GPS Jamming

I've been following John Wiseman's Twitter feed for a while, where he has been posting regular maps showing where pilots have experienced weak GPS signals. John has now released an interactive map, GPS Jam, which provides a daily map of where in the world GPS jamming is currently being experienced by aircraft 

To make his maps John processes every day's data from the ADS-B exchange. He can then accurately map where in the world aircraft have been reporting poor navigation accuracy. All aircraft broadcast ADS-B signals, which are used to calculate the plane's real-time location. These signals are also used to measure GPS accuracy. On ADS-B exchange all aircraft tracking reports include an 'accuracy' section, which provides self-reported data about the accuracy of the GPS signals being sent by the aircraft. 

GPS Jam uses these reports to show all the aircraft reporting poor navigation accuracy. The map is therefore able to identify areas around the world where GPS jamming is currently being used. On the map you might see evidence of GPS jamming around Syria, Cyprus and Israel, these are areas where there has been evidence of GPS jamming for a number of years. According to John Wiseman you might also see evidence of GPS jamming in the U.S., where there is often GPS jamming during military testing, especially in the West and Southwest. You may also see GPS jamming around Moscow, where it is often used by oligarchs to protect their expensive dachas from invasive drones.

John first started mapping GPS jamming before the Russian invasion of Ukraine. He hoped that the maps might provide an early indication of the start of the invasion and where Russia was concentrating its forces. Unfortunately, because airlines now avoid flying over Ukraine when possible, there isn't enough data to determine where the Russian military are using GPS jamming in and around Ukraine.

During the last decade there has been increasing evidence that Russia has been using GPS jamming around the world in order to disrupt its perceived enemies. This has been done with little regard to the dangers that blocking GPS signals poses to civilian aircraft and other vehicles which rely on GPS signals to navigate safely. 

Russia uses electronic warfare weapon systems, such as Borisoglebsk 2, to disrupt communications and GPS systems. GPS systems work by receiving radio signals from four or more satellites. It is relatively easy to block or jam those radio signals. GPS jamming works by sending out radio waves on the same frequencies which the satellites use in order to override or distort the radio signal. GPS spoofing works by sending radio signals which mimic the radio signals sent by the satellites. If a GPS unit can't receive the radio signals from four or more satellites or receives a spoofed signal then it can't accurately calculate its position on Earth.