Ships in the southern Baltic Sea were reported to have lost their GPS satellite navigation capabilities for several hours on January 16th / 17th after Russia ramped up its Tobol interceptions system in the Kaliningrad exclave.
On January 16th and 17th previously unheard-of levels of GPS interference were observed in northern and central Poland. This interference extended out into the Baltic, although it does not appear as if whips were the primary target.
Polish news outlet Radio Zet suggested that the outages could have been caused either by NATO exercises in the area or tests of Russian electronic warfare (EW) systems emanating from the Kaliningrad region.
A January 18th report from the Institute for the Study of War (ISW) said that the Swedish Military Intelligence and Security Service (MUST) had begun investigations into the disturbances. Lt Col. Joakim Paasikivi from the Swedish military said that there was evidence that Russia had previously interfered with GPS signals in northern Europe.
Russian media reported that EW units of the Russian Baltic Fleet had been training on the multi-functional Borisoglebsk-2 EW system in the Russian Kaliningrad exclave since mid-December. The suggestion therefore was that Russia could have installed EW capabilities in the Kaliningrad exclave.