During June 2017, a tanker ship traveling in the Black Sea experienced a GPS disruption resulting in a 25 mile location discrepancy.  Approximately 20 other ships in the same area experienced GPS disruption as well.    Evidence from this incident points towards a coordinated effort to disrupt GPS; indicating the presence of entities with the ability to disrupt satellite navigation systems over a fairly large area and using sophisticated methods which not only deny GPS service but also provide hazardously misleading information.  Article Link