, vertical signals from satellites can be received normally, while the sides and bottom are covered with an aluminum tape shield to block horizontally arriving jamming signals.

The materials used to manufacture this device cost around $17, making it easily affordable.

Head of the Incheon Fisheries Division Oh Guk Hyun said, “Currently, the navigation devices of small fishing vessels in South Korea rely solely on GPS and are helpless in the event of signal jamming by North Korea. We developed this device in response. If the performance test is successful, we plan to promote the effectiveness of the prevention device nationwide.”