By Sam Doak, OSINT producer
On 14 March, a plane carrying Defence Secretary Grant Shapps experienced issues relating to its navigation systems when flying near the Russian enclave of Kaliningrad.
While the flight landed safely in the UK, it is one of many that has been affected by GPS jamming in the region in recent months.
According to available data, the areas being routinely affected span from the coast of western Poland to Finland.
Whatever is interfering with GPS systems appears to operate intermittently, as data from some days shows fewer reports of navigational issues than others.
Increasing attention has been paid to this phenomenon in recent days after reports that more than 1,600 flights were affected between 24-26 March.
According to reports, some of the recent interference has been the result of "spoofing", which is when a transmitter is used to interfere with a GPS system by sending signals that either carry false location data or none.
While the origin of this interference has not been publicly proven, areas around Kaliningrad are routinely unaffected, according to available ADS-B data.
With few alternative explanations, many have claimed that Russian forces in the region are responsible for the jamming.
Among those who have pointed the finger at the Russian government are the commander of the Estonian Defence Forces, and a director at the French civil aviation authority.