A GPS jammer in Russia near St Petersburg is disrupting aircraft GPS signals over Estonia, affecting flights and causing aviation navigation issues.

A GPS jammer located in Russia, southwest of St Petersburg roughly halfway between Narva, Estonia and St Petersburg, is causing GPS jamming affecting aircraft in and around Estonia and disrupting flights such as the Helsinki-Tartu route. The jammer's location was determined by plotting the highest density of intersecting radio horizons of jammed aircraft and confirmed using drone-based GPS signal loss observations at 60 meters altitude near Narva. The jammer is almost always operational, affecting a higher proportion of aircraft around Estonia compared to surrounding regions. This hostile signal impacts civilian and potentially military aviation navigation safety in Estonian airspace.