North Korea's continuing attempts to jam South Korea' Global Positioning System may be aimed at disrupting the navigation systems of aircraft, government officials said as the communist country continued to send jamming signals on Tuesday.

In a provocative operation that started in late March, North Korea has been sending GPS-jamming signals across the border. The signals began last Thursday and continued on and off into Tuesday, according to military and information and communication technology sector officials. 

"An assessment showed that North Korea's near daily GPS-jamming activity seems to be targeting aircraft's navigation equipment," an intelligence source said, asking not to be named.

But the North Korean operation has not yet resulted in any trouble with South Korea's aircraft because they use both GPS and an inertial navigation system that is immune to jamming attacks, the official said.

In the GPS disruption campaign so far, the North has sent jamming signals on a total of 100 occasions and their maximum output reached more than 45 decibels, the official said.

The strength of the signals are constantly lessening or increasing in what appears to be a new type of assault operation, according to the official.

The country's ICT ministry said the jamming attack has not led to any major GPS disruption locally as of Tuesday, although a total of 962 airplanes have been exposed to the malicious signals.

Nearly 700 fishing ships have been subject to the signals as well, while a total of 1,786 mobile telecommunication base stations have been exposed. 
Officials said North Korea had previously launched similar jamming assaults three times between 2010 and 2012, which partly disrupted the GPS-guided navigation of some 1,000 passenger jets as well as of the military's unmanned aerial vehicles. (Yonhap)