A jammer can block radio communications on devices that operates on a given radio frequencies within its range (i.e., within a certain distance of the jammer) by emitting a noise radio carrier. A gps jammer generates a 1575.42 Mhz interference to prevent your GPS unit from receiving correct positioning signals. The GPS jammer is typically a small, self-contained, battery powered and transmit signal over a small radius.
The second was a spinoff of the Russian system manufactured domestically in North Korea, which is believed to have similar capabilities but costs less on the open market. South Korean intelligence has claimed that in early 2010, North Korea purchased a new 24-Watt jammer from Russia – capable of jamming GPS reception within a 400 kilometer radius, which basically covers the entire Korean Peninsula.
Last year the British government announced that it is Doing Something™ about the perceived threat of drones in the hands of amateurs. This amounts to mandatory registration and safety tests – in effect, licensing. It appears that DJI is hoping its multiple-guess quiz will be incorporated as the testing element of the British licensing scheme, which would put it at even more of a commercial advantage against its rivals.
Why is this important? Well, presumably a Southern invasion would require some sort of GPS signal for logistical coordination. However, I seriously doubt the satellite signals available to both military and civilian devices aren’t being bolstered by some secret system that we don’t know about. I mean I love my Forerunner and all, but I wouldn’t go into battle with it.
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.