MD-80 Series (DC-9-80) Undifferentiated or Other Model
Air Traffic Control Fully Certified
Other / Unknown
ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
ATC Equipment / Nav Facility / Buildings; Procedure
Air Carrier X checked on FL340 destination SMF. Flight plan read as expected MVA.SWR.Flunk3.SMF. Four minutes later; I observed the aircraft 10 miles South of MVA VOR. I inquired at got an unreadable response for which I replied with maintain present acknowledge with 'IDENT.' Pilot then clearly read back the present heading clearance. I then asked if pilot was aware they were approximately 10 mile off course to the South and if they were having any GPS issues. After a slight delay the pilot replied 'yes we are.' GPS jamming was taking place by [the Military]. If the pilot would have noticed they were off course before I did and corrected the course it would have caused aircraft to turn right approximately 30-40 degrees into opposite direction Eastbound FL325 climbing to FL350. Aircraft were laterally separated by approximately 7 miles. Not sure as to why GPS jamming was taking place but maybe it should only take place during mid shift operations.
ZOA Controller noted an enroute aircraft approximately ten miles off course potentially leading to a loss of separation. After questioning the pilot; Military GPS interference was identified as the causal factor.