North's GPS Jamming Continues for Two Days... Source Location [Yang Nak-gyu's Defence Club]

More than 5 Forward Areas Deployed in Gaeseong Region
Low Signal Output Means No Military or Civilian Damage Yet

On the 30th, North Korea attempted to jam GPS signals by transmitting interference from north of the Northern Limit Line (NLL) in the West Sea towards the south. This follows a similar GPS jamming attack from north of the West Sea NLL towards the south in the early hours of the 29th, marking the second consecutive day.

[Image source=Yonhap News]

According to the Joint Chiefs of Staff, GPS jamming signals were detected around 7:50 a.m. this morning in the northwestern island area. However, there have been no reported restrictions on military operations due to the GPS interference so far. The signal output was low, causing no significant damage to military or civilian sectors.

GPS signals are transmitted from about 20,000 km above the earth, and when they reach the ground, even low-power signals can cause interference and induce errors. This is a form of jamming. Jamming refers to the act of deliberately transmitting strong signals on the same frequency towards a specific target to disrupt reception. It can be critical to the military, communications, shipping, and aviation sectors that rely on GPS. In response, the military is operating detection systems to counter North Korea’s GPS jamming and is maintaining a readiness posture by sharing real-time information with related agencies such as the Ministry of Science and ICT, Ministry of Land, Infrastructure and Transport, Ministry of Oceans and Fisheries, and the Korea Coast Guard.

North Korea’s jamming transmission sites were limited to one location in Kaesong in 2010 but expanded to five locations in 2016, including Haeju, Yeonan, Pyeonggang, Kaesong, and Mount Kumgang areas. North Korea also sent GPS jamming signals from these sites in March of this year. In March, immediately after the conclusion of the South Korea-U.S. joint exercise ‘Freedom Shield’ (FS), North Korea attempted jamming for three days. At that time, North Korea repeatedly tried to jam GPS signals from north of the West Sea NLL towards the airspace over the five western islands controlled by South Korea (Baengnyeongdo, Daecheongdo, Socheongdo, Yeonpyeongdo, and Soyeonpyeongdo). North Korea has previously attempted GPS jamming timed with South Korea-U.S. joint exercises. After the 2010 Eulji Freedom Guardian (UFG) exercise, North Korea attempted GPS jamming targeting the Key Resolve (KR) exercise in March 2011 and the South Korea-U.S. joint air combat exercises in April-May 2012.